Java中的使用及连接Redis数据库(附源码)

引言：

本文主要分享了redis如何在idea中部署，运行；模拟加入redis的操作；

目录结构

1. 在idea中搭建redis

1.1 创建项目

新建含有web的springboot项目；

搭建项目参考：springboot超详细笔记：https://blog.csdn.net/weixin_42601136/article/details/108396511

1.2 添加依赖（不够手动添加）

<dependencies>
  <!--  1、 jedis-->
  <dependency>
    <groupid>redis.clients</groupid>
    <artifactid>jedis</artifactid>
    <version>2.9.0</version>
  </dependency>
  <!--  2、 junit测试-->
  <dependency>
    <groupid>junit</groupid>
    <artifactid>junit</artifactid>
    <version>4.12</version>
  </dependency>

  <dependency>
    <groupid>org.springframework.boot</groupid>
    <artifactid>spring-boot-starter-jdbc</artifactid>
  </dependency>
  <dependency>
    <groupid>org.springframework.boot</groupid>
    <artifactid>spring-boot-starter-thymeleaf</artifactid>
  </dependency>
  <dependency>
    <groupid>org.springframework.boot</groupid>
    <artifactid>spring-boot-starter-web</artifactid>
  </dependency>
  <dependency>
    <groupid>org.mybatis.spring.boot</groupid>
    <artifactid>mybatis-spring-boot-starter</artifactid>
    <version>2.1.2</version>
  </dependency>

  <dependency>
    <groupid>mysql</groupid>
    <artifactid>mysql-connector-java</artifactid>
    <scope>runtime</scope>
  </dependency>
  <dependency>
    <groupid>org.projectlombok</groupid>
    <artifactid>lombok</artifactid>
    <optional>true</optional>
  </dependency>
  <dependency>
    <groupid>org.springframework.boot</groupid>
    <artifactid>spring-boot-starter-test</artifactid>
    <scope>test</scope>
  </dependency>
</dependencies>

1.3 测试环境是否搭建成功

@test
  public void test0() {
    //连接redis
    jedis jedis = new jedis("127.0.0.1", 6379);
    //获取kak
    string kaka = jedis.get("kak");
    log.info(kaka);
    //创建datex
    string datex = jedis.set("datex", new date().tostring());
    //获取datex
    string datex1 = jedis.get("datex");
    log.info(datex1);
    //关闭资源
    jedis.close();
  }

1.4 利用json存储数据

@test
  public void test1() {
    jedispool pool = new jedispool("127.0.0.1", 6379);
    jedis jedis = pool.getresource();
    student student = new student(1001, "kak", "man", "20");
    string key = "student";
    string field = "1001";
    string s = jsonutils.objecttojson(student);
    string value = s;
    jedis.hset(key, field, value);
    string hget = jedis.hget(key, field);
    log.info(hget);
    jedis.close();
  }

1.5 以byte的形式存储对象

@test
  public void test02() {
    //连接redis
    jedis jedis = new jedis("127.0.0.1", 6379);
    string key = "student";
    student value = new student(1002, "taotao", "woman", "20");
    //将key和value转换为byte[]
    byte[] bytekey = serializationutils.serialize(key);
    byte[] bytevalue = serializationutils.serialize(value);
    //将key和value存储到redis中
    jedis.set(bytekey, bytevalue);
    //获取value值
    byte[] bytes = jedis.get(bytekey);
    //bytes反序列化为student对象
    student stu = (student) serializationutils.deserialize(bytes);
    system.out.println(stu);
    jedis.close();

  }

1.6 加入连接池的操作

使用连接池操作，可以避免频繁的创建和销毁连接对象的消耗资源

@test
  public void test3(){
    //创建连接池
    genericobjectpoolconfig poolconfig = new genericobjectpoolconfig();
    poolconfig.setmaxtotal(100);//连接池中的最大活跃数
    poolconfig.setmaxidle(10);//最大空闲数
    poolconfig.setminidle(5);//最小空闲数
    poolconfig.setmaxwaitmillis(3000);//连接池空了，3000毫秒后没有获取jedis对象，超时
    //创建连接池
    jedispool pool = new jedispool(poolconfig,"127.0.0.1",6379);
    //通过连接池获取jedis对象
    jedis resource = pool.getresource();
    //获取上面添加的datex
    string value = resource.get("datex");
    log.info(value);

    resource.close();
  }

1.7 管道操作

redis的管道操作，执行一个命令需要先发送请求到redis，需要经历网络延迟，redis还需给客户端一个响应；如果需要一次操作多个命令，可以通过管道，将命令放到客户端的一个pipeline中，之后一次将命令发送到服务端，服务端一次性返回到客户端；

@test
  public void test3(){
    //创建连接池
    genericobjectpoolconfig poolconfig = new genericobjectpoolconfig();
    poolconfig.setmaxtotal(100);//连接池中的最大活跃数
    poolconfig.setmaxidle(10);//最大空闲数
    poolconfig.setminidle(5);//最小空闲数
    poolconfig.setmaxwaitmillis(3000);//连接池空了，3000毫秒后没有获取jedis对象，超时
    //创建连接池
    jedispool pool = new jedispool(poolconfig,"127.0.0.1",6379);
    //通过连接池获取jedis对象
    jedis resource = pool.getresource();
    //获取上面添加的datex
    string value = resource.get("datex");
    log.info(value);

    resource.close();
  }

2. 从数据中查询数据

场景：

将数据存入redis中，避免访问量过大，造成数据库奔溃；

2.1 生成实体类

@test
  public void test3(){
    //创建连接池
    genericobjectpoolconfig poolconfig = new genericobjectpoolconfig();
    poolconfig.setmaxtotal(100);//连接池中的最大活跃数
    poolconfig.setmaxidle(10);//最大空闲数
    poolconfig.setminidle(5);//最小空闲数
    poolconfig.setmaxwaitmillis(3000);//连接池空了，3000毫秒后没有获取jedis对象，超时
    //创建连接池
    jedispool pool = new jedispool(poolconfig,"127.0.0.1",6379);
    //通过连接池获取jedis对象
    jedis resource = pool.getresource();
    //获取上面添加的datex
    string value = resource.get("datex");
    log.info(value);

    resource.close();
  }

2.2 生成实体模板类

package com.sx.kak.po;

import java.util.arraylist;
import java.util.list;

public class studentexample {
  protected string orderbyclause;

  protected boolean distinct;

  protected list<criteria> oredcriteria;

  public studentexample() {
    oredcriteria = new arraylist<criteria>();
  }

  public void setorderbyclause(string orderbyclause) {
    this.orderbyclause = orderbyclause;
  }

  public string getorderbyclause() {
    return orderbyclause;
  }

  public void setdistinct(boolean distinct) {
    this.distinct = distinct;
  }

  public boolean isdistinct() {
    return distinct;
  }

  public list<criteria> getoredcriteria() {
    return oredcriteria;
  }

  public void or(criteria criteria) {
    oredcriteria.add(criteria);
  }

  public criteria or() {
    criteria criteria = createcriteriainternal();
    oredcriteria.add(criteria);
    return criteria;
  }

  public criteria createcriteria() {
    criteria criteria = createcriteriainternal();
    if (oredcriteria.size() == 0) {
      oredcriteria.add(criteria);
    }
    return criteria;
  }

  protected criteria createcriteriainternal() {
    criteria criteria = new criteria();
    return criteria;
  }

  public void clear() {
    oredcriteria.clear();
    orderbyclause = null;
    distinct = false;
  }

  protected abstract static class generatedcriteria {
    protected list<criterion> criteria;

    protected generatedcriteria() {
      super();
      criteria = new arraylist<criterion>();
    }

    public boolean isvalid() {
      return criteria.size() > 0;
    }

    public list<criterion> getallcriteria() {
      return criteria;
    }

    public list<criterion> getcriteria() {
      return criteria;
    }

    protected void addcriterion(string condition) {
      if (condition == null) {
        throw new runtimeexception("value for condition cannot be null");
      }
      criteria.add(new criterion(condition));
    }

    protected void addcriterion(string condition, object value, string property) {
      if (value == null) {
        throw new runtimeexception("value for " + property + " cannot be null");
      }
      criteria.add(new criterion(condition, value));
    }

    protected void addcriterion(string condition, object value1, object value2, string property) {
      if (value1 == null || value2 == null) {
        throw new runtimeexception("between values for " + property + " cannot be null");
      }
      criteria.add(new criterion(condition, value1, value2));
    }

    public criteria andidisnull() {
      addcriterion("id is null");
      return (criteria) this;
    }

    public criteria andidisnotnull() {
      addcriterion("id is not null");
      return (criteria) this;
    }

    public criteria andidequalto(integer value) {
      addcriterion("id =", value, "id");
      return (criteria) this;
    }

    public criteria andidnotequalto(integer value) {
      addcriterion("id <>", value, "id");
      return (criteria) this;
    }

    public criteria andidgreaterthan(integer value) {
      addcriterion("id >", value, "id");
      return (criteria) this;
    }

    public criteria andidgreaterthanorequalto(integer value) {
      addcriterion("id >=", value, "id");
      return (criteria) this;
    }

    public criteria andidlessthan(integer value) {
      addcriterion("id <", value, "id");
      return (criteria) this;
    }

    public criteria andidlessthanorequalto(integer value) {
      addcriterion("id <=", value, "id");
      return (criteria) this;
    }

    public criteria andidin(list<integer> values) {
      addcriterion("id in", values, "id");
      return (criteria) this;
    }

    public criteria andidnotin(list<integer> values) {
      addcriterion("id not in", values, "id");
      return (criteria) this;
    }

    public criteria andidbetween(integer value1, integer value2) {
      addcriterion("id between", value1, value2, "id");
      return (criteria) this;
    }

    public criteria andidnotbetween(integer value1, integer value2) {
      addcriterion("id not between", value1, value2, "id");
      return (criteria) this;
    }

    public criteria andnameisnull() {
      addcriterion("name is null");
      return (criteria) this;
    }

    public criteria andnameisnotnull() {
      addcriterion("name is not null");
      return (criteria) this;
    }

    public criteria andnameequalto(string value) {
      addcriterion("name =", value, "name");
      return (criteria) this;
    }

    public criteria andnamenotequalto(string value) {
      addcriterion("name <>", value, "name");
      return (criteria) this;
    }

    public criteria andnamegreaterthan(string value) {
      addcriterion("name >", value, "name");
      return (criteria) this;
    }

    public criteria andnamegreaterthanorequalto(string value) {
      addcriterion("name >=", value, "name");
      return (criteria) this;
    }

    public criteria andnamelessthan(string value) {
      addcriterion("name <", value, "name");
      return (criteria) this;
    }

    public criteria andnamelessthanorequalto(string value) {
      addcriterion("name <=", value, "name");
      return (criteria) this;
    }

    public criteria andnamelike(string value) {
      addcriterion("name like", value, "name");
      return (criteria) this;
    }

    public criteria andnamenotlike(string value) {
      addcriterion("name not like", value, "name");
      return (criteria) this;
    }

    public criteria andnamein(list<string> values) {
      addcriterion("name in", values, "name");
      return (criteria) this;
    }

    public criteria andnamenotin(list<string> values) {
      addcriterion("name not in", values, "name");
      return (criteria) this;
    }

    public criteria andnamebetween(string value1, string value2) {
      addcriterion("name between", value1, value2, "name");
      return (criteria) this;
    }

    public criteria andnamenotbetween(string value1, string value2) {
      addcriterion("name not between", value1, value2, "name");
      return (criteria) this;
    }

    public criteria andsexisnull() {
      addcriterion("sex is null");
      return (criteria) this;
    }

    public criteria andsexisnotnull() {
      addcriterion("sex is not null");
      return (criteria) this;
    }

    public criteria andsexequalto(string value) {
      addcriterion("sex =", value, "sex");
      return (criteria) this;
    }

    public criteria andsexnotequalto(string value) {
      addcriterion("sex <>", value, "sex");
      return (criteria) this;
    }

    public criteria andsexgreaterthan(string value) {
      addcriterion("sex >", value, "sex");
      return (criteria) this;
    }

    public criteria andsexgreaterthanorequalto(string value) {
      addcriterion("sex >=", value, "sex");
      return (criteria) this;
    }

    public criteria andsexlessthan(string value) {
      addcriterion("sex <", value, "sex");
      return (criteria) this;
    }

    public criteria andsexlessthanorequalto(string value) {
      addcriterion("sex <=", value, "sex");
      return (criteria) this;
    }

    public criteria andsexlike(string value) {
      addcriterion("sex like", value, "sex");
      return (criteria) this;
    }

    public criteria andsexnotlike(string value) {
      addcriterion("sex not like", value, "sex");
      return (criteria) this;
    }

    public criteria andsexin(list<string> values) {
      addcriterion("sex in", values, "sex");
      return (criteria) this;
    }

    public criteria andsexnotin(list<string> values) {
      addcriterion("sex not in", values, "sex");
      return (criteria) this;
    }

    public criteria andsexbetween(string value1, string value2) {
      addcriterion("sex between", value1, value2, "sex");
      return (criteria) this;
    }

    public criteria andsexnotbetween(string value1, string value2) {
      addcriterion("sex not between", value1, value2, "sex");
      return (criteria) this;
    }

    public criteria andageisnull() {
      addcriterion("age is null");
      return (criteria) this;
    }

    public criteria andageisnotnull() {
      addcriterion("age is not null");
      return (criteria) this;
    }

    public criteria andageequalto(string value) {
      addcriterion("age =", value, "age");
      return (criteria) this;
    }

    public criteria andagenotequalto(string value) {
      addcriterion("age <>", value, "age");
      return (criteria) this;
    }

    public criteria andagegreaterthan(string value) {
      addcriterion("age >", value, "age");
      return (criteria) this;
    }

    public criteria andagegreaterthanorequalto(string value) {
      addcriterion("age >=", value, "age");
      return (criteria) this;
    }

    public criteria andagelessthan(string value) {
      addcriterion("age <", value, "age");
      return (criteria) this;
    }

    public criteria andagelessthanorequalto(string value) {
      addcriterion("age <=", value, "age");
      return (criteria) this;
    }

    public criteria andagelike(string value) {
      addcriterion("age like", value, "age");
      return (criteria) this;
    }

    public criteria andagenotlike(string value) {
      addcriterion("age not like", value, "age");
      return (criteria) this;
    }

    public criteria andagein(list<string> values) {
      addcriterion("age in", values, "age");
      return (criteria) this;
    }

    public criteria andagenotin(list<string> values) {
      addcriterion("age not in", values, "age");
      return (criteria) this;
    }

    public criteria andagebetween(string value1, string value2) {
      addcriterion("age between", value1, value2, "age");
      return (criteria) this;
    }

    public criteria andagenotbetween(string value1, string value2) {
      addcriterion("age not between", value1, value2, "age");
      return (criteria) this;
    }
  }

  public static class criteria extends generatedcriteria {

    protected criteria() {
      super();
    }
  }

  public static class criterion {
    private string condition;

    private object value;

    private object secondvalue;

    private boolean novalue;

    private boolean singlevalue;

    private boolean betweenvalue;

    private boolean listvalue;

    private string typehandler;

    public string getcondition() {
      return condition;
    }

    public object getvalue() {
      return value;
    }

    public object getsecondvalue() {
      return secondvalue;
    }

    public boolean isnovalue() {
      return novalue;
    }

    public boolean issinglevalue() {
      return singlevalue;
    }

    public boolean isbetweenvalue() {
      return betweenvalue;
    }

    public boolean islistvalue() {
      return listvalue;
    }

    public string gettypehandler() {
      return typehandler;
    }

    protected criterion(string condition) {
      super();
      this.condition = condition;
      this.typehandler = null;
      this.novalue = true;
    }

    protected criterion(string condition, object value, string typehandler) {
      super();
      this.condition = condition;
      this.value = value;
      this.typehandler = typehandler;
      if (value instanceof list<?>) {
        this.listvalue = true;
      } else {
        this.singlevalue = true;
      }
    }

    protected criterion(string condition, object value) {
      this(condition, value, null);
    }

    protected criterion(string condition, object value, object secondvalue, string typehandler) {
      super();
      this.condition = condition;
      this.value = value;
      this.secondvalue = secondvalue;
      this.typehandler = typehandler;
      this.betweenvalue = true;
    }

    protected criterion(string condition, object value, object secondvalue) {
      this(condition, value, secondvalue, null);
    }
  }
}

2.3 生成studentmapper.java

package com.sx.kak.po;

import java.util.arraylist;
import java.util.list;

public class studentexample {
  protected string orderbyclause;

  protected boolean distinct;

  protected list<criteria> oredcriteria;

  public studentexample() {
    oredcriteria = new arraylist<criteria>();
  }

  public void setorderbyclause(string orderbyclause) {
    this.orderbyclause = orderbyclause;
  }

  public string getorderbyclause() {
    return orderbyclause;
  }

  public void setdistinct(boolean distinct) {
    this.distinct = distinct;
  }

  public boolean isdistinct() {
    return distinct;
  }

  public list<criteria> getoredcriteria() {
    return oredcriteria;
  }

  public void or(criteria criteria) {
    oredcriteria.add(criteria);
  }

  public criteria or() {
    criteria criteria = createcriteriainternal();
    oredcriteria.add(criteria);
    return criteria;
  }

  public criteria createcriteria() {
    criteria criteria = createcriteriainternal();
    if (oredcriteria.size() == 0) {
      oredcriteria.add(criteria);
    }
    return criteria;
  }

  protected criteria createcriteriainternal() {
    criteria criteria = new criteria();
    return criteria;
  }

  public void clear() {
    oredcriteria.clear();
    orderbyclause = null;
    distinct = false;
  }

  protected abstract static class generatedcriteria {
    protected list<criterion> criteria;

    protected generatedcriteria() {
      super();
      criteria = new arraylist<criterion>();
    }

    public boolean isvalid() {
      return criteria.size() > 0;
    }

    public list<criterion> getallcriteria() {
      return criteria;
    }

    public list<criterion> getcriteria() {
      return criteria;
    }

    protected void addcriterion(string condition) {
      if (condition == null) {
        throw new runtimeexception("value for condition cannot be null");
      }
      criteria.add(new criterion(condition));
    }

    protected void addcriterion(string condition, object value, string property) {
      if (value == null) {
        throw new runtimeexception("value for " + property + " cannot be null");
      }
      criteria.add(new criterion(condition, value));
    }

    protected void addcriterion(string condition, object value1, object value2, string property) {
      if (value1 == null || value2 == null) {
        throw new runtimeexception("between values for " + property + " cannot be null");
      }
      criteria.add(new criterion(condition, value1, value2));
    }

    public criteria andidisnull() {
      addcriterion("id is null");
      return (criteria) this;
    }

    public criteria andidisnotnull() {
      addcriterion("id is not null");
      return (criteria) this;
    }

    public criteria andidequalto(integer value) {
      addcriterion("id =", value, "id");
      return (criteria) this;
    }

    public criteria andidnotequalto(integer value) {
      addcriterion("id <>", value, "id");
      return (criteria) this;
    }

    public criteria andidgreaterthan(integer value) {
      addcriterion("id >", value, "id");
      return (criteria) this;
    }

    public criteria andidgreaterthanorequalto(integer value) {
      addcriterion("id >=", value, "id");
      return (criteria) this;
    }

    public criteria andidlessthan(integer value) {
      addcriterion("id <", value, "id");
      return (criteria) this;
    }

    public criteria andidlessthanorequalto(integer value) {
      addcriterion("id <=", value, "id");
      return (criteria) this;
    }

    public criteria andidin(list<integer> values) {
      addcriterion("id in", values, "id");
      return (criteria) this;
    }

    public criteria andidnotin(list<integer> values) {
      addcriterion("id not in", values, "id");
      return (criteria) this;
    }

    public criteria andidbetween(integer value1, integer value2) {
      addcriterion("id between", value1, value2, "id");
      return (criteria) this;
    }

    public criteria andidnotbetween(integer value1, integer value2) {
      addcriterion("id not between", value1, value2, "id");
      return (criteria) this;
    }

    public criteria andnameisnull() {
      addcriterion("name is null");
      return (criteria) this;
    }

    public criteria andnameisnotnull() {
      addcriterion("name is not null");
      return (criteria) this;
    }

    public criteria andnameequalto(string value) {
      addcriterion("name =", value, "name");
      return (criteria) this;
    }

    public criteria andnamenotequalto(string value) {
      addcriterion("name <>", value, "name");
      return (criteria) this;
    }

    public criteria andnamegreaterthan(string value) {
      addcriterion("name >", value, "name");
      return (criteria) this;
    }

    public criteria andnamegreaterthanorequalto(string value) {
      addcriterion("name >=", value, "name");
      return (criteria) this;
    }

    public criteria andnamelessthan(string value) {
      addcriterion("name <", value, "name");
      return (criteria) this;
    }

    public criteria andnamelessthanorequalto(string value) {
      addcriterion("name <=", value, "name");
      return (criteria) this;
    }

    public criteria andnamelike(string value) {
      addcriterion("name like", value, "name");
      return (criteria) this;
    }

    public criteria andnamenotlike(string value) {
      addcriterion("name not like", value, "name");
      return (criteria) this;
    }

    public criteria andnamein(list<string> values) {
      addcriterion("name in", values, "name");
      return (criteria) this;
    }

    public criteria andnamenotin(list<string> values) {
      addcriterion("name not in", values, "name");
      return (criteria) this;
    }

    public criteria andnamebetween(string value1, string value2) {
      addcriterion("name between", value1, value2, "name");
      return (criteria) this;
    }

    public criteria andnamenotbetween(string value1, string value2) {
      addcriterion("name not between", value1, value2, "name");
      return (criteria) this;
    }

    public criteria andsexisnull() {
      addcriterion("sex is null");
      return (criteria) this;
    }

    public criteria andsexisnotnull() {
      addcriterion("sex is not null");
      return (criteria) this;
    }

    public criteria andsexequalto(string value) {
      addcriterion("sex =", value, "sex");
      return (criteria) this;
    }

    public criteria andsexnotequalto(string value) {
      addcriterion("sex <>", value, "sex");
      return (criteria) this;
    }

    public criteria andsexgreaterthan(string value) {
      addcriterion("sex >", value, "sex");
      return (criteria) this;
    }

    public criteria andsexgreaterthanorequalto(string value) {
      addcriterion("sex >=", value, "sex");
      return (criteria) this;
    }

    public criteria andsexlessthan(string value) {
      addcriterion("sex <", value, "sex");
      return (criteria) this;
    }

    public criteria andsexlessthanorequalto(string value) {
      addcriterion("sex <=", value, "sex");
      return (criteria) this;
    }

    public criteria andsexlike(string value) {
      addcriterion("sex like", value, "sex");
      return (criteria) this;
    }

    public criteria andsexnotlike(string value) {
      addcriterion("sex not like", value, "sex");
      return (criteria) this;
    }

    public criteria andsexin(list<string> values) {
      addcriterion("sex in", values, "sex");
      return (criteria) this;
    }

    public criteria andsexnotin(list<string> values) {
      addcriterion("sex not in", values, "sex");
      return (criteria) this;
    }

    public criteria andsexbetween(string value1, string value2) {
      addcriterion("sex between", value1, value2, "sex");
      return (criteria) this;
    }

    public criteria andsexnotbetween(string value1, string value2) {
      addcriterion("sex not between", value1, value2, "sex");
      return (criteria) this;
    }

    public criteria andageisnull() {
      addcriterion("age is null");
      return (criteria) this;
    }

    public criteria andageisnotnull() {
      addcriterion("age is not null");
      return (criteria) this;
    }

    public criteria andageequalto(string value) {
      addcriterion("age =", value, "age");
      return (criteria) this;
    }

    public criteria andagenotequalto(string value) {
      addcriterion("age <>", value, "age");
      return (criteria) this;
    }

    public criteria andagegreaterthan(string value) {
      addcriterion("age >", value, "age");
      return (criteria) this;
    }

    public criteria andagegreaterthanorequalto(string value) {
      addcriterion("age >=", value, "age");
      return (criteria) this;
    }

    public criteria andagelessthan(string value) {
      addcriterion("age <", value, "age");
      return (criteria) this;
    }

    public criteria andagelessthanorequalto(string value) {
      addcriterion("age <=", value, "age");
      return (criteria) this;
    }

    public criteria andagelike(string value) {
      addcriterion("age like", value, "age");
      return (criteria) this;
    }

    public criteria andagenotlike(string value) {
      addcriterion("age not like", value, "age");
      return (criteria) this;
    }

    public criteria andagein(list<string> values) {
      addcriterion("age in", values, "age");
      return (criteria) this;
    }

    public criteria andagenotin(list<string> values) {
      addcriterion("age not in", values, "age");
      return (criteria) this;
    }

    public criteria andagebetween(string value1, string value2) {
      addcriterion("age between", value1, value2, "age");
      return (criteria) this;
    }

    public criteria andagenotbetween(string value1, string value2) {
      addcriterion("age not between", value1, value2, "age");
      return (criteria) this;
    }
  }

  public static class criteria extends generatedcriteria {

    protected criteria() {
      super();
    }
  }

  public static class criterion {
    private string condition;

    private object value;

    private object secondvalue;

    private boolean novalue;

    private boolean singlevalue;

    private boolean betweenvalue;

    private boolean listvalue;

    private string typehandler;

    public string getcondition() {
      return condition;
    }

    public object getvalue() {
      return value;
    }

    public object getsecondvalue() {
      return secondvalue;
    }

    public boolean isnovalue() {
      return novalue;
    }

    public boolean issinglevalue() {
      return singlevalue;
    }

    public boolean isbetweenvalue() {
      return betweenvalue;
    }

    public boolean islistvalue() {
      return listvalue;
    }

    public string gettypehandler() {
      return typehandler;
    }

    protected criterion(string condition) {
      super();
      this.condition = condition;
      this.typehandler = null;
      this.novalue = true;
    }

    protected criterion(string condition, object value, string typehandler) {
      super();
      this.condition = condition;
      this.value = value;
      this.typehandler = typehandler;
      if (value instanceof list<?>) {
        this.listvalue = true;
      } else {
        this.singlevalue = true;
      }
    }

    protected criterion(string condition, object value) {
      this(condition, value, null);
    }

    protected criterion(string condition, object value, object secondvalue, string typehandler) {
      super();
      this.condition = condition;
      this.value = value;
      this.secondvalue = secondvalue;
      this.typehandler = typehandler;
      this.betweenvalue = true;
    }

    protected criterion(string condition, object value, object secondvalue) {
      this(condition, value, secondvalue, null);
    }
  }
}

2.4 生成studentmapper.xml

<?xml version="1.0" encoding="utf-8" ?>
<!doctype mapper public "-//mybatis.org//dtd mapper 3.0//en" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.sx.kak.mapper.studentmapper" >
 <resultmap id="baseresultmap" type="com.sx.kak.po.student" >
  <id column="id" property="id" jdbctype="integer" />
  <result column="name" property="name" jdbctype="varchar" />
  <result column="sex" property="sex" jdbctype="varchar" />
  <result column="age" property="age" jdbctype="varchar" />
 </resultmap>
 <sql id="example_where_clause" >
  <where >
   <foreach collection="oredcriteria" item="criteria" separator="or" >
    <if test="criteria.valid" >
     <trim prefix="(" suffix=")" prefixoverrides="and" >
      <foreach collection="criteria.criteria" item="criterion" >
       <choose >
        <when test="criterion.novalue" >
         and ${criterion.condition}
        </when>
        <when test="criterion.singlevalue" >
         and ${criterion.condition} #{criterion.value}
        </when>
        <when test="criterion.betweenvalue" >
         and ${criterion.condition} #{criterion.value} and #{criterion.secondvalue}
        </when>
        <when test="criterion.listvalue" >
         and ${criterion.condition}
         <foreach collection="criterion.value" item="listitem" open="(" close=")" separator="," >
          #{listitem}
         </foreach>
        </when>
       </choose>
      </foreach>
     </trim>
    </if>
   </foreach>
  </where>
 </sql>
 <sql id="update_by_example_where_clause" >
  <where >
   <foreach collection="example.oredcriteria" item="criteria" separator="or" >
    <if test="criteria.valid" >
     <trim prefix="(" suffix=")" prefixoverrides="and" >
      <foreach collection="criteria.criteria" item="criterion" >
       <choose >
        <when test="criterion.novalue" >
         and ${criterion.condition}
        </when>
        <when test="criterion.singlevalue" >
         and ${criterion.condition} #{criterion.value}
        </when>
        <when test="criterion.betweenvalue" >
         and ${criterion.condition} #{criterion.value} and #{criterion.secondvalue}
        </when>
        <when test="criterion.listvalue" >
         and ${criterion.condition}
         <foreach collection="criterion.value" item="listitem" open="(" close=")" separator="," >
          #{listitem}
         </foreach>
        </when>
       </choose>
      </foreach>
     </trim>
    </if>
   </foreach>
  </where>
 </sql>
 <sql id="base_column_list" >
  id, name, sex, age
 </sql>
 <select id="selectbyexample" resultmap="baseresultmap" parametertype="com.sx.kak.po.studentexample" >
  select
  <if test="distinct" >
   distinct
  </if>
  <include refid="base_column_list" />
  from student
  <if test="_parameter != null" >
   <include refid="example_where_clause" />
  </if>
  <if test="orderbyclause != null" >
   order by ${orderbyclause}
  </if>
 </select>
 <select id="selectbyprimarykey" resultmap="baseresultmap" parametertype="java.lang.integer" >
  select 
  <include refid="base_column_list" />
  from student
  where id = #{id,jdbctype=integer}
 </select>
 <delete id="deletebyprimarykey" parametertype="java.lang.integer" >
  delete from student
  where id = #{id,jdbctype=integer}
 </delete>
 <delete id="deletebyexample" parametertype="com.sx.kak.po.studentexample" >
  delete from student
  <if test="_parameter != null" >
   <include refid="example_where_clause" />
  </if>
 </delete>
 <insert id="insert" parametertype="com.sx.kak.po.student" >
  insert into student (id, name, sex, 
   age)
  values (#{id,jdbctype=integer}, #{name,jdbctype=varchar}, #{sex,jdbctype=varchar}, 
   #{age,jdbctype=varchar})
 </insert>
 <insert id="insertselective" parametertype="com.sx.kak.po.student" >
  insert into student
  <trim prefix="(" suffix=")" suffixoverrides="," >
   <if test="id != null" >
    id,
   </if>
   <if test="name != null" >
    name,
   </if>
   <if test="sex != null" >
    sex,
   </if>
   <if test="age != null" >
    age,
   </if>
  </trim>
  <trim prefix="values (" suffix=")" suffixoverrides="," >
   <if test="id != null" >
    #{id,jdbctype=integer},
   </if>
   <if test="name != null" >
    #{name,jdbctype=varchar},
   </if>
   <if test="sex != null" >
    #{sex,jdbctype=varchar},
   </if>
   <if test="age != null" >
    #{age,jdbctype=varchar},
   </if>
  </trim>
 </insert>
 <select id="countbyexample" parametertype="com.sx.kak.po.studentexample" resulttype="java.lang.integer" >
  select count(*) from student
  <if test="_parameter != null" >
   <include refid="example_where_clause" />
  </if>
 </select>
 <update id="updatebyexampleselective" parametertype="map" >
  update student
  <set >
   <if test="record.id != null" >
    id = #{record.id,jdbctype=integer},
   </if>
   <if test="record.name != null" >
    name = #{record.name,jdbctype=varchar},
   </if>
   <if test="record.sex != null" >
    sex = #{record.sex,jdbctype=varchar},
   </if>
   <if test="record.age != null" >
    age = #{record.age,jdbctype=varchar},
   </if>
  </set>
  <if test="_parameter != null" >
   <include refid="update_by_example_where_clause" />
  </if>
 </update>
 <update id="updatebyexample" parametertype="map" >
  update student
  set id = #{record.id,jdbctype=integer},
   name = #{record.name,jdbctype=varchar},
   sex = #{record.sex,jdbctype=varchar},
   age = #{record.age,jdbctype=varchar}
  <if test="_parameter != null" >
   <include refid="update_by_example_where_clause" />
  </if>
 </update>
 <update id="updatebyprimarykeyselective" parametertype="com.sx.kak.po.student" >
  update student
  <set >
   <if test="name != null" >
    name = #{name,jdbctype=varchar},
   </if>
   <if test="sex != null" >
    sex = #{sex,jdbctype=varchar},
   </if>
   <if test="age != null" >
    age = #{age,jdbctype=varchar},
   </if>
  </set>
  where id = #{id,jdbctype=integer}
 </update>
 <update id="updatebyprimarykey" parametertype="com.sx.kak.po.student" >
  update student
  set name = #{name,jdbctype=varchar},
   sex = #{sex,jdbctype=varchar},
   age = #{age,jdbctype=varchar}
  where id = #{id,jdbctype=integer}
 </update>
</mapper>

2.5 编写application.yml

server:
 port: 8080
spring:
 datasource:
  driver-class-name: com.mysql.cj.jdbc.driver
  url: jdbc:mysql://localhost:3306/db0711?characterencoding=utf8&servertimezone=utc
  username: root
  password: root
mybatis:
 type-aliases-package: po
 mapper-locations: classpath:mapping/*.xml

2.6 编写jsonutils工具类

package com.sx.kak.utils;

import java.util.list;

import com.fasterxml.jackson.core.jsonprocessingexception;
import com.fasterxml.jackson.databind.javatype;
import com.fasterxml.jackson.databind.objectmapper;


public class jsonutils {

  // 定义jackson对象
  private static final objectmapper mapper = new objectmapper();

  /**
   * 将对象转换成json字符串。
   * <p>title: pojotojson</p>
   * <p>description: </p>
   * @param data
   * @return
   */
  public static string objecttojson(object data) {
  	try {
			string string = mapper.writevalueasstring(data);
			return string;
		} catch (jsonprocessingexception e) {
			e.printstacktrace();
		}
  	return null;
  }
  
  /**
   * 将json结果集转化为对象
   * 
   * @param jsondata json数据
   * @param clazz 对象中的object类型
   * @return
   */
  public static <t> t jsontopojo(string jsondata, class<t> beantype) {
    try {
      t t = mapper.readvalue(jsondata, beantype);
      return t;
    } catch (exception e) {
    	e.printstacktrace();
    }
    return null;
  }
  
  /**
   * 将json数据转换成pojo对象list
   * <p>title: jsontolist</p>
   * <p>description: </p>
   * @param jsondata
   * @param beantype
   * @return
   */
  public static <t>list<t> jsontolist(string jsondata, class<t> beantype) {
  	javatype javatype = mapper.gettypefactory().constructparametrictype(list.class, beantype);
  	try {
  		list<t> list = mapper.readvalue(jsondata, javatype);
  		return list;
		} catch (exception e) {
			e.printstacktrace();
		}
  	return null;
  }
}

2.7 编写redisutils工具类

package com.sx.kak.utils;

import java.util.list;

import com.fasterxml.jackson.core.jsonprocessingexception;
import com.fasterxml.jackson.databind.javatype;
import com.fasterxml.jackson.databind.objectmapper;


public class jsonutils {

  // 定义jackson对象
  private static final objectmapper mapper = new objectmapper();

  /**
   * 将对象转换成json字符串。
   * <p>title: pojotojson</p>
   * <p>description: </p>
   * @param data
   * @return
   */
  public static string objecttojson(object data) {
  	try {
			string string = mapper.writevalueasstring(data);
			return string;
		} catch (jsonprocessingexception e) {
			e.printstacktrace();
		}
  	return null;
  }
  
  /**
   * 将json结果集转化为对象
   * 
   * @param jsondata json数据
   * @param clazz 对象中的object类型
   * @return
   */
  public static <t> t jsontopojo(string jsondata, class<t> beantype) {
    try {
      t t = mapper.readvalue(jsondata, beantype);
      return t;
    } catch (exception e) {
    	e.printstacktrace();
    }
    return null;
  }
  
  /**
   * 将json数据转换成pojo对象list
   * <p>title: jsontolist</p>
   * <p>description: </p>
   * @param jsondata
   * @param beantype
   * @return
   */
  public static <t>list<t> jsontolist(string jsondata, class<t> beantype) {
  	javatype javatype = mapper.gettypefactory().constructparametrictype(list.class, beantype);
  	try {
  		list<t> list = mapper.readvalue(jsondata, javatype);
  		return list;
		} catch (exception e) {
			e.printstacktrace();
		}
  	return null;
  }
}

2.8 编写redisutils工具类的实现类

package com.sx.kak.utils;

import redis.clients.jedis.jedis;

/**
 * created by kak on 2020/9/17.
 */
public class singletonredisutil implements redisutils{
  private jedis jedis;
  public singletonredisutil(jedis jedis){
    this.jedis = jedis;
  }
  @override
  public void hset(string key, string filed, string value) {
    jedis.hset(key, filed, value);
  }

  @override
  public string hget(string key, string field) {
    return jedis.hget(key, field);
  }
}

2.9 配置初始化文件

package com.sx.kak.config;

import com.sx.kak.utils.singletonredisutil;
import org.springframework.beans.factory.annotation.qualifier;
import org.springframework.context.annotation.bean;
import org.springframework.context.annotation.configuration;
import redis.clients.jedis.jedis;

/**
 * created by kak on 2020/9/17.
 */
@configuration
public class redisconfig {
  @bean
  public singletonredisutil singletonredisutil(@qualifier("jedis") jedis jedis){
    singletonredisutil singletonredisutil = new singletonredisutil(jedis);
    return singletonredisutil;
  }

  @bean(name = "jedis")
  public jedis getjedis(){
    jedis jedis = new jedis("127.0.0.1",6379);
    return jedis;
  }
}

2.10 配置studentservice.java

package com.sx.kak.service;

import com.sx.kak.po.student;

import java.util.list;

/**
 * created by kak on 2020/9/17.
 */
public interface studentservice {
  public list<student> findallstudent();
}

2.11 配置studentserviceimpl.java

package com.sx.kak.service.serviceimpl;

import com.sx.kak.mapper.studentmapper;
import com.sx.kak.po.student;
import com.sx.kak.po.studentexample;
import com.sx.kak.service.studentservice;
import com.sx.kak.utils.jsonutils;
import com.sx.kak.utils.singletonredisutil;
import lombok.extern.slf4j.slf4j;
import org.springframework.beans.factory.annotation.autowired;
import org.springframework.stereotype.service;

import java.util.list;

/**
 * created by kak on 2020/9/17.
 */
@service
@slf4j
public class studentserviceimpl implements studentservice {
  @autowired(required = false)
  private studentmapper studentmapper;
  //注入自定义的redis工具
  @autowired
  private singletonredisutil redisutil;

  @override
  public list<student> findallstudent() {
    //获取redis中存出的json字符串
    string student = redisutil.hget("student", "0");
    if(student!=null){
      log.info("get student from redis");
      //json对象，封装的对象类型
      list<student> students = jsonutils.jsontolist(student, student.class);
      return students;
    }
    //创建查询模板对象
    studentexample studentexample = new studentexample();
    list<student> students = studentmapper.selectbyexample(studentexample);
    log.info("get student from db");
    try{
      //将查询的集合转化为json字符串
      string s = jsonutils.objecttojson(students);
      //放入redis中
      redisutil.hset("student","0",s);
      log.info("set data to redis");
    }catch (exception ex){
      log.info(ex.getmessage());
    }
    return students;
  }
}

2.12 编写全查展示页面

<!doctype html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
  <meta charset="utf-8"/>
  <title>学生全查页面</title>
</head>

<body>
<div id="findall">
  <table>
    <tr>
      <th>id</th>
      <th>name</th>
      <th>sex</th>
      <th>age</th>
      <th>action</th>
    </tr>
    <tr th:each="s:${students}">
      <td th:text="${s.id}"></td>
      <td th:text="${s.name}"></td>
      <td th:text="${s.sex}"></td>
      <td th:text="${s.age}"></td>
    </tr>
  </table>
</div>
</body>
</html>

2.13 编写studentcontroller

package com.sx.kak.controller;

import com.sx.kak.po.student;
import com.sx.kak.service.studentservice;
import org.springframework.beans.factory.annotation.autowired;
import org.springframework.stereotype.controller;
import org.springframework.ui.model;
import org.springframework.web.bind.annotation.requestmapping;
import org.springframework.web.bind.annotation.restcontroller;

import java.util.list;

/**
 * created by kak on 2020/9/17.
 */
@controller
public class studentcontroller {
  @autowired(required = false)
  private studentservice studentservice;

  @requestmapping("/findstudent")
  public string findallstu(model model){
    list<student> allstudent = studentservice.findallstudent();
    model.addattribute("students",allstudent);
    return "showallstudent";
  }
}

3. 结果

从打印出的日志可以看出，第一次访问是从数据库得到数据，然后存入redis中

第二次直接从redis中获取

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