Mybatis04—注解开发实现CRUD以及实现一对一、一对多及多对多复杂关系映射

mybatis常用注解说明

@Insert:实现新增
@Update:实现更新
@Delete:实现删除
@Select:实现查询
@Result:实现结果集封装
@Results:可以与
@Result一起使用，封装多个结果集
@ResultMap:实现引用
@Results定义的封装
@One:实现一对一结果集封装
@Many:实现一对多结果集封装
@SelectProvider: 实现动态SQL映射
@CacheNamespace:实现注解二级缓存的使用

Mybatis注解实现CRUD

User实体类：

package com.review.domain;

import java.util.*;

public class User {
    private Integer userId;
    private String userName;
    private Date userBirthday;
    private String userSex;
    private String userAddress;

    public Integer getUserId() {
        return userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public Date getUserBirthday() {
        return userBirthday;
    }

    public void setUserBirthday(Date userBirthday) {
        this.userBirthday = userBirthday;
    }

    public String getUserSex() {
        return userSex;
    }

    public void setUserSex(String userSex) {
        this.userSex = userSex;
    }

    public String getUserAddress() {
        return userAddress;
    }

    public void setUserAddress(String userAddress) {
        this.userAddress = userAddress;
    }

    @Override
    public String toString() {
        return "User{" +
                "userId=" + userId +
                ", username='" + userName + '\'' +
                ", userBirthday=" + userBirthday +
                ", userSex='" + userSex + '\'' +
                ", userAddress='" + userAddress + '\'' +
                '}';
    }
}

IUserDao持久层接口：

package com.review.dao;

import com.review.domain.User;
import org.apache.ibatis.annotations.*;

import java.util.List;


public interface IUserDao {
    /**
     * 查询所有用户
     */
    @Select("select * from user")
    @Results(id = "userMap",value = {
            @Result(id = true,column = "id",property = "userId"),
            @Result(column = "username",property = "userName"),
            @Result(column = "birthday",property = "userBirthday"),
            @Result(column = "sex",property = "userSex"),
            @Result(column = "address",property = "userAddress")
    })
    List<User> findAll();

    /**
     * 根据id查询
     */
    @Select("select *from user where id=#{uid}")
    @ResultMap("userMap")
    User findById(Integer userId);

    /**
     * 保存用户
     */
    @Insert("insert into user(username,birthday,sex,address) values (#{userName},#{userBirthday},#{userSex},#{userAddress})")
    @SelectKey(keyColumn = "id",keyProperty = "userId",before = false,resultType =Integer.class,statement = {" select last_insert_id()"})
    @ResultMap("userMap")
    void saveUser(User user);

    /**
     * 用户更新
     */
    @Update("update user set username=#{userName},birthday=#{userBirthday},sex=#{userSex}, address=#{userAddress} where id=#{userId}")
    @ResultMap("userMap")
    void updateUser(User user);

    /**
     * 删除用户
     */
    @Delete("delete from user where id=#{uid}")
    @ResultMap("userMap")
    void deleteUser(Integer userId);
    /**
     * 用户模糊查询
     */
    @Select("select * from user where username like #{username}")
    @ResultMap("userMap")
    List<User> findByName(String username);
    /**
     * 使用聚合函数查询总记录条数
     */
    @Select("select count(*) from user")
    //@ResultMap("userMap")
    int findTotal();
}

SqlMapConfig 配置文件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

    <properties resource="db.properties"></properties>

    <environments default="mysql">
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${db.driver}"/>
                <property name="url" value="${db.url}"/>
                <property name="username" value="${db.username}"/>
                <property name="password" value="${db.password}"/>
            </dataSource>
        </environment>
    </environments>
    <!-- 告知mybatis映射配置的位置 -->
    <mappers>
        <mapper class="com.review.dao.IUserDao"/>
    </mappers>
</configuration>

测试类：

package com.review.test;


import com.review.dao.IUserDao;
import com.review.domain.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.InputStream;
import java.util.Date;
import java.util.List;

public class MybatisTest {
    private InputStream in;
    private SqlSessionFactoryBuilder builder;
    private SqlSessionFactory factory;
    private SqlSession session;
    private IUserDao userDao;

    @Test
    public void testFindAll() throws Exception {
        List<User> users = userDao.findAll();
        for(User user:users){
            System.out.println(user);
        }
    }

    @Test
    public void testFindOne() throws Exception {
        User user = userDao.findById(48);
        System.out.println(user);
    }

    @Test
    public void testSave() throws Exception {
        User user = new User();
        user.setUserName("周杰伦");
        user.setUserAddress("*省台北市");
        user.setUserSex("男");
        user.setUserBirthday(new Date());
        userDao.saveUser(user);
        System.out.println(user);
    }

    @Test
    public void testUpdateUser() throws Exception {
        User user = userDao.findById(42);
        user.setUserName("小王");
        userDao.updateUser(user);
        System.out.println(user);
    }

    @Test
        public void testDeleteUser() throws Exception {
            userDao.deleteUser(62);
    }

    @Test
    public void testFindByName() throws Exception {
        List<User> users = userDao.findByName("%王%");
        for (User user : users) {
            System.out.println(user);
        }
    }

    @Test
    public void testFindTotal() throws Exception {
        int res = userDao.findTotal();
        System.out.println(res);
    }

    @Before
    public void init() throws Exception {
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        builder = new SqlSessionFactoryBuilder();
        factory = builder.build(in);
        session = factory.openSession();
        userDao = session.getMapper(IUserDao.class);

    }

    @After
    public void destroy() throws Exception {
        session.commit();
        session.close();
        in.close();
    }
}

注解实现一对一复杂关系映射

添加Account实体类及User实体类：

public class Account implements Serializable {
    private Integer id;
    private Integer uid;
    private double money;
//    一个账户对应一个用户
    private User user;

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public Integer getUid() {
        return uid;
    }

    public void setUid(Integer uid) {
        this.uid = uid;
    }

    public double getMoney() {
        return money;
    }

    public void setMoney(double money) {
        this.money = money;
    }

    @Override
    public String toString() {
        return "Account{" +
                "id=" + id +
                ", uid=" + uid +
                ", money=" + money +
                '}';
    }
}

public class User implements Serializable {
    private Integer userId;
    private String userName;
    private Character userSex;
    private String userAddress;
    private Date userBirthday;

    public Integer getUserId() {
        return userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public Character getUserSex() {
        return userSex;
    }

    public void setUserSex(Character userSex) {
        this.userSex = userSex;
    }

    public String getUserAddress() {
        return userAddress;
    }

    public void setUserAddress(String userAddress) {
        this.userAddress = userAddress;
    }

    public Date getUserBirthday() {
        return userBirthday;
    }

    public void setUserBirthday(Date userBirthday) {
        this.userBirthday = userBirthday;
    }

    @Override
    public String toString() {
        return "User{" +
                "userId=" + userId +
                ", userName='" + userName + '\'' +
                ", userSex='" + userSex + '\'' +
                ", userAddress='" + userAddress + '\'' +
                ", userBirthday=" + userBirthday +
                '}';
    }
}

添加账户和用户的持久层接口并使用注解配置：

public interface IAccountDao {
    /**
     * 查询所有账户信息
     * @return
     */
    @Select("select * from account")
    @Results(id = "accountMap",value = {
            @Result(id = true,column = "ID",property = "id"),
            @Result(column = "UID",property = "uid"),
            @Result(column = "MONEY",property = "money"),
            @Result(column = "UID",property = "user",one = @One(select = "com.review.dao.IUserDao.findById",fetchType = FetchType.EAGER))
    })
    List<Account> findAll();
}

public interface IUserDao {
    /**
     * 根据id查询一个用户
     * @return
     */
    @Select("select * from user where id = #{uid} ")
    @Results(id = "userMap", value = {
            @Result(id = true, column = "id", property = "userId"),
            @Result(column = "username", property = "userName"),
            @Result(column = "sex", property = "userSex"),
            @Result(column = "address", property = "userAddress"),
            @Result(column = "birthday", property = "userBirthday")})
    User findById(Integer userId);
}

SqlMapConfig 配置文件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

    <properties resource="db.properties"></properties>
<!--    <typeAliases>-->
<!--        <package name="com.review.domain"></package>-->
<!--    </typeAliases>-->

    <environments default="mysql">
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${db.driver}"/>
                <property name="url" value="${db.url}"/>
                <property name="username" value="${db.username}"/>
                <property name="password" value="${db.password}"/>
            </dataSource>
        </environment>
    </environments>
    <!-- 告知mybatis映射配置的位置 -->
    <mappers>
        <mapper class="com.review.dao.IAccountDao"/>
        <mapper class="com.review.dao.IUserDao"/>
    </mappers>
</configuration>

测试类：

@Test
    public void testFindAll() {
        List<Account> accounts = accountDao.findAll();
        for(Account account : accounts){
            System.out.println("----每个账户的信息-----");
            System.out.println(account);
            System.out.println(account.getUser());
        }
    }

控制台打印结果：

注解实现一对多复杂关系映射

添加User实体类及Account实体类：

public class User implements Serializable {
    private Integer userId;
    private String userName;
    private Character userSex;
    private String userAddress;
    private Date userBirthday;
    //    一个用户可能对应多个账户
    private List<Account> accounts;

    public List<Account> getAccounts() {
        return accounts;
    }

    public void setAccounts(List<Account> accounts) {
        this.accounts = accounts;
    }

    public Integer getUserId() {
        return userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public Character getUserSex() {
        return userSex;
    }

    public void setUserSex(Character userSex) {
        this.userSex = userSex;
    }

    public String getUserAddress() {
        return userAddress;
    }

    public void setUserAddress(String userAddress) {
        this.userAddress = userAddress;
    }

    public Date getUserBirthday() {
        return userBirthday;
    }

    public void setUserBirthday(Date userBirthday) {
        this.userBirthday = userBirthday;
    }

    @Override
    public String toString() {
        return "User{" +
                "userId=" + userId +
                ", userName='" + userName + '\'' +
                ", userSex='" + userSex + '\'' +
                ", userAddress='" + userAddress + '\'' +
                ", userBirthday=" + userBirthday +
                '}';
    }
}

public class Account implements Serializable {
    private Integer id;
    private Integer uid;
    private double money;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public Integer getUid() {
        return uid;
    }

    public void setUid(Integer uid) {
        this.uid = uid;
    }

    public double getMoney() {
        return money;
    }

    public void setMoney(double money) {
        this.money = money;
    }

    @Override
    public String toString() {
        return "Account{" +
                "id=" + id +
                ", uid=" + uid +
                ", money=" + money +
                '}';
    }
}

添加用户和账户的持久层接口并使用注解配置：

public interface IUserDao {
    /**
     * 查询所有用户
     * @return
     */
    @Select("select * from user")
    @Results(id = "userMap", value = {
            @Result(id = true, column = "id", property = "userId"),
            @Result(column = "username", property = "userName"),
            @Result(column = "sex", property = "userSex"),
            @Result(column = "address", property = "userAddress"),
            @Result(column = "birthday", property = "userBirthday"),
            @Result(column = "id",property = "accounts",many= @Many(select = "com.review.dao.IAccountDao.findById",fetchType = FetchType.EAGER))
    })
    List<User> findAll();
}

public interface IAccountDao {
    /**
     * 查询所有账户信息
     * @return
     */
    @Select("select * from account where UID=#{id}")
    @Results(id = "accountMap",value = {
            @Result(id = true,column = "ID",property = "id"),
            @Result(column = "UID",property = "uid"),
            @Result(column = "MONEY",property = "money")
    })
    List<Account> findById();
}

测试类：

@Test
    public void testFindAll() {
        List<User> users = userDao.findAll();
        for (User user:users){
            System.out.println();
            System.out.println("----每个用户的信息----");
            System.out.println(user);
            System.out.println(user.getAccounts());
        }
    }

控制台打印结果：

mybatis基于注解的二级缓存

在SqlMapConfig中开启二级缓存支持：

<!--    配置二级缓存-->
    <settings>
        <setting name="cacheEnabled" value="true"/>
    </settings>

在持久层接口中使用注解配置二级缓存：

@CacheNamespace(blocking=true)//mybatis基于注解方式实现配置二级缓存 
public interface IUserDao {}