SpringBoot无废话入门04：MyBatis整合

1.parent引入及pom配置

        首先，如果要支持mybatis，那么我们就应该引入mybatis的starter。同时，由于连接本身还需要用jdbc的connetor和连接池，所以一并需要引入这些依赖。如下是一个完整的的最简pom，

<?xml version="1.0" encoding="utf-8"?>

<project xmlns="http://maven.apache.org/pom/4.0.0" xmlns:xsi="http://www.w3.org/2001/xmlschema-instance" xsi:schemalocation="http://maven.apache.org/pom/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

  <modelversion>4.0.0</modelversion>

  <packaging>war</packaging>

  <parent>

    <groupid>org.springframework.boot</groupid>

    <artifactid>spring-boot-starter-parent</artifactid>

    <version>2.1.3.release</version>

  </parent>

  <name>testboot01</name>

  <groupid>com.zuikc</groupid>

  <artifactid>testboot01</artifactid>

  <version>1.0-snapshot</version>

  <dependencies>

      <!--jsp支持, servlet 依赖. -->

      <dependency>

          <groupid>javax.servlet</groupid>

          <artifactid>javax.servlet-api</artifactid>

          <scope>provided</scope>

      </dependency>

      <dependency>

          <groupid>javax.servlet</groupid>

          <artifactid>jstl</artifactid>

      </dependency>

      <!-- tomcat 的支持.-->

      <dependency>

          <groupid>org.springframework.boot</groupid>

          <artifactid>spring-boot-starter-tomcat</artifactid>

      </dependency>

      <dependency>

          <groupid>org.apache.tomcat.embed</groupid>

          <artifactid>tomcat-embed-jasper</artifactid>

          <scope>provided</scope>

      </dependency>

      <dependency>

          <groupid>mysql</groupid>

          <artifactid>mysql-connector-java</artifactid>

      </dependency>

      <dependency>

          <groupid>org.apache.tomcat</groupid>

          <artifactid>tomcat-dbcp</artifactid>

          <version>7.0.47</version>

      </dependency>

      <dependency>

          <groupid>org.apache.tomcat</groupid>

          <artifactid>tomcat-dbcp</artifactid>

          <version>7.0.47</version>

      </dependency>

      <dependency>

          <groupid>org.mybatis.spring.boot</groupid>

          <artifactid>mybatis-spring-boot-starter</artifactid>

          <version>1.3.2</version>

      </dependency>

    <dependency>

      <groupid>org.springframework.boot</groupid>

      <artifactid>spring-boot-starter-web</artifactid>

    </dependency>

  </dependencies>

  <build>

    <plugins>

      <plugin>

        <groupid>org.springframework.boot</groupid>

        <artifactid>spring-boot-maven-plugin</artifactid>

      </plugin>

    </plugins>

  </build>

</project>

2.配置初始化

        首先我们需要将数据库连接配置到文件中，比如prop.properties，

jdbc.driver=com.mysql.jdbc.driver

jdbc.url=jdbc:mysql://localhost:3306/test01?useunicode=true&characterencoding=utf8

jdbc.username=root

jdbc.password=root

jdbc.maxactive=2335

jdbc.maxidel=120

jdbc.maxwait=100

        然后，用java配置的方式将其引入到代码中，创建datasourceconfiguration，

package com.zuikc.config;

import org.apache.tomcat.dbcp.dbcp.basicdatasource;

import org.springframework.beans.factory.annotation.value;

import org.springframework.context.annotation.bean;

import org.springframework.context.annotation.configuration;

import org.springframework.context.annotation.propertysource;

@configuration

//这个注解导入刚才增加的jdbc配置文件

@propertysource("classpath:prop.properties")

public class datasourceconfiguration {

    @value("${jdbc.driver}")

    private string driver;

    @value("${jdbc.url}")

    private string url;

    @value("${jdbc.username}")

    private string username;

    @value("${jdbc.password}")

    private string password;

    @value("${jdbc.maxactive}")

    private int maxactive;

    @value("${jdbc.maxidel}")

    private int maxidel;

    @value("${jdbc.maxwait}")

    private long maxwait;

    @bean

    public basicdatasource datasource(){

        basicdatasource datasource = new basicdatasource();

        datasource.setdriverclassname(driver);

        datasource.seturl(url);

        datasource.setusername(username);

        datasource.setpassword(password);

        datasource.setmaxactive(maxactive);

        datasource.setmaxidle(maxidel);

        datasource.setmaxwait(maxwait);

        datasource.setvalidationquery("select 1");

        datasource.settestonborrow(true);

        return datasource;

    }

}

        接着，增加mybatis配置，

package com.zuikc.config;

import javax.sql.datasource;

import org.apache.ibatis.session.sqlsessionfactory;

import org.mybatis.spring.sqlsessionfactorybean;

import org.mybatis.spring.sqlsessiontemplate;

import org.springframework.beans.factory.annotation.autowired;

import org.springframework.context.annotation.bean;

import org.springframework.context.annotation.configuration;

import org.springframework.jdbc.datasource.datasourcetransactionmanager;

import org.springframework.transaction.platformtransactionmanager;

import org.springframework.transaction.annotation.enabletransactionmanagement;

import org.springframework.transaction.annotation.transactionmanagementconfigurer;

@configuration

//加上这个注解，使得支持事务

@enabletransactionmanagement

public class mybatisconfig implements transactionmanagementconfigurer {

    @autowired

    private datasource datasource;

    @override

    public platformtransactionmanager annotationdriventransactionmanager() {

        return new datasourcetransactionmanager(datasource);

    }

    @bean(name = "sqlsessionfactory")

    public sqlsessionfactory sqlsessionfactorybean() {

        sqlsessionfactorybean bean = new sqlsessionfactorybean();

        bean.setdatasource(datasource);

        try {

            return bean.getobject();

        } catch (exception e) {

            e.printstacktrace();

            throw new runtimeexception(e);

        }

    }

    @bean

    public sqlsessiontemplate sqlsessiontemplate(sqlsessionfactory sqlsessionfactory) {

        return new sqlsessiontemplate(sqlsessionfactory);

    }

}

        注意上面的sqlsessionfactory这个bean。

        然后需要配置mybatis配置文件的路径，这个配置需要与上面的配置分开来写，因为它们有着一个先后顺序，

package com.zuikc.config;

import org.mybatis.spring.mapper.mapperscannerconfigurer;

import org.springframework.boot.autoconfigure.autoconfigureafter;

import org.springframework.context.annotation.bean;

import org.springframework.context.annotation.configuration;

@configuration

// 因为这个对象的扫描，需要在mybatisconfig的后面注入，所以加上下面的注解

@autoconfigureafter(mybatisconfig.class)

public class mybatismapperscannerconfig {

    @bean

    public mapperscannerconfigurer mapperscannerconfigurer() {

        mapperscannerconfigurer mapperscannerconfigurer = new mapperscannerconfigurer();

        //获取之前注入的beanname为sqlsessionfactory的对象

        mapperscannerconfigurer.setsqlsessionfactorybeanname("sqlsessionfactory");

        //指定xml配置文件的路径

        mapperscannerconfigurer.setbasepackage("com.zuikc.dao");

        return mapperscannerconfigurer;

    }

}

3.三层架构

        先创建最底层的dao接口，如下：

package com.zuikc.dao;

import java.util.list;

import java.util.map;

import org.apache.ibatis.annotations.mapper;

import org.apache.ibatis.annotations.select;

@mapper

public interface testdao {

    @select("select * from tbl_user;")

    public list<map<string,object>> find();

}

        接着创建service，

package com.zuikc.service;

import com.zuikc.dao.testdao;

import org.springframework.stereotype.service;

import javax.annotation.resource;

import java.util.list;

import java.util.map;

@service

public class testservice {

    @resource

    testdao dao;

    public list<map<string,object>> find(){

        list<map<string,object>> users = dao.find();

        return users;

    }

}

        然后是controller，

package com.zuikc.controller;

import com.zuikc.dao.testdao;

import com.zuikc.service.testservice;

import org.springframework.beans.factory.annotation.autowired;

import org.springframework.stereotype.controller;

import org.springframework.web.bind.annotation.requestmapping;

import javax.annotation.resource;

import java.text.simpledateformat;

import java.util.date;

import java.util.list;

import java.util.map;

@controller

public class studentcontroller {

    @autowired

    testservice service;

    @requestmapping(value = {"test01"})

    public string view(map<string, object> map) {

        list<map<string,object>> users = service.find();

        for (map<string, object> user : users) {

            for (map.entry<string, object> entry : user.entryset()) {

                system.out.println("key = " + entry.getkey() + ", value = " + entry.getvalue());

            }

        }

        system.out.println(users.size());

        map.put("name", "zuikc.com");

        map.put("date", new simpledateformat("yyyy-mm-dd hh:mm:ss").format(new date()));

        return "views/test01";

    }

}

        经过上面的创建之后，我们的代码结构是这样的，

        执行之，

        注意了，如果你已经忘记了如何启动mysql，那么，下面就是命令哦：

        sudo bin/mysqld_safe --user=mysql &

4.事务支持

        第一步，导入jdbc依赖，

      <dependency>

          <groupid>org.springframework.boot</groupid>

          <artifactid>spring-boot-starter-jdbc</artifactid>

      </dependency>

        注意，有了这个依赖，springboot会自动注入datasourcetransactionmanager。 

        接着，直接在service中添加@transactional注解就能支持事务啦。本文不再赘述，大家自己尝试一下吧。

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