Mybatis入门例子以及Mybatis-Spring整合 - 程序制造者

一.Mybatis

项目目录：

log4j.properties文件负责打印日志的配置

# Global logging configuration
log4j.rootLogger=DEBUG, stdout
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

SQLMapConfig.xml文件配置，主要配置mybatis的数据库连接配置，以及指定扫描mapper配置文件（用于调用方法和数据库查询语句的匹配），内容如下：

<?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>
    <!-- 和spring整合后 environments配置将废除-->
    <environments default="development">
        <environment id="development">
            <!-- 使用jdbc事务管理，事务控制由mybatis-->
            <transactionManager type="JDBC" />
            <!-- 数据库连接池,由mybatis管理-->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis001?characterEncoding=utf-8" />
                <property name="username" value="root" />
                <property name="password" value="root" />
            </dataSource>
        </environment>
    </environments>

    <mappers>
　　　　　<!--扫描mapper包下的所有mapper-->
        <package name="mapper"/>   
    </mappers>

</configuration>

UserObjectMapper.java和UserObjectMapper.xml文件分别用于定义调用方法的接口和配置调用方法对应的sql语句。文件名必须相同，切在同一个文件夹下，才能使用后续SQLSession.getMapper方法构建出UserObjectMapper的实例，进行接口内方法的调用。

UserObjectMapper.java内容：

package mapper;

import pojo.User;
import pojo.UserQueryVo;

import java.io.IOException;
import java.util.List;

/**
 * Created by 01467835 on 2017/9/22.
 */
public interface UserObjectMapper{


    public List<User> findUserList(UserQueryVo userQueryVo) throws IOException;

    public List<User> findUserListById(UserQueryVo userQueryVo) throws IOException;


}

UserObjectMapper.xml文件的内容：

<?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="mapper.UserObjectMapper">

    <sql id="query_user_where">
        <if test="user!=null">
            <if test="user.sex!=null and user.sex!=''">
                AND user.sex = #{user.sex}
            </if>
            <if test="user.address!=null and user.address!=''">
                AND user.address LIKE '%${user.address}%'
            </if>
        </if>
    </sql>

    <sql id="query_id_where">
        <if test="ids!=null">
            <foreach collection="ids" item="user_id" open="AND (" close=")" separator="or">
                id=#{user_id}
            </foreach>
        </if>
        AND user.sex = sex.sex_id
    </sql>
    
    <resultMap id="UserSexResultMap" type="pojo.User">
        <id column="id" property="id"/>
        <result column="username" property="username"/>
        <result column="birthday" property="birthday"/>
        <result column="address" property="address"/>
        
        <association property="sexName" javaType="pojo.Sex">
            <id column="sex_id" property="sexId"/>
            <result column="sex_name" property="sexName"/>
        </association>
    </resultMap>

    
    <select id="findUserList" parameterType="pojo.UserQueryVo" resultType="pojo.User">
        SELECT * from USER 
        <where>
            <include refid="query_user_where"></include>
        </where>
    </select>
    <select id="findUserListById" parameterType="pojo.UserQueryVo" resultMap="UserSexResultMap">
        SELECT * FROM USER,SEX
        <where>
            <include refid="query_id_where"></include>
        </where>
    </select>

    
</mapper>
mapper中的返回方式有resultType和resultMap两种，前者直接返回数据类型，后者可以定义一个ResultMap进行更多的逻辑设计。包括if的分支逻辑，foreach的循环逻辑，association的一对一关联查询，collection的一对多关联查询等等。

MaybatisTest.java测试文件，主要用户指定配置文件，创建SQLSessionFactory，编写测试用例等，内容如下

package MybatisTest;

import mapper.UserObjectMapper;
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.Before;
import org.junit.Test;
import pojo.User;
import pojo.UserQueryVo;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

/**
 * Created by 01467835 on 2017/9/22.
 */
public class MybatisTest {

    private SqlSessionFactory sqlSessionFactory;

    @Before
    public void setup() throws IOException{
        String resource = "SqlMapConfig.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
    }

    @Test
    public void findUserList() throws IOException{
        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserObjectMapper userObjectMapper = sqlSession.getMapper(UserObjectMapper.class);
        UserQueryVo userQueryVo = new UserQueryVo();

        User user = new User();
        user.setSex(1);
        user.setAddress("2");
        userQueryVo.setUser(user);

        List<Integer> ids = new ArrayList<>();
        ids.add(1);
        ids.add(3);
        userQueryVo.setIds(ids);

        List<User> userList = userObjectMapper.findUserListById(userQueryVo);
        System.out.println(userList);
    }

}pojo中主要是一些实体类，sex，User，UserQureyVo等，其中UserQueryVo中主要存储补充到查询语句中的条件信息。内容如下：
UserQueryVo.java的内容：

package pojo;

import java.util.List;

/**
 * Created by 01467835 on 2017/9/22.
 */
public class UserQueryVo {
    private User user;
    private List<Integer> ids;    //如果你要查询某些id对用的用户信息，可以将id存在这个list下，传入到UserObjectMapper.java中进行对应的查询

    public List<Integer> getIds() {
        return ids;
    }

    public void setIds(List<Integer> ids) {
        this.ids = ids;
    }

    public User getUser() {
        return user;
    }

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



二、Mybatis和Spring整合
spring中提供了dataSource的方式连接数据库，废除了SqlMapConfig中的environment的方式，增加了spring的配置文件applicationContext.xml，内容如下：

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:util="http://www.springframework.org/schema/util"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
      http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
      http://www.springframework.org/schema/mvc
      http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd
      http://www.springframework.org/schema/context
      http://www.springframework.org/schema/context/spring-context-3.2.xsd
      http://www.springframework.org/schema/aop
      http://www.springframework.org/schema/aop/spring-aop-3.2.xsd
      http://www.springframework.org/schema/tx
      http://www.springframework.org/schema/tx/spring-tx-3.2.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd">


    <!-- 加载配置文件 -->
    <context:property-placeholder location="classpath:db.properties" />

    <!-- 数据源，使用dbcp -->
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
          destroy-method="close">
        <property name="driverClassName" value="${jdbc.driver}" />
        <property name="url" value="${jdbc.url}" />
        <property name="username" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
        <property name="maxActive" value="10" />
        <property name="maxIdle" value="5" />
    </bean>

    <!-- sqlSessinFactory -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!-- 加载mybatis的配置文件 -->
        <property name="configLocation" value="mybatis/SqlMapConfig.xml" />
        <!-- 数据源 -->
        <property name="dataSource" ref="dataSource" />
    </bean>

    <!-- 逐个进行mapper接口的配置-->
    <bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
        <property name="mapperInterface" value="com.haier.ssm.mapper.UsersMapper"/>
        <property name="sqlSessionFactory" ref="sqlSessionFactory"/>
    </bean>

    <!-- 此方法在jdk8与spring3使用时会报错，切换到JDK7可以以使用包扫描功能
    <bean id="userMapper" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.haier.ssm.mapper"/>
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
    </bean>
    -->
</beans>

SQLMapConfig.xml中只需要声明一下扫描mapper的包，内容如下：

<?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>
    <mappers>
        <package name="com.haier.ssm.mapper"/>
    </mappers>
</configuration>

在test文件中调用spring整合mybatis之后的方法，内容如下

package com.haier.ssm.test;

import com.haier.ssm.dao.UserDao;
import com.haier.ssm.mapper.UsersMapper;
import com.haier.ssm.po.User;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * Created by 01467835 on 2017/9/25.
 */
public class UserDaoImplTest {
    private ApplicationContext applicationContext;

    @Before
    public void setup() throws Exception{
        applicationContext = new ClassPathXmlApplicationContext("classpath:spring/applicationContext.xml");
    }

    @Test
    public void testFindUserById() throws Exception{
        UsersMapper userMapper = (UsersMapper)applicationContext.getBean("userMapper");
        User user = userMapper.findUserById(1);
        System.out.println(user);
    }
}

发表于 2017-09-27 13:35 程序制造者阅读(234) 评论(0) 编辑收藏举报