Mybatis-Lesson2

先写一个实体，用来做各种操作

实现序列化接口，便于对象转为二进制进行传输（序列化反序列化）

import java.io.Serializable;
import java.util.List;

public class QueryVo implements Serializable {

    private static final long serialVersionUID = 1L;
    //
    private User user;
    List<Integer> idsList;
    Integer[] ids;
    
    public List<Integer> getIdsList() {
        return idsList;
    }
    public void setIdsList(List<Integer> idsList) {
        this.idsList = idsList;
    }
    public Integer[] getIds() {
        return ids;
    }
    public void setIds(Integer[] ids) {
        this.ids = ids;
    }
    public User getUser() {
        return user;
    }
    public void setUser(User user) {
        this.user = user;
    }
}

动态SQL

UserMapper.xml中的<if>标签、1=1用法、<where>标签（作用：去掉第一个and）

SQL片段（公共的片段，复用）

<sql id="selector">
    select * from user
</sql>

<!--    根据性别和名字查询用户  where 可以去掉第一个前ANd   -->
 <select id="selectUserBySexAndUsername" parameterType="User" resultType="User">
    <include refid="selector"/>
    <where>
        <if test="sex != null and sex != ''">
             and sex = #{sex} 
        </if>
        <if test="username != null and username != ''">
             and username = #{username}
        </if>
    </where>
 </select>

foreach（你的sql中某个参数输入的条件是一个数组）

 <!-- 多个ID (1,2,3)  collection="list/array/vo"  list对应List<Integer>参数  array对应Integer[]参数  -->
 <select id="selectUserByIds" parameterType="QueryVo" resultType="User">
    <include refid="selector"/>
    <where>
        <foreach collection="list" item="id" separator="," open="id in (" close=")">
            #{id}
        </foreach>
    </where>
 </select>

关联查询（连接查询）

实体Orders

public class Orders  implements Serializable{
    
    private static final long serialVersionUID = 1L;

    private Integer id;
    private Integer userId;
    private String number;
    private Date createtime;
    private String note;
    
    //附加对象  用户对象
    private User user;

一对一

    <!-- 
        //一对一关联 查询  以订单为中心 关联用户
    public List<Orders> selectOrders();
     -->
     <resultMap type="Orders" id="order">
         <result column="id" property="id"/>
         <result column="user_id" property="userId"/>
         <result column="number" property="number"/>
         <!-- 一对一 -->
         <association property="user" javaType="User">
             <id column="user_id" property="id"/>
             <result column="username" property="username"/>
         </association>
     </resultMap>
     <select id="selectOrders" resultMap="order">
         SELECT 
         o.id,
         o.user_id, 
         o.number,
         o.createtime,
         u.username 
         FROM orders o 
         left join user u 
         on o.user_id = u.id
     </select>

实体User

public class User implements Serializable {

    private static final long serialVersionUID = 1L;
    private Integer id;
    private String username;// 用户姓名
    private String sex;// 性别
    private Date birthday;// 生日
    private String address;// 地址
    
    //附加对象List
    private List<Orders> ordersList;

一对多

<!-- 
         //一对多关联
    public List<User> selectUserList(); -->
    <resultMap type="User" id="user">
        <id column="user_id" property="id"/>
        <result column="username" property="username"/>
        <!-- 一对多 -->
        <collection property="ordersList" ofType="Orders">
            <id column="id" property="id"/>
            <result column="number" property="number"/>
        </collection>
    </resultMap>
    <select id="selectUserList" resultMap="user">
        SELECT 
         o.id,
         o.user_id, 
         o.number,
         o.createtime,
         u.username 
         FROM user u
         left join orders o 
         on o.user_id = u.id
    </select>

Mybatis与Spring整合

SqlSessionFactory对象应该放到spring容器中作为单例存在。
传统dao的开发方式中，应该从spring容器中获得sqlsession对象。
Mapper代理形式中，应该从spring容器中直接获得mapper的代理对象。
数据库的连接以及数据库连接池事务管理都交给spring容器来完成。

jar包

spring的jar包
Mybatis的jar包
Spring+mybatis的整合包。
Mysql的数据库驱动jar包。
数据库连接池的jar包。

aopalliance-1.0.jar
asm-3.3.1.jar
aspectjweaver-1.6.11.jar
cglib-2.2.2.jar
commons-dbcp-1.2.2.jar
commons-logging-1.1.1.jar
commons-pool-1.3.jar
javassist-3.17.1-GA.jar
jstl-1.2.jar
junit-4.9.jar
log4j-1.2.17.jar
log4j-api-2.0-rc1.jar
log4j-core-2.0-rc1.jar
mybatis-3.2.7.jar
mybatis-spring-1.2.2.jar
mysql-connector-java-5.1.7-bin.jar
slf4j-api-1.7.5.jar
slf4j-log4j12-1.7.5.jar
spring-aop-4.1.3.RELEASE.jar
spring-aspects-4.1.3.RELEASE.jar
spring-beans-4.1.3.RELEASE.jar
spring-context-4.1.3.RELEASE.jar
spring-context-support-4.1.3.RELEASE.jar
spring-core-4.1.3.RELEASE.jar
spring-expression-4.1.3.RELEASE.jar
spring-jdbc-4.1.3.RELEASE.jar
spring-jms-4.1.3.RELEASE.jar
spring-messaging-4.1.3.RELEASE.jar
spring-tx-4.1.3.RELEASE.jar
spring-web-4.1.3.RELEASE.jar
spring-webmvc-4.1.3.RELEASE.jar

jar包

配置文件

sqlMapConfig.xml

<?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>
    <!-- 设置别名 -->
    <typeAliases>
        <!-- 2. 指定扫描包，会把包内所有的类都设置别名，别名的名称就是类名，大小写不敏感 -->
        <package name="com.itheima.mybatis.pojo" />
    </typeAliases>
    
    <mappers>
        <package name="com.itheima.mybatis.mapper"/>
    </mappers>

</configuration>

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
    http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd 
    http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
    http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.0.xsd">

    <context:property-placeholder location="classpath:db.properties"/>
    
    <!-- 数据库连接池 -->
    <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>
    
    <!-- Mybatis的工厂 放到spring容器-->
    <bean id="sqlSessionFactoryBean" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <!-- 核心配置文件的位置 -->
        <property name="configLocation" value="classpath:sqlMapConfig.xml"/>
    </bean>
    
    <!-- Dao原始Dao 放到spring容器-->
    <bean id="userDao" class="com.itheima.mybatis.dao.UserDaoImpl">
        <property name="sqlSessionFactory" ref="sqlSessionFactoryBean"/>
    </bean>
    <!-- Mapper动态代理开发 放到spring容器-->
    <bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
        <property name="sqlSessionFactory" ref="sqlSessionFactoryBean"/>
        <property name="mapperInterface" value="com.itheima.mybatis.mapper.UserMapper"/>
    </bean>
    
    <!-- Mapper动态代理开发   扫描  放到spring容器-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!-- 基本包 -->
        <property name="basePackage" value="com.itheima.mybatis.mapper"/>
    </bean>
    
</beans>

db.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf-8
jdbc.username=root
jdbc.password=root

log4j.properties

# 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

原始dao开发

import org.mybatis.spring.support.SqlSessionDaoSupport;

/**
 * 原始Dao开发
 * @author lx
 *
 */
public class UserDaoImpl extends SqlSessionDaoSupport implements UserDao{

    //声明工厂
    public void insertUser(){
//        this.getSqlSession().insert(arg0, arg1)
    }
    
}

spring容器接手dao（条件是给它一个sqlSessionFactory）

<!-- Dao原始Dao -->
    <bean id="userDao" class="com.itheima.mybatis.dao.UserDaoImpl">
        <property name="sqlSessionFactory" ref="sqlSessionFactoryBean"/>
    </bean>

spring容器管理mapper（只要你给它两个东西：sqlSessionFactory和mapperInterface）

<!-- Mapper动态代理开发 -->
    <bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
        <property name="sqlSessionFactory" ref="sqlSessionFactoryBean"/>
        <property name="mapperInterface" value="com.itheima.mybatis.mapper.UserMapper"/>
    </bean>

给spring的东西其实就是红色（为了说明问题）

@Test
public void testMapper() throws Exception {
        //加载核心配置文件
        String resource = "sqlMapConfig.xml";
        InputStream in = Resources.getResourceAsStream(resource);
        //创建SqlSessionFactory
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
        //创建SqlSession
        SqlSession sqlSession = sqlSessionFactory.openSession();
        
        //SqlSEssion帮我生成一个实现类  （给接口）
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);

        User user = userMapper.findUserById(10);
        System.out.println(user);
 }

测试

指定mapper的位置

<mappers>
        <package name="com.itheima.mybatis.mapper"/>
    </mappers>

    @Test
    public void testMapper() throws Exception {
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserMapper mapper = ac.getBean(UserMapper.class);
//        UserMapper mapper = (UserMapper) ac.getBean("userMapper");
        User user = mapper.findUserById(10);
        System.out.println(user);
    }

动态代理开发增强版

    <!-- Mapper动态代理开发   扫描 -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!-- 基本包 -->
        <property name="basePackage" value="com.itheima.mybatis.mapper"/>
    </bean>

逆向工程

（这个目前在idea的springboot开发中很EZ，这些工具类，一个一个积累）

完了这个测试类有点意思

    @Test
    public void testMapper() throws Exception {
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
        
        UserMapper userMapper = ac.getBean(UserMapper.class);
        UserExample example = new UserExample();
        String username = "明";
        example.createCriteria().andSexEqualTo("1").andUsernameLike("%" + username + "%");
        
        example.setOrderByClause("id desc");
        
        int countByExample = userMapper.countByExample(example);
        System.out.println(countByExample);
        
        User user = userMapper.selectByPrimaryKey(10);
        System.out.println(user);
        
        List<User> users = userMapper.selectByExample(example);
        for (User user2 : users) {
            System.out.println(user2.getId());
        }
    }

有空再看看gacl的mybatis篇

posted @ 2020-05-20 21:06 夜雨秋池阅读(140) 评论(0) 编辑收藏举报

会员力量，点亮园子希望

刷新页面返回顶部

夜雨秋池

狡猾点！勤快点！

Mybatis-Lesson2