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MyBatis持久层的传统开发

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1、MyBatis持久层的传统开发-上

1.1、创建项目

**GroupId:**com.tianyi

**ArtifactId:**mb004

**Version:**1.0-SNAPSHOT

1.2、修改pom.xml加入包

<?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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.tianyi</groupId>
    <artifactId>mb004</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.11</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

1.3、创建实体类（User.java）

package com.tianyi.javabean;

import java.io.Serializable;
import java.util.Date;

public class User implements Serializable {
    private Integer id;
    private String username;
    private Date birthday;
    private String sex;
    private String address;

    public Integer getId() {
        return id;
    }

    public String getUsername() {
        return username;
    }

    public Date getBirthday() {
        return birthday;
    }

    public String getSex() {
        return sex;
    }

    public String getAddress() {
        return address;
    }

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

    public void setUsername(String username) {
        this.username = username;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", birthday=" + birthday +
                ", sex='" + sex + '\'' +
                ", address='" + address + '\'' +
                '}';
    }
}

1.4、创建持久层接口（IUserDao.java）

package com.tianyi.dao;

import com.tianyi.javabean.User;

import java.util.List;

public interface IUserDao {
    List<User> findAll();
    User findById(Integer id);
    int addUser(User u);
    int updateUser(User u);
    int deleteUser(Integer id);
    int allCount();
    List<User> findByName(String username);
}

1.5、创建持久层实现类（UserDaoImpl.java）

package com.tianyi.dao.impl;

import com.tianyi.dao.IUserDao;
import com.tianyi.javabean.User;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

import java.util.List;

public class UserDaoImpl implements IUserDao {
    private SqlSessionFactory factory;
    public UserDaoImpl(SqlSessionFactory factory) {
        this.factory = factory;
    }

    public List<User> findAll() {
        SqlSession session = factory.openSession();
        List<User> users = session.selectList("com.tianyi.dao.IUserDao.findAll");
        session.close();
        return users;
    }

    public User findById(Integer id) {
        SqlSession session =factory.openSession();
        User user = session.<User>selectOne("com.tianyi.dao.IUserDao.findById", id);
        session.close();
        return user;
    }

    public int addUser(User u) {
        SqlSession session =factory.openSession();
        int n=session.insert("com.tianyi.dao.IUserDao.addUser",u);
        session.commit();
        session.close();
        return n;
    }

    public int updateUser(User u) {
        SqlSession session =factory.openSession();
        int n=session.update("com.tianyi.dao.IUserDao.updateUser",u);
        session.commit();
        session.close();
        return n;
    }

    public int deleteUser(Integer id) {
        SqlSession session =factory.openSession();
        int n=session.delete("com.tianyi.dao.IUserDao.deleteUser",id);
        session.commit();
        session.close();
        return n;
    }

    public int allCount() {
        SqlSession session =factory.openSession();
        int n=session.selectOne("com.tianyi.dao.IUserDao.allCount");
        session.close();
        return n;
    }

    public List<User> findByName(String username) {
        SqlSession session =factory.openSession();
        List<User> users=session.selectList("com.tianyi.dao.IUserDao.findByName",username);
        session.close();
        return users;
    }
}

2、MyBatis持久层的传统开发-中

2.1、持久层的映射配置（IUserDao.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.tianyi.dao.IUserDao">
    <select id="findAll" resultType="com.tianyi.javabean.User">
        select * from user
    </select>
    <select id="findById" resultType="com.tianyi.javabean.User" parameterType="int">
        select * from user where id=#{id}
    </select>
    <insert id="addUser" parameterType="com.tianyi.javabean.User">
        <selectKey keyColumn="id" keyProperty="id" resultType="java.lang.Integer">
            select last_insert_id()
        </selectKey>
        insert into user (username,birthday,sex,address)values(#{username},#{birthday},#{sex},#{address})
    </insert>
    <update id="updateUser" parameterType="com.tianyi.javabean.User">
        update user set username=#{username},birthday=#{birthday},sex=#{sex},address=#{address} where id=#{id}
    </update>
    <delete id="deleteUser" parameterType="java.lang.Integer">
        delete from user where id=#{id}
    </delete>
    <select id="allCount" resultType="java.lang.Integer">
        select count(*) from user
    </select>
    <select id="findByName" parameterType="java.lang.String" resultType="com.tianyi.javabean.User" >
        select * from user where username like #{username}
    </select>
</mapper>

2.2、创建SqlMapConfig.xml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>
    <!-- 配置 mybatis 的环境 -->
    <environments default="mysql">
        <!-- 配置 mysql 的环境 -->
        <environment id="mysql">
            <!-- 配置事务的类型 -->
            <transactionManager type="JDBC"></transactionManager>
            <!-- 配置连接数据库的信息:用的是数据源(连接池) -->
            <dataSource type="POOLED">
                <!-- <property name="driver" value="com.mysql.jdbc.Driver"/>-->
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mb"/>
                <property name="username" value="root"/>
                <property name="password" value="root1234"/>
            </dataSource>
        </environment>
    </environments>
    <!-- 告知 mybatis 映射配置的位置 -->
    <mappers>
        <mapper resource="com/tianyi/dao/IUserDao.xml"/>
    </mappers>
</configuration>

3、MyBatis持久层的传统开发-下

3.1、编写测试类（MbTest.java）

package com.tianyi.test;

import com.tianyi.dao.IUserDao;
import com.tianyi.dao.impl.UserDaoImpl;
import com.tianyi.javabean.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 MbTest {
    private InputStream in ;
    private SqlSessionFactory factory;
    private IUserDao userDao;

   @Test
   public void findAll(){
       List<User> users = userDao.findAll();
       for(User user : users) {
           System.out.println(user);
       }
   }
   @Test
   public void findById(){
       User user=userDao.findById(8);
       System.out.println(user.toString());
   }

   @Test
   public void addUser(){
       User user=new User();
       user.setUsername("李国");
       user.setSex("男");
       user.setAddress("北京昌平");
       user.setBirthday(new Date());
       int n=userDao.addUser(user);
       System.out.println(n+":"+user.getId());
    }
    @Test
    public void updateUser(){
        User user=new User();
        user.setId(10);
        user.setUsername("李国");
        user.setSex("男");
        user.setAddress("北京昌平");
        user.setBirthday(new Date());
        int n=userDao.updateUser(user);
        System.out.println(n+":"+user.getId());
    }
    @Test
    public void deleteUser(){
       int n=userDao.deleteUser(19);
       System.out.println(n);
    }
    @Test
    public void allCount(){
        int n=userDao.allCount();
        System.out.println(n);
    }
    @Test
    public void findByName(){
       List<User> users=userDao.findByName("王%");
       for(User user:users){
           System.out.println(user);
       }
    }
   @After//在测试方法执行完成之后执行
   public void destroy() throws Exception{
       in.close();
   }
   @Before//在测试方法执行之前执行
   public void init()throws Exception {
       //1.读取配置文件
       in = Resources.getResourceAsStream("SqlMapConfig.xml");
       //2.创建构建者对象
       SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
       //3.创建 SqlSession 工厂对象
       factory = builder.build(in);
       //4、初始化userDao
       userDao=new UserDaoImpl(factory);
   }
}

注意：

pom.xml

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.9</maven.compiler.source>
<maven.compiler.target>1.9</maven.compiler.target>
</properties>

SqlMapConfig.xml

jdbc:mysql://192.168.1.123:3306/mybatis?serverTimezone=UTC
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