MyBatis 入门(一)--建立数据库连接及基本操作

一、 数据库建表

CREATE TABLE `user` (  `userId` int(11) NOT NULL AUTO_INCREMENT,  `UserName` varchar(45) NOT NULL,  `UserEmail` varchar(200) NOT NULL,  PRIMARY KEY (`userId`),  UNIQUE KEY `userId_UNIQUE` (`userId`)) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8;

二、maven配置

     <dependencies>        <dependency>            <groupId>org.mybatis</groupId>            <artifactId>mybatis</artifactId>            <version>3.2.6</version>        </dependency>        <dependency>            <groupId>junit</groupId>            <artifactId>junit</artifactId>            <version>4.12</version>            <scope>test</scope>        </dependency>        <dependency>            <groupId>c3p0</groupId>            <artifactId>c3p0</artifactId>            <version>0.9.1.2</version>        </dependency>        <dependency>            <groupId>mysql</groupId>            <artifactId>mysql-connector-java</artifactId>            <version>6.0.2</version>        </dependency>    </dependencies>

三、mybasit 配置

1. jdbc.properties 配置 数据连接

driver=com.mysql.cj.jdbc.Driverurl=jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf8&useSSL=true&serverTimezone=UTCusername=mybatispassword=mybatismaxActive= 50

1. mybatis-config.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>    <properties resource="jdbc.properties" />       <environments default="dev">        <environment id="dev">            <transactionManager type="JDBC" />            <dataSource type="POOLED">                <property name="driver" value="${driver}" />                <property name="url" value="${url}" />                <property name="username" value="${username}" />                <property name="password" value="${password}" />            </dataSource>        </environment>    </environments>    <mappers>    </mappers></configuration>

四、建立User的POJO

package com.elements.user.model;public class User {    public int getUserId() {        return userId;    }    public void setUserId(int userId) {        this.userId = userId;    }    public String getUserName() {        return UserName;    }    public void setUserName(String userName) {        UserName = userName;    }    public String getUserEmail() {        return UserEmail;    }    public void setUserEmail(String userEmail) {        UserEmail = userEmail;    }    private int userId;    private String UserName;    private String UserEmail;    @Override    public String toString() {        return "User [userId=" + userId + ", UserName=" + UserName                + ", UserEmail=" + UserEmail + "]";    }}

五、 UserMapper配置文件

• UserMapper 配置文件

<?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.elements.user.mapper">  <resultMap type="com.elements.user.model.User" id="usermap">        <id column="userId" property="userId"/>        <result column="UserName" property="UserName"/>        <result column="UserEmail" property="UserEmail"/>    </resultMap>    <select id="getAllUser" resultMap="usermap">        select * from mybatis.user    </select>    <select id="getUserById" resultMap="usermap" parameterType="String">        select * from mybatis.user where userId= #{userId}    </select>    <insert id="insert" parameterType="com.elements.user.model.User">     insert into mybatis.user (UserName, UserEmail) values (          #{UserName}, #{UserEmail}     )    </insert>    <update id="update" parameterType="com.elements.user.model.User">     update mybatis.user set UserName=#{UserName},     UserEmail=#{UserEmail}     where userId= #{userId}    </update>    <delete id="delete" parameterType="String">     delete mybatis.user where userId= #{userId}    </delete></mapper>

• 将配置文件加入mybatis-config.xml的 mappers中

    <mappers>    <mapper resource="com/elements/user/mapper/UserMapper.xml" />    </mappers>

六、 建立测试类

public class TestUser {    @Test    public void TestSelectAll() throws IOException {        //        String resource = "mybatis-config.xml";        InputStream inputStream = Resources.getResourceAsStream(resource);        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder()                .build(inputStream);        SqlSession session = sqlSessionFactory.openSession();        try {            List<User> userlist = session                    .selectList("com.elements.user.mapper.getAllUser");            System.out.print(userlist);        }catch(Exception e){            System.out.print(e);        }        finally {            session.close();        }    }    @Test    public void TestSelect() throws IOException {        //        String resource = "mybatis-config.xml";        InputStream inputStream = Resources.getResourceAsStream(resource);        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder()                .build(inputStream);        SqlSession session = sqlSessionFactory.openSession();        try {            User user = (User) session.selectOne(                    "com.elements.user.mapper.getUserById", "1");            System.out.print(user);        } finally {            session.close();        }    }    @Test    public void TestInsert() throws IOException {        String resource = "mybatis-config.xml";        InputStream inputStream = Resources.getResourceAsStream(resource);        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder()                .build(inputStream);        SqlSession session = sqlSessionFactory.openSession();        try {            User user = new User();            user.setUserName("abc");            user.setUserEmail("aaaaa");            session.update("com.elements.user.mapper.insert", user);            session.commit();        } finally {            session.close();        }    }    @Test    public void TestUpdate() throws IOException {        String resource = "mybatis-config.xml";        InputStream inputStream = Resources.getResourceAsStream(resource);        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder()                .build(inputStream);        SqlSession session = sqlSessionFactory.openSession();        try {            User user = new User();            user.setUserId(7);            user.setUserName("aaaaa");            user.setUserEmail("aaaaa");            session.update("com.elements.user.mapper.update", user);            session.commit();        } finally {            session.close();        }    }}

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项目代码下载：http://pan.baidu.com/s/1kUGD61D