MyBatis的配置以及crud操作

 导入mybatis核心包，加入依赖包，mysql驱动包

1.加入日志配置文件Log4j.properties，放在src下（需要导入log4j-1.2.17.jar）

### \u8BBE\u7F6E### info error debuglog4j.rootLogger = debug,stdout,D,E### \u8F93\u51FA\u4FE1\u606F\u5230\u63A7\u5236\u62AC ###log4j.appender.stdout = org.apache.log4j.ConsoleAppenderlog4j.appender.stdout.Target = System.outlog4j.appender.stdout.layout = org.apache.log4j.PatternLayoutlog4j.appender.stdout.layout.ConversionPattern = [%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS} method:%l%n%m%n

2.SqlMapConfig.xml，配置mybatis的运行环境，数据源，事物等，放在src下。(需要导入mybatis-3.2.8.jar)

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd"><configuration><environments default="development"><environment id="development"><transactionManager type="JDBC" /><dataSource type="POOLED"><property name="driver" value="com.mysql.jdbc.Driver" /><property name="url" value="jdbc:mysql:///house" /><property name="username" value="root" /><property name="password" value="123456" /></dataSource></environment></environments><mappers><mapper resource="com/zucc/dao/UserMapper.xml" /></mappers></configuration><span style="font-size:18px;"></span>

3.创建数据库

4.编写User.java实体类

package com.zucc.model;public class User {private int id;private String username;private String password;private String phone;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public String getPhone() {return phone;}public void setPhone(String phone) {this.phone = phone;}@Overridepublic String toString() {return "User [id=" + id + ", username=" + username + ", password="+ password + ", phone=" + phone + "]";}}

5.编写User.xml（根据用户id(主键)查询用户信息）

<?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"><!--namspace命名空间，作用是对sql进行分类管理，sql隔离  --><mapper namespace="UserMapper"><!-- 在映射文件中可以配置很多sql语句 --><!-- 通过select标签执行数据库查询，id是标识映射文件中的sql，parameterType是指定输入参数的类型，这里是Int --><!-- #{}相当于jdbc中的占位符，名字随意 --><!-- resultType是指定sql输出结果所映射的java对象类型，select指定resultType表示将单条记录映射成java对象 --><select id="findUserById" parameterType="int" resultType="com.zucc.model.User">select * from User where id = #{id}</select></mapper>

6.需要在sqlMapConfig.xml中配置User.xml

<span style="white-space:pre"></span><mappers><mapper resource="com/zucc/dao/UserMapper.xml" /></mappers>

7.在数据库中插入一条信息

8.程序测试(可能需要导入junit-4.11.jar和hamcrest-core-1.3.jar)

package com.zucc.Test;import java.io.IOException;import java.io.InputStream;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.Test;import com.zucc.model.User;public class UserTest {@Testpublic void find() throws IOException{//mybatis配置文件String resource = "SqlMapConfig.xml";//得到配置文件流InputStream is = Resources.getResourceAsStream(resource);//创建会话工厂，传入mybatis的配置文件信息SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);//通过工厂得到SqlSessionSqlSession sqlSession = sqlSessionFactory.openSession();//通过SqlSession操作数据库//第一个参数：映射文件中statement的id,等于"namespace.statment的id"//第二个参数：指定和映射文件中所匹配的parameterType类型的参数//SqlSession.selectOne结果是与映射文件中所匹配的resultType类型的对象User user = sqlSession.selectOne("UserMapper.findUserById", 1);System.out.println(user.toString());sqlSession.close();}}

运行结果：

9.编写User.xml，添加用户信息

<span style="white-space:pre"></span><!-- 添加用户<span style="white-space:pre"></span>#{}中指定pojo的属性名，接收到pojo对象的属性值，mybatis通过ognl获取对象的属性值<span style="white-space:pre"></span> --><span style="white-space:pre"></span><insert id="addUser" parameterType="User"><span style="white-space:pre"></span>insert into user (username,password,telephone) values (#{username},#{password},#{phone})<span style="white-space:pre"></span></insert>

测试类：

<span style="white-space:pre"></span>@Test<span style="white-space:pre"></span>public void add() throws IOException {<span style="white-space:pre"></span>User user = new User();<span style="white-space:pre"></span>user.setUsername("rqq");<span style="white-space:pre"></span>user.setPassword("123");<span style="white-space:pre"></span>user.setPhone("15164897856");<span style="white-space:pre"></span>sqlSession.insert("UserMapper.addUser", user);<span style="white-space:pre"></span>sqlSession.commit();<span style="white-space:pre"></span>}

10.编写User.xml，根据用户id(主键)修改用户信息

<span></span><update id="updateUser" parameterType="User">update user <set><if test="username != null">username = #{username},</if><if test="password != null">password = #{password},</if><if test="phone != null">telephone = #{phone},</if></set> where uid=#{id}</update>

测试类：

<span style="white-space:pre"></span>@Test<span style="white-space:pre"></span>public void update() throws IOException {<span style="white-space:pre"></span>User user = new User();<span style="white-space:pre"></span>user.setUsername("rqq");<span style="white-space:pre"></span>user.setPassword("111");<span style="white-space:pre"></span>user.setPhone("1888888888");<span style="white-space:pre"></span>user.setId(6);//<span style="white-space:pre"></span>userMapper.updateUser(user);<span style="white-space:pre"></span>sqlSession.update("UserMapper.updateUser", user);<span style="white-space:pre"></span>sqlSession.commit();<span style="white-space:pre"></span>}

11.编写User.xml，根据用户id(主键)删除用户信息

<span></span><delete id="deleteUser" parameterType="int"><span style="white-space:pre"></span>delete from user where uid = #{id}<span style="white-space:pre"></span></delete>

测试类：

<span></span>@Test<span style="white-space:pre"></span>public void delete() throws IOException {//<span style="white-space:pre"></span>userMapper.deleteUser(6);<span style="white-space:pre"></span>sqlSession.delete("UserMapper.deleteUser", 6);<span style="white-space:pre"></span>sqlSession.commit();<span style="white-space:pre"></span>}