Mybatis简单的入门之增删改查

一般的过程例如以下

1、加入Mybatis所须要的包，和连接数据库所需的包

2、配置mybatis-config.xml文件

3、配置与pojo相应的映射文件

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>

<typeAliases><!--类型别名-->

<typeAlias alias="User" type="com.iss.pojo.User" />

</typeAliases>





<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://127.0.0.1:3306/test?useUnicode=true&amp;characterEncoding=UTF-8" />

<property name="username" value="root" />

<property name="password" value="root" />

</dataSource>

</environment>

</environments>





<mappers>

<mapper resource="com/iss/pojo/User.xml" /><!--映射文件的路径-->

</mappers>

</configuration>

pojo实体类

package com.iss.pojo;





public class User {

private int id;





private String name;





public int getId() {

return id;

}





public void setId(int id) {

this.id = id;

}





public String getName() {

return name;

}





public void setName(String name) {

this.name = name;

}





public User(int id, String name) {

super();

this.id = id;

this.name = name;

}





public User() {

super();

}





}

User.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="User"><!--映射的命名空间也就是在mybatis中配置的别名-->

<select id="selectUser" parameterType="int" resultType="User"><!--在mybatis-config.xml中为类型起了别名-->

<![CDATA[

        select * from user where id = #{id}]]><!--查询的是表名不是对象-->

</select>

<insert id="insertUser" parameterType="User">



<![CDATA[insert into user

value(#{id},#{name})]]>





</insert>

<delete id="deleteUser" parameterType="int">

delete from user where

id=#{id}





</delete>

<update id="updateUser" parameterType="User">

update user set

name=#{name} where id=#{id}

</update>

</mapper>

Mybatis工具类

Mybatis工具类

package com.iss.util;





import java.io.IOException;

import java.io.Reader;





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 com.sun.org.apache.xpath.internal.operations.Gte;





public class MybatisUtil {





private static SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();//类似于Hibernate中Configration





private static SqlSessionFactory sqlSessionFactory;//类似于Hibernate中SessionFactory





// 静态初始化块配置文件在类执行时仅仅载入一次

static {





String resource = "mybatis-config.xml";

Reader reader = null;

try {

reader = Resources.getResourceAsReader(resource);

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}





sqlSessionFactory = builder.build(reader);

}





private MybatisUtil() {

// TODO Auto-generated constructor stub

}





public static SqlSessionFactoryBuilder getBuilder() {

return builder;

}





public static void setBuilder(SqlSessionFactoryBuilder builder) {

MybatisUtil.builder = builder;

}





      

public static SqlSessionFactory getSqlSessionFactory() {

return sqlSessionFactory;

}





public static void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) {

MybatisUtil.sqlSessionFactory = sqlSessionFactory;

}





// 获得sqlSession对象类似于Hibernate中的session

public static SqlSession getSqlSession() {

SqlSession sqlSession = sqlSessionFactory != null ? sqlSessionFactory

.openSession() : null;

return sqlSession;

}





public static void closeSession() {

SqlSession sqlSession = getSqlSession();

if (sqlSession != null) {

sqlSession.close();

}

}





}

UserService

package com.iss.service;





import org.apache.ibatis.session.SqlSession;





import com.iss.pojo.User;

import com.iss.util.MybatisUtil;





public class UserService {





public static User selectUser(int id) {

SqlSession sqlSession = MybatisUtil.getSqlSession();

User user = sqlSession.selectOne("selectUser", 1);

MybatisUtil.closeSession();

return user;

}





public static void insertUser(int id, String name) {





User user = new User();

user.setId(id);

user.setName(name);





SqlSession sqlSession = MybatisUtil.getSqlSession();

sqlSession.insert("insertUser", user);

sqlSession.commit();

MybatisUtil.closeSession();

}





public static void updateUser(int id, String name) {

User user = new User();

user.setId(id);

user.setName(name);





SqlSession sqlSession = MybatisUtil.getSqlSession();

sqlSession.update("updateUser", user);

sqlSession.commit();

MybatisUtil.closeSession();





}





public static void deleteUser(int id) {

SqlSession sqlSession = MybatisUtil.getSqlSession();

sqlSession.delete("deleteUser", id);

sqlSession.commit();

MybatisUtil.closeSession();

}





}

TestUser

package com.iss.test;





import com.iss.pojo.User;

import com.iss.service.UserService;





public class TestUser {





public static void main(String[] args) {





UserService.insertUser(3, "world");

User user = UserService.selectUser(2);

System.out.println(user.getName());

UserService.updateUser(1, "wdy");

System.out.println(UserService.selectUser(2).getName());





UserService.deleteUser(2);

}

}

总结Hibernate 和Mybatis非常相似

基本的差别

Hibernate的映射文件是对表的映射

Mybatis的映射文件是对表操作的一种映射