Mybatis之入门实例

tonwei139

• MyBatis 是什么
  

　　MyBatis是一款一流的支持自定义 SQL、存储过程和高级映射的持久化框架。MyBatis几乎消除了所有的JDBC代码，也基本不需要手工去设置参数和获取检索结果。MyBatis能够使用简单的XML格式或者注解进行来配置，能够映射基本数据元素、Map接口和POJOs（普通java 对象）到数据库中的记录。

• MyBatis 开发配置
  

　　mybatis-3.1.1.jar
　　mysql-connector-java-5.0.4-bin.jar
　　junit-4.8.1.jar（可选：用于测试）

• MyBatis 入门实例
  

　　第一个MyBatis项目目录：

　　开发流程：
　　1）在src目录下创建mybatis的配置文件mybatis-config.xml，在该文件中完成和数据库的连接设置操作

<?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" />
<typeAliases>
<typeAlias type="cn.mybatis.model.User" alias="User" />
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="${driver}" />
<property name="username" value="${username}" />
<property name="password" value="${password}" />
<property name="url" value="${url}" />
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="cn/mybatis/model/User.xml" />
</mappers>
</configuration>

username=root
password=mysql
url=jdbc:mysql://localhost:3306/test
driver=com.mysql.jdbc.Driver
　　2）创建数据库表并生成相应的实体类

DROP TABLE IF EXISTS `t_user`;
CREATE TABLE `t_user` (
`id` int(10) NOT NULL auto_increment,
`name` varchar(20) default NULL COMMENT '姓名',
`nickname` varchar(20) default NULL COMMENT '昵称',
`password` varchar(10) default NULL COMMENT '用户密码',
PRIMARY KEY  (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

package cn.mybatis.model;
public class User {
private int id;
private String name;
private String nickname;
private String password;
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 String getNickname() {
return nickname;
}
public void setNickname(String nickname) {
this.nickname = nickname;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
@Override
public String toString() {
return "User [id=" + id + ", name=" + name + ", nickname=" + nickname
+ ", password=" + password + "]";
}
}

　　3）生成实体类的mapper映射xml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="cn.mybatis.model.User">
<insert id="add" parameterType="User">
insert into t_user
(name,password,nickname) value
(#{name},#{password},#{nickname})
</insert>
<update id="update" parameterType="User">
update t_user set
name=#{name},nickname=#{nickname},password=#{password} where id=#{id}
</update>
<delete id="delete" parameterType="int">
delete from t_user where
id=#{id}
</delete>
<select id="load" parameterType="int" resultType="User">
select * from t_user where
id=#{id}
</select>
</mapper>
　　4）创建获取SQlSession的Util类

package cn.mybatis.util;
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;
public class MyBatisUtil {
private static SqlSessionFactory factory;
static {
try {
InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
factory = new SqlSessionFactoryBuilder().build(is);
} catch (IOException e) {
e.printStackTrace();
}
}
public static SqlSession createSession() {
return factory.openSession();
}
public static void closeSession(SqlSession session) {
if (session != null)
session.close();
}
}

　　5）Junit方式测试SqlSession完成对数据库的操作

package cn.mybatis.test;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import cn.mybatis.model.User;
import cn.mybatis.util.MyBatisUtil;
public class MybatisTest01 {
@Test
public void testAdd() {
SqlSession session = null;
try {
session = MyBatisUtil.createSession();
User u = new User();
u.setName("Tom");
u.setNickname("Tomy");
u.setPassword("123");
session.insert(User.class.getName() + ".add", u);
session.commit();
} catch (Exception e) {
e.printStackTrace();
session.rollback();
} finally {
MyBatisUtil.closeSession(session);
}
}
@Test
public void testUpdate() {
SqlSession session = null;
try {
session = MyBatisUtil.createSession();
User u = new User();
u.setId(1);
u.setName("Tom");
u.setNickname("Tomy");
u.setPassword("123456");
session.update(User.class.getName() + ".update", u);
session.commit();
} catch (Exception e) {
e.printStackTrace();
session.rollback();
} finally {
MyBatisUtil.closeSession(session);
}
}
@Test
public void testSelect() {
SqlSession session = null;
try {
session = MyBatisUtil.createSession();
User u = (User) session.selectOne(User.class.getName() + ".load", 1);
System.out.println("name: " + u.getName());
} finally {
MyBatisUtil.closeSession(session);
}
}
@Test
public void testDelete() {
SqlSession session = null;
try {
session = MyBatisUtil.createSession();
session.delete(User.class.getName() + ".delete", 1);
session.commit();
} catch (Exception e) {
e.printStackTrace();
session.rollback();
} finally {
MyBatisUtil.closeSession(session);
}
}
}