mybatis简单运用（基于Annotation）

恒晖瑶

　　

本文主要介绍了如何使用mybatis进行简单的数据库操作。本文使用的是mybatis3.05。
1.创建数据库表（User表）

CREATE TABLE `NewTable` (
`userId`  bigint(20) NOT NULL AUTO_INCREMENT ,
`userName`  varchar(30) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL ,
`password`  varchar(80) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL ,
`comment`  varchar(250) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL ,
PRIMARY KEY (`userId`),
UNIQUE INDEX `UQ_User_userName` (`userName`) USING BTREE
)


2. 创建实体类

package com.mybatis.config;

public class User {
private int userId;
private String userName;
private String password;
private String comment;
public int getUserId() {
return userId;
    }
public void setUserId(int userId) {
this.userId = userId;
    }
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 getComment() {
return comment;
    }
public void setComment(String comment) {
this.comment = comment;
    }
}


3.创建数据访问接口

package com.mybatis.config;

import java.util.List;

import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

public interface UserDao {
    @Insert("insert into user(userName,password,comment) values(#{userName},#{password},#{comment})")
public int insert(User user);

    @Update("update user set userName=#{userName},password=#{password},comment=#{comment} where userName=#{userName}")
public int update(User user);

    @Delete("delete from user where userName=#{userName}")
public int delete(String userName);

    @Select("select * from user order by userName asc")
public List<User> selectAll();

    @Select("select count(*) c from user;")
public int countAll();

    @Select("select * from user where userName=#{userName}")
public User findByUserName(String userName);
}


4.编写mybatis配置文件

<?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>
<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://localhost:3306/hlp?useUnicode=true&amp;characterEncoding=UTF-8&amp;zeroDateTimeBehavior=convertToNull" />
<property name="username" value="root" />
<property name="password" value="1234" />
</dataSource>
</environment>
</environments>
</configuration>


5.数据库访问辅助类

package com.mybatis.config;

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;

public class DbHelper {
private static DbHelper dbHelper=null;
private static SqlSessionFactory sqlSessionFactory=null;
private DbHelper(){
        String resource = "MyBatis-Configuration.xml";
        Reader reader;
try {
            reader = Resources.getResourceAsReader(resource);
            sqlSessionFactory =new SqlSessionFactoryBuilder().build(reader);
            sqlSessionFactory.getConfiguration().addMapper(UserDao.class);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
public SqlSession getSqlSession(){
return sqlSessionFactory.openSession();
    }
public static DbHelper getInstance(){
if(dbHelper==null)
            dbHelper = new DbHelper();
return dbHelper;
    }
}


6.编写测试代码

package com.mybatis.config;

import java.util.Iterator;
import java.util.List;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

public class UserDaoTest {
    @Test
public void userDaoTest() throws Exception
    {
        SqlSession session = DbHelper.getInstance().getSqlSession();
        UserDao userDao = session.getMapper(UserDao.class);

        User user = new User();
        user.setUserName("hongye");
        user.setPassword("123456");
        user.setComment("备注");

        userDao.insert(user);
        System.out.println("记录条数："+userDao.countAll());

        List<User> users = userDao.selectAll();
        Iterator<User> iter = users.iterator();
while(iter.hasNext()){
            User u = iter.next();
            System.out.println("用户名："+u.getUserName()+"密码："+u.getPassword());
        }

        user.setComment("comment");
        userDao.update(user);
        User u = userDao.findByUserName("hongye");
        System.out.println(u.getComment());

        userDao.delete("hongye");
        System.out.println("记录条数："+userDao.countAll());

        session.commit();
        session.close();
    }
}