初始mybatis

1.

   MyBatis 本是的apache一个开源项目iBatis, 2010年这个项目由apache software foundation 迁移到了google code，

   并且改名为MyBatis 。

   iBATIS一词来源于“internet”和“abatis”的组合，是一个基于Java的持久层框架。iBATIS提供的持久层框架包括SQL Maps

   和Data Access Objects（DAO）

2.

    ① 首先你需要的工具是eclipse和安装了mysql服务器的机器

    ② 需要jar包，包括mybatis-3.2.6.jar和mysql-connector-java-5.1.7-bin.jar

　 ③ 由于进行的简单的测试，因此只需这两jar就够了。

    ④ 由于是持久化层，所以建一个 java project 即可

3.

1)数据库文件(数据库名为mc，表名为user)

CREATE TABLE user (
`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
)

采用如下的命令查看表的结构

2)创建一个实体类

package com.baba.miao.test;

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;
    }

    public User(int userId, String userName, String password, String comment) {
        super();
        this.userId = userId;
        this.userName = userName;
        this.password = password;
        this.comment = comment;
    }

    public User() {

    }

    public String toString() {
        return "User [userId=" + userId + ", userName=" + userName
                + ", password=" + password + ", comment=" + comment + "]";
    }

}

3)创建DAO层

package com.baba.miao.test;

import java.util.List;

public interface UserDao {

    public int insert(User user);

    public int update(User user);

    public int delete(String userName);

    public List<User> selectAll();

    public int countAll();

    public User findByUserName(String userName);
}

4）创建实体类的映射文件

<?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.baba.miao.test.UserDao">
    <select id="countAll" resultType="int">
        select count(*) c from user;
    </select>
    
    <select id="selectAll" resultType="com.baba.miao.test.User">
        select * from user order by userName asc
    </select>
    
    <insert id="insert" parameterType="com.baba.miao.test.User">
        insert into user(userName,password,comment) values(#{userName},#{password},#{comment})
    </insert>
    
    <update id="update" parameterType="com.baba.miao.test.User">
        update user set userName=#{userName},password=#{password},comment=#{comment} where userName=#{userName}
    </update>
    
    <delete id="delete" parameterType="int">
        delete from user where userName=#{userName}
    </delete>
    
    <select id="findByUserName" parameterType="String" resultType="com.baba.miao.test.User">
        select * from user where userName=#{userName}
    </select>
</mapper>

5)创建mybatis-config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>
    <properties resource="jdbc.properties" />
    <typeAliases>
        <package name="com.baba.miao.test"/>
    </typeAliases>
    <environments default="development">
        <environment id="development">
            <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>
        <mapper resource="com/baba/miao/test/UserDaoMapper.xml" />
    </mappers>
</configuration>

6) 创建jdbc.properties连接数据库文件

username=root
password=mmmm
url=jdbc:mysql://localhost:3306/mc
driver=com.mysql.jdbc.Driver

7）编辑单元测试文件UserDaoTest

package com.baba.miao.test;

import java.io.IOException;
import java.io.Reader;
import java.util.Iterator;
import java.util.List;

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;

public class UserDaoTest {
    @Test
    public void userDaoTest() throws IOException {
        String resource = "mybatis-config.xml";
        Reader reader = Resources.getResourceAsReader(resource);
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory factory = builder.build(reader);

        SqlSession session = factory.openSession();
        UserDao userDao = session.getMapper(UserDao.class);

        User user = new User();
        user.setUserId(1);
        user.setUserName("miaochuang");
        user.setPassword("123456");
        user.setComment("我爱你");

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

参考目录结构:

　　　　　　　　　　　　　　　　　　　　　　　　技术总结：

　　　　　　　　　　　　　　　　　　　　　　　　mybatis持久化技术

　　　　　　　　　　　　　　　　　　　　　　　　EL表达式

　　　　　　　　　　　　　　　　　　　　　　　　单元测试