mybatis 实现增删改

<?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>

    <settings>
<!--        <setting name="logImpl" value="STDOUT_LOGGING"/>-->
        <setting name="logImpl" value="LOG4J"/>
    </settings>

    <typeAliases>
        <typeAlias type="com.mybatis.pojo.User"  alias="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://localhost:3306/security?useUnicode=true&amp;characterEncoding=utf8&amp;useSSL=true"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource="com/mybatis/dao/UserMapper.xml"/>
    </mappers>

</configuration>

package com.mybatis.utils;

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 java.io.IOException;
import java.io.InputStream;

public class T {
    private static SqlSessionFactory sqlSessionFactory;
    static {
        {
            try {
                String resource = "mybatis-config.xml";
                InputStream inputStream = Resources.getResourceAsStream(resource);
                sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public static SqlSession getSqlSession(){
        return sqlSessionFactory.openSession();
    }



}

package com.mybatis.pojo;

public class User {
    private int id;
    private String username;
    private String password;


    public User() {
    }

    public User(String username, String password) {
        this.username = username;
        this.password = password;
    }

    public User(int id, String username, String password) {
        this.id = id;
        this.username = username;
        this.password = password;
    }

    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;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

<?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.mybatis.dao.UserDao">
   <select id="getUserList" resultType="User" >
       select * from users ;
   </select>

    <select id="getUserById" resultType="com.mybatis.pojo.User" parameterType="int">
        select * from users where id=#{id};
    </select>

    <insert id="addUser" parameterType="com.mybatis.pojo.User">
        insert into users (username,password) values (#{username},#{password});
    </insert>

    <update id="updateUser" parameterType="com.mybatis.pojo.User">
        update users set username=#{username},password=#{password} where id=#{id};
    </update>

    <delete id="deleteUser" parameterType="int">
        delete from users where id =#{id};
    </delete>

    <select id="getUserLimit" parameterType="map" resultType="com.mybatis.pojo.User">
        select * from users limit #{startIndex},#{pageSize} ;
    </select>

</mapper>

package com.mybatis.dao;

import com.mybatis.pojo.User;

import java.util.List;
import java.util.Map;

public interface UserDao {
    List<User> getUserList();
    User getUserById(int id);
    int addUser(User user);
    boolean updateUser(User user);
    int deleteUser(int id);
    List<User> getUserLimit(Map<String,Integer> map);
}

package com.mybatis.dao;

import com.mybatis.pojo.User;
import org.junit.Test;

import com.mybatis.utils.T;
import org.apache.ibatis.session.SqlSession;

import java.util.HashMap;
import java.util.List;

public class UserdaoTest {
    @Test
    public void testSelect(){
        SqlSession sqlSession = T.getSqlSession();
        UserDao userDao = sqlSession.getMapper(UserDao.class);

        List<User> userList = userDao.getUserList();

        for (User user : userList) {
            System.out.println(user);
        }

        sqlSession.close();

    }
    @Test
    public void testByid(){
        SqlSession sqlSession = T.getSqlSession();
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        User user = userDao.getUserById(2);
        System.out.println(user);
        sqlSession.close();
    }

    @Test
    public void testInsert(){
        SqlSession sqlSession = T.getSqlSession();
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        userDao.addUser(new User("肖2萧然","211111"));
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void testUpdate(){
        SqlSession sqlSession = T.getSqlSession();
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        userDao.updateUser(new User(1,"肖2萧然","211111"));
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void testdel(){
        SqlSession sqlSession = T.getSqlSession();
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        userDao.deleteUser(103);
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void testlimit(){
        SqlSession sqlSession = T.getSqlSession();
        UserDao userDao = sqlSession.getMapper(UserDao.class);

        HashMap<String, Integer> map = new HashMap<String, Integer>();
        map.put("startIndex",0);
        map.put("pageSize",2);

        List<User> userList = userDao.getUserLimit(map);
        for (User user : userList) {
            System.out.println(user.toString());
        }

        sqlSession.close();
    }

}