用戶表的增刪改查
package com.it.pojo;

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

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;
}

public String getGender() {
    return gender;
}

public void setGender(String gender) {
    this.gender = gender;
}

public String getAddr() {
    return addr;
}

public void setAddr(String addr) {
    this.addr = addr;
}

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

}
package com.it.mapper;

import com.it.pojo.User;

import java.util.List;

public interface UserMapper {

List<User> selectAll();

User selectById(int id);

}

<select id="selectById" resultType="user">
    select * from tb_user where id = #{id};
</select>

import com.it.mapper.UserMapper;
import com.it.pojo.User;
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;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class UserMapperTest {

@Test
public  void testSelectAll() throws IOException {
    //1.加載mybatis核心配置文件，獲取SqlSessionFactory
    String resource = "mybatis-config.xml";
    InputStream inputStream = Resources.getResourceAsStream(resource);
    SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

    //2.獲取SqlSession對象，用他來執行sql語句
    SqlSession sqlSession = sqlSessionFactory.openSession();

    //3.執行sql語句
    //獲取UserMapper接口的代理對象
    UserMapper userMapper = sqlSession.getMapper(UserMapper.class);

    //執行方法
    List<User> users = userMapper.selectAll();
    System.out.println(users);

    //4.釋放資源
    sqlSession.close();
}

@Test
public  void testSelectById() throws IOException {
    //接受參數
    int id = 1;
    //1.加載mybatis核心配置文件，獲取SqlSessionFactory
    String resource = "mybatis-config.xml";
    InputStream inputStream = Resources.getResourceAsStream(resource);
    SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

    //2.獲取SqlSession對象，用他來執行sql語句
    SqlSession sqlSession = sqlSessionFactory.openSession();

    //3.執行sql語句
    //獲取UserMapper接口的代理對象
    UserMapper userMapper = sqlSession.getMapper(UserMapper.class);

    //執行方法
    User user = userMapper.selectById(id);
    System.out.println(user);

    //4.釋放資源
    sqlSession.close();
}

}