mybatis（4）：增删改查（insert+select+update+delete）（上集）

学会掌握了mybatis的增删改查方法，应用在mysql上。

1、Employeemapper.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="com.DAO.EmpDAO">
<!-- 
namespace:名称空间;指定为接口的全类名
id：唯一标识
resultType：返回值类型
#{id}：从传递过来的参数中取出id值

public Employee getEmpById(Integer id);
 -->
	<select id="getEmpById" resultType="com.Emp.Employee">
		select id,lastname,email,gender from employee where id = #{id}
	</select>
	
	<select id="getEmp" resultType="com.Emp.Employee">
		select * from employee 
	</select>
	
	<insert id="addEmp" parameterType="com.Emp.Employee">
		insert into employee (lastname,email,gender) 
		values (#{lastname},#{email},#{gender})
	</insert>
	
	<update id="updateEmp">
		update employee set lastname = #{lastname},email=#{email},gender=#{gender} 
		where id=#{id}
	</update>
	
	<delete id="deleteEmp">
		delete from employee where id=#{id}
	</delete>
</mapper>

2、接口编程，所以写了一个接口EmpDAO.java：

package com.DAO;

import com.Emp.Employee;

public interface EmpDAO {
	public Employee getEmpById(Integer id);
	public boolean addEmp (Employee emp);
	public void updateEmp (Employee emp);
	public void deleteEmp (Integer id);
	public Employee getEmp();
	
}

3、对应的数据模型为Employee.java：

package com.Emp;

public class Employee {
	private int id;
	private String lastname;
	private String email;
	private String gender;
	
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getLastname() {
		return lastname;
	}
	public void setLastname(String lastname) {
		this.lastname = lastname;
	}
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	public String getGender() {
		return gender;
	}
	public void setGender(String gender) {
		this.gender = gender;
	}
	
	@Override
	public String toString() {
		return "Employee [id=" + id + ", lastname=" + lastname + ", email=" + email + ", gender=" + gender + "]";
	}
	
	public Employee( String lastname, String email, String gender) {
		super();
		this.lastname = lastname;
		this.email = email;
		this.gender = gender;
	}
	
	public Employee( int id ,String lastname, String email, String gender) {
		super();
		this.id = id;
		this.lastname = lastname;
		this.email = email;
		this.gender = gender;
	}
	
	public Employee() {}
	
	
}

4、测试文件EmployeeTest，进行单元测试：

package com.Emp;

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

import com.DAO.EmpDAO;

public class EmployeeTest {
	public SqlSessionFactory getSqlSessionFactory() throws IOException {
		//1.sessionfactory 由文件读取数据流确定
		String resource = "mybatis-config.xml";
		InputStream inputStream = Resources.getResourceAsStream(resource);
		return new SqlSessionFactoryBuilder().build(inputStream);
	}
	@Test
	public void test() throws IOException {
		//2.sessionfactory创建session
		SqlSessionFactory sqlsessionfactory = getSqlSessionFactory();
		SqlSession session =sqlsessionfactory.openSession();
		Employee emp = new Employee("mmb","123@qq.com","1");		
		try{
			//3.session的getmapper，创建映射对象
			EmpDAO empmapper = (EmpDAO) session.getMapper(EmpDAO.class);
			List<Employee> aa = new ArrayList<Employee>();
			Employee e = new Employee(16,"abc","123@qq.com","1"); 
			
			//insert + commit
//			System.out.println(empmapper.addEmp(emp));
//			session.commit();
			
			//select
//			e = empmapper.getEmpById(16);
//			System.out.println("result:"+e.toString());	
			
			//update + commit
//			 emp = new Employee(16,"abc","123@qq.com","1");
//			 empmapper.updateEmp(emp);
//			 session.commit();
			
			//delete + commit
//			empmapper.deleteEmp(16);
//			session.commit();
			
		}finally{
			session.close();
		}			
		
	}

}