MyBatis.3.CRUD

<?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="org.mybatis.example.dao.DeptMapper">
	<select id="selectOne" parameterType="int"
		resultType="org.mybatis.example.dao.Dept">
			select * from dept where deptno=#{id}
	</select>
	<insert id="insertDept" parameterType="org.mybatis.example.dao.Dept"
	useGeneratedKeys="true" keyProperty="dept">
		insert into dept(dname,loc)
		values(
			   #{dname,jdbcType=VARCHAR},
			   #{loc,jdbcType=VARCHAR})
	</insert> 
	<update id="updateDept" parameterType="org.mybatis.example.dao.Dept">
		update dept set dname=#{dname},loc=#{loc}
					where deptno=#{deptno}
	</update>
	<delete id="deleteDept" parameterType="java.lang.Integer">
		delete from dept where deptno=#{id}
	</delete>
</mapper>

JAVA就业套餐课：https://edu.csdn.net/combo/detail/1230

package org.mybatis.example.dao;

public interface DeptMapper {
	public Dept selectOne(int id);
	public int insertDept(Dept dept);
	public int updateDept(Dept dept);
	public int deleteDept(int id);
}

 

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;
import org.mybatis.example.dao.Dept;
import org.mybatis.example.dao.DeptMapper;


public class Test2 {
	public static void main(String[] args) throws IOException {
		String resource="mybatisConfig.xml";
		Reader reader=Resources.getResourceAsReader(resource);
		SqlSessionFactory sqlMapper=new SqlSessionFactoryBuilder().build(reader);
		
		SqlSession session=sqlMapper.openSession();
		
		try {
			DeptMapper mapper=session.getMapper(DeptMapper.class);
			//1.查询
//			Dept dept=mapper.selectOne(2);
//			System.out.println(dept.getDname());
			//2.插入操作
			Dept dept=new Dept();
			dept.setDname("张沅湲");
			dept.setLoc("郑州");
			mapper.insertDept(dept);
			session.commit();//实现增加 修改 删除
			//3.更新操作;
//			Dept dept=new Dept();
//			dept.setDeptno(3);
//			dept.setDname("张沅湲");
//			dept.setLoc("湖南");
//			mapper.updateDept(dept);
//			session.commit();
			//4.删除操作;
//			int i=mapper.deleteDept(3);
//			session.commit();
//			System.out.println(i);
		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			session.close();
		}
		
	}
}

复杂的查询，在项目开发中，可以使用一个工具类来封装这些复杂的步骤：

 

package org.mybatis.example.dao;

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 SqlSessionFactoryUtil {
	private static SqlSessionFactory factory;
	public SqlSessionFactoryUtil() {}
	static{
		Reader reader=null;
		
		try {
			reader=Resources.getResourceAsReader("mybatisConfig.xml");
			factory=new SqlSessionFactoryBuilder().build(reader);
		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			try {
				if(reader!=null)reader.close();
			} catch (Exception e2) {
				e2.printStackTrace();
			}
		}
	}
	
	public static SqlSession getSqlSession(){
		return factory.openSession();
	}
}

DeptMapper接口的完全代码：

 

 

package org.mybatis.example.dao;

import java.util.List;

public interface DeptMapper {
	public Dept selectOne(int id);
	public int insertDept(Dept dept);
	public int updateDept(Dept dept);
	public int deleteDept(int id);
	public List<Dept>selectAllDepts();
	public List<Dept>selectByCriteria(String deptName);
}

1.查询所有部门信息参考代码;

 

 

<select id="selectAllDepts" resultType="org.mybatis.example.dao.Dept" >
		select deptno,dname,loc from dept
	</select>

测试代码；

 

 

import java.util.List;

import org.apache.ibatis.session.SqlSession;
import org.mybatis.example.dao.Dept;
import org.mybatis.example.dao.DeptMapper;
import org.mybatis.example.dao.SqlSessionFactoryUtil;

public class Test3 {
	public static void main(String[] args) {
		SqlSession session=SqlSessionFactoryUtil.getSqlSession();
		try {
			DeptMapper mapper=session.getMapper(DeptMapper.class);
			List<Dept>depts=mapper.selectAllDepts();
			for(Dept dept:depts){
				System.out.println("部门名称:"+dept.getDname());
			}
		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			session.close();
		}
	}
}

2.按条件查询，映射文件做以下修改，新增条件为模糊查询方法：

 

 

<!-- 按条件查询 -->
	<select id="selectByCriteria" parameterType="java.lang.String"
		resultType="org.mybatis.example.dao.Dept">
		select deptno,dname,loc from dept
		where dname like '%${_parameter}%'	
	</select>

测试代码

 

 

import java.util.List;

import org.apache.ibatis.session.SqlSession;
import org.mybatis.example.dao.Dept;
import org.mybatis.example.dao.DeptMapper;
import org.mybatis.example.dao.SqlSessionFactoryUtil;

//按照条件进行查询;
public class Test4 {
	public static void main(String[] args) {
		SqlSession session=SqlSessionFactoryUtil.getSqlSession();
		try {
			DeptMapper mapper=session.getMapper(DeptMapper.class);
			List<Dept>depts=mapper.selectByCriteria("网络部");
			
			for(Dept dept:depts){
				System.out.println("部门名称:"+dept.getDname());
			}
		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			session.close();
		}
	}
}