二.Mybatis 增删改查

时间:2021-08-03 11:27:24
Student.java
package com.pojo;

import java.util.Date;

public class Student {
int stuid;
String stuName;
int stuAge;
Date stuDate;
String stuSex;
String stuProfess;
String status;
String professName; public int getStuid() {
return stuid;
}
public void setStuid(int stuid) {
this.stuid = stuid;
}
public String getStuName() {
return stuName;
}
public void setStuName(String stuName) {
this.stuName = stuName;
}
public int getStuAge() {
return stuAge;
}
public void setStuAge(int stuAge) {
this.stuAge = stuAge;
}
public Date getStuDate() {
return stuDate;
}
public void setStuDate(Date stuDate) {
this.stuDate = stuDate;
}
public String getStuSex() {
return stuSex;
}
public void setStuSex(String stuSex) {
this.stuSex = stuSex;
}
public String getStuProfess() {
return stuProfess;
}
public void setStuProfess(String stuProfess) {
this.stuProfess = stuProfess;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
public String getProfessName() {
return professName;
}
public void setProfessName(String professName) {
this.professName = professName;
} }
  IStudentDAO.java
      
    使用合理描述参数和SQL语句返回值的接口(比如IStudentDAO.class),这样更简单,更安全的代码,便于和其他优秀框架结合
package com.dao;

import com.pojo.Student;

public interface IStudentDAO {
Student getStudentById(int stuid); void addStudent(Student stu); void delStudent(int id); void updateStudent(int id);
}

  Student.xml

    这里的 id="addStudent" 要和IStudentDAO.java接口中的方法名一致

    resultType="student"为实体类在Configuration.xml中配置的别名
<?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.IStudentDAO">
<select id="getStudentById" parameterType="int" resultType="student">
select a.*,b.professname from student a,profess b where a.stuprofess=b.proid and stuid=#{id}
</select>
<insert id="addStudent" parameterType="com.pojo.Student" keyProperty="stuid">
insert into student values(#{stuid},#{stuName},#{stuAge},#{stuDate},#{stuSex,jdbcType=CHAR},#{stuProfess})
</insert>
<delete id="delStudent" parameterType="int">
delete from student where stuid=#{id}
</delete>
<update id="updateStudent" parameterType="int">
update student set stuName=#{stuName} where stuid=#{id}
</update>
</mapper>

  测试代码 

    Test.java
package com.pojo;

import java.io.IOException;
import java.io.Reader;
import java.util.Date; 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 com.dao.IStudentDAO; public class Test {
public static void main(String[] args) throws IOException {
//读取核心的配置文件
Reader reader = Resources.getResourceAsReader("Configuration.xml");
//创建会话工厂
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(reader);
//数据库会话
SqlSession session = factory.openSession();
//查询一个对象 第一个参数字符串是由Student.xml 中的namespace+id组成
// Student stu = session.selectOne("com.dao.StudentMapper.getStudentById",5); //通过接口的方式
IStudentDAO stuDAO = session.getMapper(IStudentDAO.class);
// Student stu = stuDAO.getStudentById(5);
//
// System.out.println(stu.getStuName());
// System.out.println(stu.getStuDate());
// System.out.println(stu.getProfessName()); //测试新增
Student stu = new Student();
stu.setStuid(16);
stu.setStuName("测试新增");
stu.setStuDate(new Date());
// stu.setStuSex("1");
// stu.setStuProfess("1");
// stuDAO.addStudent(stu); //测试删除
stuDAO.delStudent(16);
session.commit();
session.close();
}
}