JavaEE实验四关联关系映射

实验四关联关系映射

实验目的
了解数据表之间以及对象之间的三种关联关系；
掌握一对一、一对多、多对多的关联关系映射的配置。
实验内容
建学生数据库，创建院系表和学生信息表，院系表中存储院系编号，院系名称，
学生信息表中存储学生学号、姓名、性别、出生日期、籍贯、专业、所属院系等信息，在2个表中输入若干数据。
创建Java web项目，配置一对多的关联关系，插入一个学生数据，并且查询所有计算机学院的学生。

实验步骤

1、创建maven项目，在pom.xml文件中配置依赖
2、新建实体类Faculty
3、新建实体类Student
4、在resources下建db.properties、mybatis-config.xml文件。注意要在mybatis-config.xml文件中引入db.properties文件
5、在src.main.resources中建包com.mapper,包中建StudentMapper接口。
6、在mybatis-config.xml文件中注册StudentMapper.xml文件
7、在src.main.resources中建包com.mapper,包中建FacutlyMapper接口。
8、在mybatis-config.xml文件中注册FacutlyMapper.xml文件
9、在Test.java目录中创建测试类。
10、MybatisUtils
11、运行测试方法。

1、创建maven项目，在pom.xml文件中配置依赖



    4.0.0
    org.example
    sy2
    1.0-SNAPSHOT
    
        
            org.mybatis
            mybatis
            3.5.2
        
        
            mysql
            mysql-connector-java
            8.0.11
        
        
            junit
            junit
            4.12
            test
        
    
    
        8
        8
    
    
        
            
                src/main/java
                
                    ***.properties
                
                true
            
            
                src/main/resources
                
                    ***.properties
                
                true

2、新建实体类Faculty

public class Faculty {
    public Integer yxid;
    public String yxname;
    public Faculty(){}
    public Faculty(Integer yxid,String yxname){
    this.yxid=yxid;
    this.yxname=yxname;
    }
    public Integer getYxid() {
        return yxid;
    }
    public void setYxid(Integer yxid) {
        this.yxid = yxid;
    }
    public String getYxname() {
        return yxname;
    }
    public void setYxname(String yxname) {
        this.yxname = yxname;
    }
    @Override
    public String toString() {
        return "faculty{" +
                "yxid=" + yxid +
                ", yxname='" + yxname + ''' +
                '}';
    }
}

3、新建实体类Student

public class Student {
   public int xsid;
   public String xsname;
    public String sex;
    public String birthplace;
    public String birth;
    public String major;
    public String yxname;
    public List facultiesList;
    public  Student(){}
    public Student(int xsid,String xsname,String sex,String birthplace,String birth, String major, String yxname) {
        this.xsid = xsid;
        this.xsname=xsname;
        this.sex=sex;
        this.birthplace=birthplace;
        this.birth=birth;
        this.major = major;
        this.yxname=yxname;
    }
    public int getXsid() {
        return xsid;
    }
    public void setXsid(int xsid) {
        this.xsid = xsid;
    }
    public String getXsname() {
        return xsname;
    }
    public void setXsname(String xsname) {
        this.xsname = xsname;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public String getBirthplace() {
        return birthplace;
    }
    public void setBirthplace(String birthplace) {
        this.birthplace = birthplace;
    }
    public String getBirth() {
        return birth;
    }
    public void setBirth(String birth) {
        this.birth = birth;
    }
    public String getMajor() {
        return major;
    }
    public void setMajor(String major) {
        this.major = major;
    }
    public String getYxname() {
        return yxname;
    }
    public void setYxname(String yxname) {
        this.yxname = yxname;
    }
    @Override
    public String toString() {
        return "student{" +
                "xsid=" + xsid +
                ", xsname='" + xsname + ''' +
                ", sex='" + sex + ''' +
                ", birthplace='" + birthplace + ''' +
                ", birth='" + birth + ''' +
                ", major='" + major + ''' +
                ", yxname='" + yxname + ''' +
                '}';
    }
}

4、在resources下建db.properties、mybatis-config.xml文件。注意要在mybatis-config.xml文件中引入db.properties文件

//db.properties
mysql.driver=com.mysql.cj.jdbc.Driver
mysql.url=jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&characterEncoding=utf8&useUnicode=true&useSSL=false
mysql.username=root
mysql.password=123456
//mybatis-config.xml

5、在src.main.resources中建包com.mapper,包中建StudentMapper接口。

import pojo.Student;
import java.util.List;
public interface StudentMapper {
    int addStudent(Student newstudent) ;
    List findStudentByFaculty(Student newstudent);
}

6、在mybatis-config.xml文件中注册StudentMapper.xml文件






    
        insert into tb_newstudent(xsid,xsname,sex,birthplace,birth,major,yxname)
         values (#{xsid},#{xsname},#{sex},#{birthplace},#{birth},#{major},#{yxname})
    
    
    
        
        
        
        
        
        
        
        
            
            
        
    
    
    
        select u.* from tb_newstudent u,tb_faculty o where u.yxname=o.yxname and u.yxname=#{yxname};

7、在src.main.resources中建包com.mapper,包中建FacutlyMapper接口。

import pojo.Faculty;
public interface FacultyMapper {
    int addFaculty(Faculty newfaculty) ;
}

8、在mybatis-config.xml文件中注册FacutlyMapper.xml文件







    
        insert into tb_faculty(yxid,yxname) values (#{yxid},#{yxname})

9、在Test.java目录中创建测试类。

public class Test {
    @org.junit.Test
    public void facultyAddTest(){

        SqlSession session= MybatisUtils.getSqlsession();
        FacultyMapper mapper = session.getMapper(FacultyMapper.class);
        Faculty u1=new Faculty();
        u1.setYxid(104);
        u1.setYxname("外国语学院");
        int n= mapper.addFaculty(u1);
        session.commit();
        if(n>0) System.out.println("ok,新添加的学院为"+u1.yxname+"学院ID为："+u1.yxid);
        else System.out.println("error");
        //关闭session
        session.close();
    }
    @org.junit.Test
    public void studentAddTest(){

        SqlSession session= MybatisUtils.getSqlsession();
        StudentMapper mapper = session.getMapper(StudentMapper.class);
        Student u1=new Student();
        u1.setXsid(204);
        u1.setXsname("小飞机");
        u1.setSex("女");
        u1.setBirthplace("安阳");
        u1.setBirth("1999-02");
        u1.setMajor("国家英语");
        u1.setYxname("外国语学院");
        int n= mapper.addStudent(u1);
        session.commit();
        if(n>0) System.out.println("ok,新添加的学生为"+u1);
        else System.out.println("error");
        //关闭session
        session.close();
    }
    @org.junit.Test
    public void findStudentTest() {
        SqlSession session = MybatisUtils.getSqlsession();
        StudentMapper mapper = session.getMapper(StudentMapper.class);
        Student s1 = new Student();
        s1.setYxname("计算机学院");
        List students = mapper.findStudentByFaculty(s1);
        for (Student s : students) {
            System.out.println(s);
        }
        session.close();
    }
}

10、MybatisUtils

package com.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 MybatisUtils {
    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();}
}

11、运行测试方法。

1.初始数据

2.插入一个学生

3.查询所有计算机学院的学生

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