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javaee 实现数据库查询操作mybatis

作者:互联网

 

 

项目路径和数据库如上

1.pom.xml

<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>

<dependencies>
<!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.49</version>
</dependency>
<!-- https://mvnrepository.com/artifact/junit/junit -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>

2.db.properties
jdbc.driver = com.mysql.jdbc.Driver
jdbc.url = jdbc:mysql://localhost:3306/chapter03?useUnicode=true&characterEncoding=utf-8
jdbc.username = root
jdbc.password = 123

3.mybatis-config.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<properties resource="db.properties"/>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driver}" />
<property name="url" value="${jdbc.url}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
</dataSource>
</environment>
</environments>
<mappers>
<package name="com.ssm.mybatis.dao"/>
</mappers>
</configuration>

4.IStuClassMapper
package com.ssm.mybatis.dao;

import com.ssm.mybatis.pojo.StuClass;
import org.apache.ibatis.annotations.Many;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;

public interface IStuClassMapper {
@Select("select * from stu_class where cid= #{cid}")
@Results({ @Result(id = true, column = "cid", property = "cid"),
@Result(column = "cname", property = "cname"),
@Result(column = "sum", property = "sum"),
@Result(column = "cid", property = "stuList",
many = @Many(
select = "com.ssm.mybatis.dao.IStudentMapper.selectStudentByCid"
)
)
})
public StuClass selectStudentByClassId(int id);
}

5.IStudentMapper
package com.ssm.mybatis.dao;

import com.ssm.mybatis.pojo.Student;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

import java.util.List;

public interface IStudentMapper {
@Select("select * from stu_info where sid= #{sid}")
@Results({@Result(id = true, column = "sid", property = "sid"),
@Result(column = "sname", property = "sname"),
@Result(column = "age", property = "age"),
@Result(column = "course", property = "course")})
public Student selectStudentById(int id);

@Update("update stu_info set sname = #{sname}, age = #{age} where sid = #{sid}")
public int updateStudent(Student student);

@Select("select * from stu_info where classid = #{cid}")
public List<Student> selectStudentByCid(int cid);
}

6.StuClass
package com.ssm.mybatis.pojo;

import java.util.List;

public class StuClass {
private int cid;
private String cname;
private int sum;
private List<Student> stuList;

public int getCid() {
return cid;
}

public void setCid(int cid) {
this.cid = cid;
}

public String getCname() {
return cname;
}

public void setCname(String cname) {
this.cname = cname;
}

public int getSum() {
return sum;
}

public void setSum(int sum) {
this.sum = sum;
}

public List<Student> getStuList() {
return stuList;
}

public void setStuList(List<Student> stuList) {
this.stuList = stuList;
}

@Override
public String toString() {
return "StuClass{" +
"cid=" + cid +
", cname='" + cname + '\'' +
", sum=" + sum +
", stuList=" + stuList +
'}';
}
}

7.Student
package com.ssm.mybatis.pojo;

public class Student {
private int sid;
private String sname;
private String age;
private String course;

public int getSid() {
return sid;
}

public void setSid(int sid) {
this.sid = sid;
}

public String getSname() {
return sname;
}

public void setSname(String sname) {
this.sname = sname;
}

public String getAge() {
return age;
}

public void setAge(String age) {
this.age = age;
}

public String getCourse() {
return course;
}

public void setCourse(String course) {
this.course = course;
}

@Override
public String toString() {
return "Student{" +
"sid=" + sid +
", sname='" + sname + '\'' +
", age='" + age + '\'' +
", course='" + course + '\'' +
'}';
}
}

8.MyBatisUtils
package com.ssm.mybatis.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.Reader;

public class MyBatisUtils {
private static SqlSessionFactory sqlSessionFactory = null;
static {
try {
Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
} catch (IOException e) {
e.printStackTrace();
}
}

public static SqlSession getSession()
{
return sqlSessionFactory.openSession();
}
}

9.MyBatisTest
package test;

import com.ssm.mybatis.dao.IStuClassMapper;
import com.ssm.mybatis.dao.IStudentMapper;
import com.ssm.mybatis.pojo.StuClass;
import com.ssm.mybatis.pojo.Student;
import com.ssm.mybatis.utils.MyBatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class MyBatisTest {
@Test
public void findStudentById(){
SqlSession session = MyBatisUtils.getSession();
IStudentMapper iStudentMapper = session.getMapper(IStudentMapper.class);
Student student = iStudentMapper.selectStudentById(1);
System.out.println(student.toString());
session.close();
}

@Test
public void findStudentByCid(){
SqlSession session = MyBatisUtils.getSession();
IStuClassMapper iStuClassMapper = session.getMapper(IStuClassMapper.class);
StuClass stuClass = iStuClassMapper.selectStudentByClassId(1);
List<Student> students = stuClass.getStuList();
for(Student student : students){
System.out.println(student.toString());
}
session.close();
}

@Test
public void updateStudentById(){
SqlSession session = MyBatisUtils.getSession();
IStudentMapper iStudentMapper = session.getMapper(IStudentMapper.class);
Student student = new Student();
student.setSid(1);
student.setSname("lihao");
student.setAge("20");
System.out.println(student);
int cnt = iStudentMapper.updateStudent(student);
if(cnt > 0){
System.out.println("update successful!");
}
session.commit();
session.close();
}
}

 


 


 
 


 


 
 
 

 

       

 

 

标签:String,数据库,javaee,session,org,mybatis,import,public
来源: https://www.cnblogs.com/gxbz/p/16310990.html