Mybatis連線Oracle資料庫一對多
阿新 • • 發佈：2021-01-28
create table clazz( cid number(3) primary key, name varchar2(20) ); create table student( sid number(3) primary key, name varchar2(20), sex char(3), mobile varchar(11), cid number(3) references clazz(cid) ); create sequence clazz_seq; create sequence student_seq; insert into clazz values(clazz_seq.nextval,'魔法班'); insert into clazz values(clazz_seq.nextval,'修仙班'); insert into clazz values(clazz_seq.nextval,'王者班'); insert into student values(student_seq.nextval,'哈利波特','男','13588889800',1)； insert into student values(student_seq.nextval,'泰勒','女','13588889801',1)； insert into student values(student_seq.nextval,'艾薇兒','女','13588889802',1)； insert into student values(student_seq.nextval,'托馬斯','男','13588889803',2)； insert into student values(student_seq.nextval,'雪諾','男','13588889804',2)； insert into student values(student_seq.nextval,'瑟曦','女','13588889805',2)； insert into student values(student_seq.nextval,'唐山','男','13588889806',3)； insert into student values(student_seq.nextval,'火舞','女','13588889807',3)；
package com.baizhi.dao;
import java.util.List;
import com.baizhi.entity.Clazz;
public interface ClazzDao {
List<Clazz> queryAll();
}
<?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.baizhi.dao.ClazzDao"> <!-- 定義resultMap 結果集對映關係--> <resultMap type="Clazz" id="clazzResultMap"> <id column="cid" property="cid"/> <result column="cname" property="name"/> <!-- 封裝關係屬性 此時關係屬性是一個list集合 property 指定關係屬性變數名 ofType執行集合泛型型別的全限定名或別名 --> <collection property="students" ofType="Student"> <id column="sid" property="sid"/> <result column="sname" property="name"/> <result column="sex" property="sex"/> <result column="smobile" property="mobile"/> </collection> </resultMap> <select id="queryAll" resultMap="clazzResultMap"> select c.cid cid,c.name cname, s.sid sid,s.name sname,s.sex sex,s.mobile smobile from clazz c left join student s on c.cid=s.cid </select> </mapper>
package com.baizhi.entity; import java.io.Serializable; import java.util.List; public class Clazz implements Serializable{ private Integer cid; private String name; //指定關係屬性：是一個Student集合 private List<Student> students; public Integer getCid() { return cid; } public void setCid(Integer cid) { this.cid = cid; } public String getName() { return name; } public void setName(String name) { this.name = name; } public List<Student> getStudents() { return students; } public void setStudents(List<Student> students) { this.students = students; } @Override public String toString() { return "Clazz [cid=" + cid + ", name=" + name + ", students=" + students + "]"; } public Clazz(Integer cid, String name, List<Student> students) { super(); this.cid = cid; this.name = name; this.students = students; } public Clazz() { super(); // TODO Auto-generated constructor stub } }
package com.baizhi.entity;
import java.io.Serializable;
import java.util.List;
public class Student implements Serializable{
private Integer sid;
private String name;
private String sex;
private String mobile;
public Integer getSid() {
return sid;
}
public void setSid(Integer sid) {
this.sid = sid;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getMobile() {
return mobile;
}
public void setMobile(String mobile) {
this.mobile = mobile;
}
@Override
public String toString() {
return "Student [sid=" + sid + ", name=" + name + ", sex=" + sex + ", mobile=" + mobile + "]";
}
public Student(Integer sid, String name, String sex, String mobile) {
super();
this.sid = sid;
this.name = name;
this.sex = sex;
this.mobile = mobile;
}
public Student() {
super();
// TODO Auto-generated constructor stub
}
}
package com.baizhi.test;
import java.util.List;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import com.baizhi.dao.ClazzDao;
import com.baizhi.entity.Clazz;
import com.baizhi.entity.Student;
import com.baizhi.util.MybatisUtil;
public class TestClazzDao {
@Test
public void testQueryAll() {
SqlSession sqlSession =MybatisUtil.opSession();
ClazzDao clazzDao =sqlSession.getMapper(ClazzDao.class);
List<Clazz> list = clazzDao.queryAll();
for (Clazz clazz : list) {
System.out.println(clazz.getName()+"班級有：");
List<Student> students =clazz.getStudents();
for (Student student : students) {
System.out.println("\t"+student.getName());
}
}
}
}
package com.baizhi.util;
import java.io.IOException;
import java.io.InputStream;
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.baizhi.dao.AccountDao;
import com.baizhi.entity.Account;
public class MybatisUtil {
public static SqlSessionFactory factory;
//靜態初始程式碼塊，書寫只需要執行一次的操作，靜態程式碼塊的程式碼只在類載入的時候執行一次
static {
InputStream in = null;
try {
//讀取核心配置檔案mybatis-config.xml
in = Resources.getResourceAsStream("mybatis-config.xml");
//建立SqlSessionFactory
factory = new SqlSessionFactoryBuilder().build(in);
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException("初始化工廠失敗");
}finally {
try {
in.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
//建立一個執行緒繫結物件
private static ThreadLocal<SqlSession> tol=new ThreadLocal<SqlSession>();
//返回一個SqlSession
public static SqlSession opSession() {
//先到當前執行緒取一下
SqlSession sqlSession =tol.get();
if(sqlSession==null) {
//建立SqlSession
sqlSession = factory.openSession();
//繫結到當前執行緒
tol.set(sqlSession);
}
return sqlSession;
}
//釋放資源
public static void close(){
SqlSession sqlSession=tol.get();
if(sqlSession!=null) {
sqlSession.close();
tol.remove();//從當前執行緒移除
}
}
//提交事務
public static void commit() {
SqlSession sqlSession=tol.get();
if(sqlSession!=null) {
sqlSession.commit();
}
}
//回滾事務
public static void rollback() {
SqlSession sqlSession=tol.get();
if(sqlSession!=null) {
sqlSession.rollback();
}
}
}
jdbc.propertities:
driver=oracle.jdbc.OracleDriver
url=jdbc:oracle:thin:@localhost:1521:orcl
username=hr
password=hr<?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>
<!-- 引入外部的小配置檔案 -->
<properties resource="jdbc.properties"></properties>
<!-- 給實體類起別名 -->
<typeAliases>
<!-- type屬性值為實體類全限定名
alias 屬性值為別名
-->
<!--<typeAlias type="com.baizhi.entity.Account" alias="Account"/> -->
<!-- 起別名用第二種方式 給實體類起別名 -->
<package name="com.baizhi.entity"/>
</typeAliases>
<!-- 編寫mybatis的執行環境 -->
<environments default="oracle">
<environment id="oracle">
<!-- 指定事務採用JDBC的方式管理 -->
<transactionManager type="JDBC"></transactionManager>
<!-- 使用mybatis提供的POOLED連線池 -->
<dataSource type="POOLED">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${username}"/>
<property name="password" value="${password}"/>
</dataSource>
</environment>
</environments>
<!-- 註冊mapper檔案位置 -->
<mappers>
<!-- 對mapper標籤註冊一個mapper檔案的位置：路徑一定嚴格大小寫 檔案用斜槓，包用點 -->
<mapper resource="com/baizhi/dao/ClazzDaoMapper.xml"></mapper>
</mappers>
</configuration>