1,建表語句:
create table students(
id int(5) primary key,
name varchar(10),
sal double(8,2)
);
2,javabean:Student.java
/**
* 學生
* @author AdminTC
*/
public class Student {
private Integer id;//編號
private String name;//姓名
private Double sal;//薪水
public Student(){}
public Student(Integer id, String name, Double sal) {
this.id = id;
this.name = name;
this.sal = sal;
}
public Integer getId() {
System.out.println("getId()");
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
System.out.println("getName()");
return name;
}
public void setName(String name) {
this.name = name;
}
public Double getSal() {
System.out.println("getSal()");
return sal;
}
public void setSal(Double sal) {
this.sal = sal;
}
}
3.MybatisUtil.java
/**
* 工具類
* @author AdminTC
*/
public class MybatisUtil {
private static ThreadLocal<SqlSession> threadLocal = new ThreadLocal<SqlSession>();
private static SqlSessionFactory sqlSessionFactory;
/**
* 加載位於src/mybatis.xml配置文件
*/
static{
try {
Reader reader = Resources.getResourceAsReader("mybatis.xml");
sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
} catch (IOException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
/**
* 禁止外界通過new方法創建
*/
private MybatisUtil(){}
/**
* 獲取SqlSession
*/
public static SqlSession getSqlSession(){
//從當前線程中獲取SqlSession對象
SqlSession sqlSession = threadLocal.get();
//如果SqlSession對象爲空
if(sqlSession == null){
//在SqlSessionFactory非空的情況下,獲取SqlSession對象
sqlSession = sqlSessionFactory.openSession();
//將SqlSession對象與當前線程綁定在一起
threadLocal.set(sqlSession);
}
//返回SqlSession對象
return sqlSession;
}
/**
* 關閉SqlSession與當前線程分開
*/
public static void closeSqlSession(){
//從當前線程中獲取SqlSession對象
SqlSession sqlSession = threadLocal.get();
//如果SqlSession對象非空
if(sqlSession != null){
//關閉SqlSession對象
sqlSession.close();
//分開當前線程與SqlSession對象的關係,目的是讓GC儘早回收
threadLocal.remove();
}
}
/**
* 測試
*/
public static void main(String[] args) {
Connection conn = MybatisUtil.getSqlSession().getConnection();
System.out.println(conn!=null?"連接成功":"連接失敗");
}
}
4.Mybatis.xml文件
<?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>
<!-- 加載類路徑下的屬性文件 -->
<properties resource="db.properties"/>
<!-- 設置類型別名 -->
<typeAliases>
<typeAlias type="com.bmw.javaee.mybatis.app04.Student" alias="student"/>
</typeAliases>
<!-- 設置一個默認的連接環境信息 -->
<environments default="mysql_developer">
<!-- 連接環境信息,取一個任意唯一的名字 -->
<environment id="mysql_developer">
<!-- mybatis使用jdbc事務管理方式 -->
<transactionManager type="jdbc"/>
<!-- mybatis使用連接池方式來獲取連接 -->
<dataSource type="pooled">
<!-- 配置與數據庫交互的4個必要屬性 -->
<property name="driver" value="${mysql.driver}"/>
<property name="url" value="${mysql.url}"/>
<property name="username" value="${mysql.username}"/>
<property name="password" value="${mysql.password}"/>
</dataSource>
</environment>
<!-- 連接環境信息,取一個任意唯一的名字 -->
<environment id="oracle_developer">
<!-- mybatis使用jdbc事務管理方式 -->
<transactionManager type="jdbc"/>
<!-- mybatis使用連接池方式來獲取連接 -->
<dataSource type="pooled">
<!-- 配置與數據庫交互的4個必要屬性 -->
<property name="driver" value="${oracle.driver}"/>
<property name="url" value="${oracle.url}"/>
<property name="username" value="${oracle.username}"/>
<property name="password" value="${oracle.password}"/>
</dataSource>
</environment>
</environments>
<!-- 加載映射文件-->
<mappers>
<mapper resource="com/bmw/javaee/mybatis/app04/StudentMapper.xml"/>
</mappers>
</configuration>
5.db.properties
mysql.driver=com.mysql.jdbc.Driver
mysql.url=jdbc:mysql://127.0.0.1:3306/mybatis
mysql.username=root
mysql.password=root
oracle.driver=oracle.jdbc.driver.OracleDriver
oracle.url=jdbc:oracle:thin:@127.0.0.1:1521:orcl
oracle.username=scott
oracle.password=tiger
6.StudentMapper.xml
<?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">
<!-- namespace屬性是名稱空間,必須唯一 -->
<mapper namespace="cn.itcast.javaee.mybatis.app04.Student">
<!-- resultMap標籤:映射實體與表
type屬性:表示實體全路徑名
id屬性:爲實體與表的映射取一個任意的唯一的名字
-->
<resultMap type="student" id="studentMap">
<!-- id標籤:映射主鍵屬性
result標籤:映射非主鍵屬性
property屬性:實體的屬性名
column屬性:表的字段名
-->
<id property="id" column="id"/>
<result property="name" column="name"/>
<result property="sal" column="sal"/>
</resultMap>
<!--
insert標籤:要書寫insert這麼一個sql語句
id屬性:爲insert這麼一個sql語句取一個任意唯一的名字
parameterType:要執行的dao中的方法的參數,如果是類的話,必須使用全路徑類
-->
<insert id="add1">
insert into students(id,name,sal) values(1,'哈哈',7000)
</insert>
<insert id="add2" parameterType="student">
insert into students(id,name,sal) values(#{id},#{name},#{sal})
</insert>
<insert id="add3" parameterType="student">
insert into students(id,name,sal) values(#{id},#{name},#{sal})
</insert>
</mapper>
7.StudentDao.java
/**
* 持久層
* @author AdminTC
*/
public class StudentDao {
/**
* 增加學生
*/
public void add1() throws Exception{
SqlSession sqlSession = null;
try{
sqlSession = MybatisUtil.getSqlSession();
//事務開始(默認)
//讀取StudentMapper.xml映射文件中的SQL語句
int i = sqlSession.insert("cn.itcast.javaee.mybatis.app04.Student.add1");
System.out.println("本次操作影響了"+i+"行");
//事務提交
sqlSession.commit();
}catch(Exception e){
e.printStackTrace();
//事務回滾
sqlSession.rollback();
throw e;
}finally{
MybatisUtil.closeSqlSession();
}
}
/**
* 增加學生
*/
public void add2(Student student) throws Exception{
SqlSession sqlSession = null;
try{
sqlSession = MybatisUtil.getSqlSession();
//事務開始(默認)
//讀取StudentMapper.xml映射文件中的SQL語句
sqlSession.insert(Student.class.getName()+".add2",student);
//事務提交
sqlSession.commit();
}catch(Exception e){
e.printStackTrace();
//事務回滾
sqlSession.rollback();
throw e;
}finally{
MybatisUtil.closeSqlSession();
}
}
/**
* 增加學生
*/
public void add3(Student student) throws Exception{
SqlSession sqlSession = null;
try{
sqlSession = MybatisUtil.getSqlSession();
sqlSession.insert(Student.class.getName()+".add3",student);
sqlSession.commit();
}catch(Exception e){
e.printStackTrace();
sqlSession.rollback();
throw e;
}finally{
MybatisUtil.closeSqlSession();
}
}
public static void main(String[] args) throws Exception{
StudentDao dao = new StudentDao();
dao.add1();
dao.add2(new Student(2,"呵呵",8000D));
dao.add3(new Student(3,"嘻嘻",9000D));
dao.add3(new Student(4,"笨笨",9000D));
}
}