spring代理例子

Posted 2020-12-04 梁大爷

 

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先来看一下目录结构

 

 

显然service里面有两个java文件，UserDao是接口，UserDaoImpl是接口的实现类，在使用时都是用的接口向外对接

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再来看看所用的jar包

 

 上面的jar基本上是做spring开发的所有jar，但肯定还是不全，需要什么再加什么吧

jar百度网盘链接：https://pan.baidu.com/s/1utLam37cKHNlBaj9z9CSUw

提取码：9eba

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接下来我们看一下核心配置文件

核心配置文件里面很多配置的东西，其实都可以复制，很多都是固定写法

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.0.xsd"
>

<!-- 这里要注意class是实现类，不是接口类-->
<bean id = "userDao" class = "lf.com.service.UserDaoImpl"></bean>

<!-- 建立连接池 -->
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
<property name="url" value="jdbc:mysql://localhost:3306/liuyan"></property>
<property name="username" value="root"></property>
<property name="password" value="1234"></property>
</bean>

<!-- 管理事务的类 -->
<bean id="txManager"
class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource" />
</bean>

<tx:advice id="txadvice" transaction-manager="txManager">
<tx:attributes>
<tx:method name="select*" read-only="true"/>
</tx:attributes>
</tx:advice>

<aop:config>
<aop:pointcut expression="execution(* lf.com.service.UserDao.*(..))" id="mypoint"/>

<!-- 这里也要注意，是pointcut-ref，不是pointcut -->
<aop:advisor advice-ref="txadvice" pointcut-ref="mypoint"/>
</aop:config>

</beans>

 

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接下来是bean类

也就是传说中的封装，其实就是把数据库里的列，封装为一个类的属性，这样通过这个类来使用这些属性

 

package lf.com.bean;

/**
*
* @author Administrator
* 这里User使用的是liuyan这个数据库里面的user表
* 要求属性和表里的列名相同，类型也要相同
*
*/
public class User {
private int id;
private String userName;
private String pwd;
private int age;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPwd() {
return pwd;
}
public void setPwd(String pwd) {
this.pwd = pwd;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public User(int id, String userName, String pwd, int age) {
super();
this.id = id;
this.userName = userName;
this.pwd = pwd;
this.age = age;
}
public User() {
super();
// TODO Auto-generated constructor stub
}
@Override
public String toString() {
return "User [id=" + id + ", userName=" + userName + ", pwd=" + pwd
+ ", age=" + age + "]";
}

}

 

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service中UserDao接口

 

package lf.com.service;

import lf.com.bean.User;

public interface UserDao {
public User select(int id);
}

 

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service中UserDaoImpl实现类

 

package lf.com.service;

import lf.com.bean.User;

public class UserDaoImpl implements UserDao{

@Override
public User select(int id) {
System.out.println("The id is"+ id);
return null;
//throw new UnsupportedOperationException();
}

}

 

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测试类

 

package lf.com.test;

import lf.com.bean.User;
import lf.com.service.UserDao;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Test {

/**
* @param args
*/
public static void main(String[] args) {
System.out.println("before----------");

ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");

System.out.println("after------------");

UserDao userDao = (UserDao)ac.getBean("userDao");

System.out.println("userDado-------------");

User user = userDao.select(3);

if (user != null) {
System.out.print("找到了用户");
}else{
System.out.println("没有找到用户");
}
}

}

 

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结果：

 

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