一、实战：使用@AspectJ注解的例子
下面使用一个简单有趣的例子来演示Spring AOP的用法，演绎一段“武松打虎”的故事情节——武松（Fighter）在山里等着老虎（Tiger）出现，只要发现老虎出来，就打老虎。
1、首先定义老虎Tiger类
package com.spring.Aop;
public class Tiger {
public void walk(){
System.out.println("Tiger is walking");
}
}
2、定义切面和配置
- 定义Fighter类
package com.spring.Aop;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
@Aspect
public class Fighter {
@Pointcut("execution(* com.spring.Aop.Tiger.walk())")
public void foundTiger(){
}
@Before(value="foundTiger()")
public void foundBefore(){
System.out.println("Fighter wait for tiger...");
}
@AfterReturning("foundTiger()")
public void foundAfter(){
System.out.println("Fighter fight with tiger...");
}
}
- 相应的Spring配置：
<?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"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
<!--启动AspectJ支持-->
<aop:aspectj-autoproxy/>
<!--定义bean-->
<bean id="fighter" class="com.spring.Aop.Fighter"/>
<bean id="tiger" class="com.spring.Aop.Tiger"/>
</beans>
- 定义主应用类Application:
package com.spring.Aop;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Applocation {
public static void main(String[] args) {
@SuppressWarnings("rescource")
ApplicationContext context=new ClassPathXmlApplicationContext("spring.xml");
Tiger tiger = context.getBean(Tiger.class);
tiger.walk();
}
}
运行结果：
运行结果
二、图片处理的AOP程序
使用Hutool的工作集
hutool的网址：http://hutool.cn/
对图片进行水印，黑白，裁剪，旋转等
2.1添加图片水印和转换成黑白色
1.业务类，实现图片拷贝
package com.spring.Image;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.*;
/**
* 业务类，实现图片拷贝
*/
public class ImageCopy {
private static final Logger logger = LoggerFactory.getLogger(ImageCopy.class);
public void copyImage()throws IOException{
logger.info("开始将图片从D盘复制到E盘...");
File srcFile = new File("D:/bg.jpg");
File destFile = new File("E:/bg1.jpg");
InputStream in =new FileInputStream(srcFile);
OutputStream out =new FileOutputStream(destFile);
byte[]bytes = new byte[(int) srcFile.length()];
int len;
while((len = in.read(bytes))!= -1){
out.write(bytes,0,len);
}
in.close();
out.close();
}
}
2、图片处理类
package com.spring.Image;
import cn.hutool.core.util.ImageUtil;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* 图片处理类
*/
@Aspect
public class ImageHandler {
private static final Logger logger= LoggerFactory.getLogger(ImageHandler.class);
//切点函数，必须为空
@Pointcut("execution(* com.spring.Image.ImageCopy.copyImage())")
public void handleImage(){
}
@Before(value="handleImage()")
public void pressTextOnImage() throws IOException {
logger.info("开始给图片添加水印");
File srcFile=new File("D:/bg.jpg");
File destFile=new File("D:/bg1.jpg");
// 创建字节输入流一个BufferedImage对象
InputStream input = new FileInputStream(srcFile);
BufferedImage srcImg = ImageIO.read(input);
int width = srcImg.getWidth();
int height = srcImg.getHeight();
System.out.println("原图宽"+width+",y原图高："+height);
Color color = new Color(211,71,38);
int size =60;
Font font = new Font("微软雅黑",Font.BOLD,size);
String text="@微信号：hj";
ImageUtil.pressText(srcFile,destFile,text,color,font,(width-text.length() * size)/2,height/2-size,1.0f);
}
@AfterReturning("handleImage()")
public void grayImage(){
logger.info("开始将图片转成黑白");
File srcFile =new File("E:/bg1.jpg");
File destFile =new File("E:/bg1.jpg");
ImageUtil.gray(srcFile,destFile);
}
}
3、主应用类 ImageCopyApp
package com.spring.Image;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import java.io.IOException;
public class ImageCopyApp {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
ImageCopy imageCopy= context.getBean(ImageCopy.class);
try {
imageCopy.copyImage();
} catch (IOException e) {
e.printStackTrace();
}
}
}
运行结果：
image.png
image.png
这是添加的水印
image.png
这是转成黑白
2.2 生成二维码，简书的主页
package com.spring.Image;
import cn.hutool.core.io.FileUtil;
import cn.hutool.extra.qrcode.QrCodeUtil;
import cn.hutool.extra.qrcode.QrConfig;
import java.awt.*;
public class jianshu {
public static void main(String[] args) {
QrConfig config =new QrConfig(300,300);
config.setMargin(3);
config.setImg("e:/2.png");//二维码的中间logo路径
Color foreColor = new Color(87, 174, 228);
Color bgColor =new Color(255, 250, 227);
int foreColorRGB=foreColor.getRGB();
int bgColorRGB=bgColor.getRGB();
// 设置前景色
config.setForeColor(foreColorRGB);
// 设置背景色
config.setBackColor(bgColorRGB);
// 生成二维码到文件，也可以到流
QrCodeUtil.generate(//
"https://www.jianshu.com/u/997fa4d92222", //二维码内容
config, FileUtil.file("e:/qrcodeWithLogo.jpg")//写出到的文件
);
}
}
运行图片：
二维码
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