方式一、Thumbnailator類庫：size()API方法，
方式二、Java AWT類圖實現：根據縮略比例計算縮略圖高度和寬度，使用Image類獲得原圖的縮放版本，使用ImageIO類保存縮略圖---BufferedImage,ImageIO,Graphips
案例：
springMVC搭建：
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<display-name>Thumbrail</display-name>
<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext-mvc.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>springmvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app><?xml version="1.0" encoding="UTF-8"?>
<beans
xmlns="http://www.springframework.org/schema/beans"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
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/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
">
<mvc:default-servlet-handler/>
<mvc:annotation-driven/>
<context:component-scan base-package="*"/>
<bean id="biewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolve">
<property name="prefix" value="/"/>
<property name="suffix" value=".jsp"/>
<property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
</bean>
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<property name="defaultEncoding" value="utf-8"/>
<property name="maxUploadSize" value="10485760000"/>
<property name="maxInMemorySize" value="40960"/>
</bean>
</beans><%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>上傳文件</title>
</head>
<body>
<div class="demo">
<div class="bheader">
<h2>---圖片文件上傳---</h2>
</div>
<div class="bbody">
<form id="upload_form" enctype="multipart/from-data" method="post" action="${pageContext.request.contextPath}/thumbnail" >
<h2>請選擇上傳圖片</h2>
<div>
<input type="file" name="image" id="image"/>
<input type="submit" value="上傳"/>
</div>
</form>
</div>
</div>
</body>
</html>package com.thumbnail;
import javax.servlet.http.HttpSession;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.commons.CommonsMultipartFile;
import org.springframework.web.portlet.ModelAndView;
@Controller
@RequestMapping("/")
public class ThumbnailAction {
private UploadService u ;
private ThumbnailService t;
//springmvc會將用戶提交的文件信息封裝成爲CommonsMultipartFile文件類型：方法的參數名稱file和文件中提交的文件名稱image是不對應的，需要註解下，讓其統一
@RequestMapping(value="/thumbnail",method=RequestMethod.POST)
public ModelAndView thumbnail(@RequestParam("image")CommonsMultipartFile file,HttpSession session) throws Exception{
String uploadPath = "/images";//縮略圖上傳目錄--相對路徑
String realUploadPath = session.getServletContext().getRealPath(uploadPath);//得到絕對路徑
String imagerUrl = u.uploadImage(file, uploadPath, realUploadPath);;//原圖路徑
String thumImageUrl = t.thumbnail(file, uploadPath, realUploadPath);//縮略圖路徑
ModelAndView ret = new ModelAndView();
ret.addObject("imageURL",imagerUrl);
ret.addObject("thumImageURL",thumImageUrl);
ret.setViewName("thumbnail");
return ret;
}
@Autowired
public void setU(UploadService u) {
this.u = u;
}
@Autowired
public void setT(ThumbnailService t) {
this.t = t;
}
}
package com.thumbnail;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.commons.CommonsMultipartFile;
/**
* 文件上傳實現
* @author Administrator
*
*/
@Service
public class UploadService {
public String uploadImage(CommonsMultipartFile file,String uploadPath,String realUploadPath){
InputStream is = null;
OutputStream out = null;
try {
is = file.getInputStream();//得到文件流
String des = realUploadPath + "/" +file.getOriginalFilename();
out = new FileOutputStream(des);//得到輸出流
byte[] buffer = new byte[1024];
int len = 0;
while((len = is.read(buffer)) > 0){
out.write(buffer);
}
} catch (Exception e) {
// TODO: handle exception
}finally{
if(is != null){
try {
is.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(out != null){
try {
out.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return uploadPath+"/"+file.getOriginalFilename();
}
}
package com.thumbnail;
import net.coobird.thumbnailator.Thumbnails;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.commons.CommonsMultipartFile;
/**
* 縮略圖服務類
* @author Administrator
*
*/
@Service
public class ThumbnailService {
public static final int WIDTH = 100;
public static final int HEIGHT = 100;
public String thumbnail(CommonsMultipartFile file, String uploadPath,String realUploadPath){
try {
String des = realUploadPath + "thum_" + file.getOriginalFilename();
Thumbnails.of(file.getInputStream()).size(WIDTH, HEIGHT).toFile(des);//生成縮略圖
} catch (Exception e) {
// TODO: handle exception
}
return uploadPath + "/thum_" + file.getOriginalFilename();
}
}
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>操作結果</title>
</head>
<body>
<h4>圖片信息</h4>
<hr />
<table width="200">
<tr>
<td width="50%" align="center"><img src="${pageContext.request.contextPath }${imageURL}" width="500"></td>
<td width="50%" align="center"><img src="${pageContext.request.contextPath }${thumbImageURL}" /></td>
</tr>
</table>
<hr/>
<a href="${pageContext.request.contextPath }">返回</a>
</body>
</html>