通过Google和Flickr图片源获取图片并以多线程方式保存图片
这是一个WebProject
首先是web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <servlet> <servlet-name>GetImageServlet</servlet-name> <servlet-class>com.jadyer.servlet.GetImageServlet</servlet-class> </servlet> <servlet> <servlet-name>SaveImageServlet</servlet-name> <servlet-class>com.jadyer.servlet.SaveImageServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>GetImageServlet</servlet-name> <url-pattern>/servlet/GetImageServlet</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>SaveImageServlet</servlet-name> <url-pattern>/servlet/SaveImageServlet</url-pattern> </servlet-mapping> </web-app>
其次是index.jsp
<%@ page language="java" pageEncoding="UTF-8"%>
<script type="text/javascript" src="scripts/jquery-1.7.1.js"></script>
<script type="text/javascript">
$(function(){
$('#buttonQuery').click(function(){
$.get('servlet/GetImageServlet',
{
categoryName: $('#categoryName').val(), //获取文本框中的值，即所要查询的关键字
picSource: $('input[name=picSource]:checked').val() //获取所选择的图片数据源的值
},
function(returnedData, status){
$('#picDiv').empty(); //清空这个<div>中的内容
var html = '';
for(var i=0; i<returnedData.length; i++){
html += "<img src='" + returnedData[i] + "' style='width:200px; height:200px;'/>";
}
$('#picDiv').append(html);
}
);
});
$('#buttonSave').click(function(){
$('#saveStatus').html("<font color='red'><b>Save Processing</b></font>");
$.post('servlet/SaveImageServlet',
function(result){
$('#saveStatus').html("<font color='blue'><b>" + result + "</b></font>");
}
);
});
})
</script>
<input type="text" id="categoryName"/>
<input type="radio" name="picSource" value="google" checked="checked">Google
<input type="radio" name="picSource" value="flickr">Flickr
<input type="button" value="query" id="buttonQuery">
<input type="button" value="save" id="buttonSave">
<div id="saveStatus"></div>
<div id="picDiv"></div>
然后是专门处理网络连接的工具类NetworkUtil.java
package com.jadyer.util;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.net.URL;
/**
* 专门处理网络连接的工具类
* @author 宏宇
* @editor Feb 9, 2012 11:51:14 AM
*/
public class NetworkUtil {
/**
* 根据指定的URL获取其返回的内容
*/
public static String getStringContentFromURL(String url){
StringBuffer sb = new StringBuffer();
InputStream is = null;
InputStreamReader isr = null;
BufferedReader br = null;
try{
is = new URL(url).openConnection().getInputStream();
isr = new InputStreamReader(is, "UTF-8");
br = new BufferedReader(isr);
String line = null;
while(null != (line=br.readLine())){
sb.append(line);
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}finally{
if(null != br){
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(null != isr){
try {
isr.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(null != is){
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return sb.toString();
}
/**
* 完成文件的写入操作
*/
public static void writeToLocalFromInternet(String imageUrl, File file){
InputStream is = null; //定义在外面，是因为我们要在finally{}中将其关掉
OutputStream os = null;
try{
is = new URL(imageUrl).openStream();
os = new FileOutputStream(file);
int length = -1;
byte[] buffer = new byte[7092];
while(-1 != (length=is.read(buffer,0,7092))){
os.write(buffer, 0, length);
}
}catch (IOException e) {
e.printStackTrace();
}finally{
if(null != is){
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(null != os){
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
然后是处理图片保存操作的线程类SaveImageThread.java
package com.jadyer.util;
import java.io.File;
/**
* 处理图片保存操作的线程类
* @see 也可通过extends Thread类的方式，编写线程类，但人们更多的喜欢implements Runnable接口
* @see 其实二者的效率，不见得就要差很多，可能implements Runnable更接近于面向对象的编程思想吧
* @author 宏宇
* @create Feb 11, 2012 12:38:08 AM
*/
public class SaveImageThread implements Runnable {
private File directory;
private String[] imageUrls;
public SaveImageThread(File directory, String[] imageUrls){
this.directory = directory;
this.imageUrls = imageUrls;
}
public void run() {
long startTime = System.currentTimeMillis();
for(String imageUrl : imageUrls){
int position = imageUrl.lastIndexOf("/");
String imageName = imageUrl.substring(position + 1);
File file = new File(directory, imageName);
NetworkUtil.writeToLocalFromInternet(imageUrl, file);
}
long endTime = System.currentTimeMillis();
System.out.println("线程" + Thread.currentThread().getName() + "保存图片,使用时间:" + (endTime-startTime) + "ms");
}
}
下面是用于获取图片的GetImageServlet.java
package com.jadyer.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import com.jadyer.util.NetworkUtil;
/**
* 获取图片的Servlet
* @author 宏宇
* @editor Feb 9, 2012 2:27:58 AM
*/
public class GetImageServlet extends HttpServlet {
private static final long serialVersionUID = -589346586269837420L;
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String categoryName = request.getParameter("categoryName");
String picSource = request.getParameter("picSource");
List<String> urlResult = new ArrayList<String>();
String googleURL = "https://ajax.googleapis.com/ajax/services/search/images?rsz=large&v=1.0&";
String flickrURL = "http://api.flickr.com/services/rest/?method=flickr.photos.search&api_key=da8e8c6840579831969d1a87d37ae545&per_page=150&format=json&extras=original_format&tags=";
if("google".equals(picSource)){
urlResult = this.getGoogleImage(googleURL, categoryName);
}else{
urlResult = this.getFlickrImage(flickrURL, categoryName);
}
JSONArray jsonResult = JSONArray.fromObject(urlResult);
response.setContentType("application/json; charset=UTF-8");
response.setHeader("pragma", "no-cache");
response.setHeader("cache-control", "no-cache");
PrintWriter out = response.getWriter();
out.print(jsonResult);
out.flush();
out.close();
//将相关信息保存到session中，以便在保存图片时使用
HttpSession session = request.getSession();
session.setAttribute("categoryName", categoryName);
session.setAttribute("picSource", picSource);
session.setAttribute("images", urlResult);
}
/**
* Google图片或获取源
* @param googleURL Google图片服务器的URL
* @param categoryName 所要查询的图片关键字
* @return 包含了所有查询出来的图片URL的一个List
*/
private List<String> getGoogleImage(String googleURL, String categoryName){
//存储向客户端发送的url列表。对于Google来说，每次是64个URL。对于Flickr来说，可以设定每次返回多少个URL
List<String> returnedList = new ArrayList<String>();
//存储每次循环时，从Google所获取的json数据。对于Flickr来说则不需要这样，因为Flickr一次就能获得所有的图片
List<String> jsonList = new ArrayList<String>();
//每次取4*8张图片
for(int i=0; i<4; i++){
String url = new StringBuffer(googleURL).append("q=").append(categoryName).append("&start=").append(8*i).toString();
jsonList.add(NetworkUtil.getStringContentFromURL(url));
}
for(String result : jsonList){
JSONObject jsonStr = JSONObject.fromObject(result);
JSONObject responseData = jsonStr.getJSONObject("responseData");
JSONArray results = responseData.getJSONArray("results");
for(int i=0; i<results.size(); i++){
JSONObject jsonObject = results.getJSONObject(i);
returnedList.add(jsonObject.getString("url")); //得到图片的URL，并放到returnedList中
}
}
return returnedList;
}
/**
* Flickr图片获取源
* @param flickrURL Flickr图片服务器的URL
* @param categoryName 所要查询的图片关键字
* @return 包含了所有查询出来的图片URL的一个List
*/
private List<String> getFlickrImage(String flickrURL, String categoryName){
List<String> returnedList = new ArrayList<String>();
String jsonContent = NetworkUtil.getStringContentFromURL(flickrURL + categoryName);
//将Flickr返回的json字符串中，开始部分的'jsonFlickrApi('和结尾部分的')'截掉，剩下的就是一个标准的json格式的字符串了
jsonContent = jsonContent.substring(14, jsonContent.length()-1);
JSONObject jsonObject = JSONObject.fromObject(jsonContent);
//先获取到photos对应的对象，然后再获取到photo对应的数组
JSONArray jsonArray = jsonObject.getJSONObject("photos").getJSONArray("photo");
for(int i=0; i<jsonArray.size(); i++){
JSONObject object = jsonArray.getJSONObject(i);
String ID = object.getString("id");
String secretID = object.getString("secret");
String serverID = object.getString("server");
int farmID = object.getInt("farm"); //Flickr返回的farm值是一个整型数字
//拼接http://farm{farm-id}.staticflickr.com/{server-id}/{id}_{secret}.jpg
StringBuffer sb = new StringBuffer();
sb.append("http://farm").append(farmID).append(".staticflickr.com/").append(serverID).append("/").append(ID).append("_").append(secretID).append(".jpg");
returnedList.add(sb.toString());
}
return returnedList;
}
}
最后是采用多线程方式保存图片的SaveImageServlet.java
package com.jadyer.servlet;
import java.io.File;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import com.jadyer.util.SaveImageThread;
/**
* 采用多线程的方式保存图片的Servlet
* @author 宏宇
* @create Feb 10, 2012 1:33:37 AM
*/
public class SaveImageServlet extends HttpServlet {
private static final long serialVersionUID = 5268619679635561228L;
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//得到在获取图片时，保存到session中的内容
HttpSession session = request.getSession();
String categoryName = (String)session.getAttribute("categoryName");
String picSource = (String)session.getAttribute("picSource");
List<String> list = (List<String>)session.getAttribute("images");
//获取到WebRoot下面的storeImages文件夹的绝对路径，得到的这个path就表示storeImages文件夹在服务器端硬盘上的绝对路径
String path = request.getSession().getServletContext().getRealPath("/storeImages");
//根据查询的图片的关键字以及图片源构造子目录
File directory = new File(path, picSource + "/" + categoryName);
//将所有的目录，包括子目录，一并创建好
directory.mkdirs();
// /**
// * 单线程
// */
// long startTime = System.currentTimeMillis();
// for(String imageUrl : list){
// //获取一个图片URL中的，图片名前面的"/"的位置
// int postion = imageUrl.lastIndexOf("/");
// //name of the image
// String imageName = imageUrl.substring(postion+1);
// //构造一个包含目录和图片名的File对象，接下来再以输出流的形式写到硬盘上
// File file = new File(directory, imageName);
// NetworkUtil.writeToLocalFromInternet(imageUrl, file);
// }
// System.out.println("单线程保存图片,合计使用时间:" + (System.currentTimeMillis()-startTime) + "ms");
// /**
// * 多线程：每个线程处理1张图片
// */
// String[] array2 = null;
// for(int i=0; i<list.size(); i++){
// array = new String[1];
// String imageUrl = list.get(i);
// array[0] = imageUrl;
// new Thread(new SaveImageThread(directory, array)).start();
// }
/**
* 多线程：每个线程处理4张图片
*/
String[] array = null;
for(int i=0; i<list.size(); i++){
String imageUrl = list.get(i);
//array[0]：0、4、8 、12
//array[1]：1、5、9 、13
//array[2]：2、6、10、14
//array[3]：3、7、11、15
//每个线程处理一个array数组中的四个元素
if(i%4 == 0){
if(0 != i){
new Thread(new SaveImageThread(directory, array)).start();
}
array = new String[4];
}
array[i%4] = imageUrl;
}
response.setContentType("text/html");
response.getWriter().print("Save Success");
response.getWriter().flush();
response.getWriter().close();
}
}
补充：在GetImageServlet.java中，用到了Json-lib-2.4的相关jar。大家可以Email给我，我发给你们
也可以直接在我的另一篇博文中找到下载方法，其访问地址为：使用Json-lib生成JSON文本