jsp在Servlet下载图片和远程加载Servlet上的图片

来源：互联网发布：win10网络设置在哪编辑：程序博客网时间：2024/06/05 15:49

下载图片要使用form，也可以用ajax生成form访问。

到入图片是<img src="ServletPath">实现的

在下载图片时候Servlet要设置：

//一定要设置：attachment表示内容以附件的形式打开
response.setHeader("Content-Disposition","attachment;filename=1.jpg");

加载图片的时候不设置。

jsp

<%@ 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=UTF-8"><title>Insert title here</title><script type="text/javascript">function dlFile(){var oReq = getXMLHttpRequest();oReq.open("POST", "DownLoadFileServlet", true);oReq.setRequestHeader("Content-type","application/x-www-form-urlencoded"); //提交表单必须oReq.send("name=zhangsan&pwd=123");oReq.onreadystatechange = function() {if (oReq.readyState == 4 && oReq.status == 200) {    /*  var res=oReq.responseText; var flag=eval('('+res+')').flag; //json字符串转为json对象document.getElementById("myDiv").innerHTML =flag ; //responseText响应类型是文本 */}}}function getXMLHttpRequest() {var xmlReq;if (window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, SafarixmlReq = new XMLHttpRequest();} else {// code for IE6, IE5xmlReq = new ActiveXObject("Microsoft.XMLHTTP");}return xmlReq;}</script></head><body><form action="DownLoadFileServlet" method="post"><img alt="" src="ViewPhotoServlet" style="width: 100px;height: 100px;"><input type="submit" value="下载图片"/></form></body></html>

下载图片的servlet

package com.file.util;import java.io.FileInputStream;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.ServletOutputStream;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.sun.org.apache.xalan.internal.xsltc.trax.OutputSettings;public class DownLoadFileServlet extends HttpServlet {protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doPost(request, response);}protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {System.out.println("in download");FileInputStream fis=null;ServletOutputStream os=null;try { fis=new FileInputStream("G://temp//b812c8fcc3cec3fdbfd01ad5d688d43f869427a7.jpg");  //一定要设置：attachment表示内容以附件的形式打开 response.setHeader("Content-Disposition","attachment;filename=1.jpg");  os=response.getOutputStream();int len=0;byte[] ns=new byte[1024];while((len=fis.read(ns))>0){os.write(ns, 0, len);;}} catch (Exception e) {e.printStackTrace();}finally{if(os!=null){os.close();}if(fis!=null){fis.close();}}}}

远程加载图片的Servlet

package com.file.util;import java.io.FileInputStream;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.ServletOutputStream;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class ViewPhotoServlet extends HttpServlet {protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doPost(request, response);}protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {System.out.println("in ViewPhotoServlet");FileInputStream fis=null;ServletOutputStream os=null;try { fis=new FileInputStream("G://temp//b812c8fcc3cec3fdbfd01ad5d688d43f869427a7.jpg");   os=response.getOutputStream();int len=0;byte[] ns=new byte[1024];while((len=fis.read(ns))>0){os.write(ns, 0, len);;}} catch (Exception e) {e.printStackTrace();}finally{if(os!=null){os.close();}if(fis!=null){fis.close();}}}}

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