我用Java 编写了一个HTTP下载的程序,通过Socket建立链接,发送请求和接收文件。现在在接收文件的时候出现了问题,接收的数据中包含了HTTP响应信息,即:
HTTP/1.1 200 OK
Date: Sun, 02 Aug 2009 08:49:22 GMT
Server: Apache/2.2.11 (Unix) mod_ssl/2.2.11 OpenSSL/0.9.8k DAV/2 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635
Last-Modified: Thu, 04 Jun 2009 15:36:14 GMT
ETag: "78878f-49e-46b87893bd780"
Accept-Ranges: bytes
Content-Length: 1182
Connection: close
Content-Type: text/plain
我想把这段过滤掉,因为这不是文件本身应有的数据,各位有什么好的方法吗?
我试过的方法:附加的代码中方法download()。把读取的字节流转成字符串,判断两个“回车换行”的位置,取子字符串再转成字节保存。虽然这方法能把把这段响应信息过滤掉,但是打开文件显示已损坏,我想应该是转为字符串时编码出了问题,导致再转回字节时出了问题。
附上我的源代码,请各位给个思路
package net;import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.util.Arrays;
import java.util.List;public class HTTPDownload {
/** * 过滤响应字符串; */ public static void download() throws IOException{ //建立Socket链接 Socket socket = new Socket("www.chentaoqian.com",80); //构造请求字符串 StringBuffer sb = new StringBuffer(); sb.append("GET ").append("/test.rar ").append("HTTP/1.1\r\n"); sb.append("Host:www.chentaoqian.com\r\n"); sb.append("Accept:*/*\r\n"); sb.append("User-Agent:GeneralDownloadApplication\r\n"); sb.append("Connection:close\r\n\r\n");
// System.out.println("send command.");
//发送请求
OutputStream socketOut = socket.getOutputStream();
socketOut.write(sb.toString().getBytes());
socket.shutdownOutput();// System.out.println("start receive.");
//开始接收数据
InputStream socketIn = socket.getInputStream();
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
byte[] buff = new byte[1024];
int len = -1;
boolean flag = false; //标识是否已完成响应信息过滤;true-完成,false-未完成
String temp = "";
while((len=socketIn.read(buff))!=-1){
if(flag == false){
//过滤响应信息;
//因为响应信息出现在响应流的一开始并且以两个回车换行结束("\r\n\r\n"),所以以此做判断;
temp += new String(buff);
if(temp.indexOf("\r\n\r\n") != -1){
// buff = temp.substring(temp.indexOf("\r\n\r\n")+4).getBytes();
// len = buff.length;
buffer.write(buff, temp.indexOf("\r\n\r\n"), temp.substring(temp.indexOf("\r\n\r\n")+4).getBytes().length);
flag = true;
}continue; }else{ buffer.write(buff,0,len); } } System.out.println(buffer.toString()); //将数据写入文件保存; File f = new File("./aaaa.rar"); FileOutputStream fos = new FileOutputStream(f); buffer.writeTo(fos); fos.close(); socketIn.close(); socketOut.close(); socket.close(); System.out.println("文件保存到:"+f.getAbsolutePath()); } /** * 没有过滤响应字符串; */ public static void download2() throws IOException{ //建立Socket链接 Socket socket = new Socket("www.chentaoqian.com",80); //构造请求字符串 StringBuffer sb = new StringBuffer(); sb.append("GET ").append("/test.rar ").append("HTTP/1.1\r\n"); sb.append("Host:www.chentaoqian.com\r\n"); sb.append("Accept:*/*\r\n"); sb.append("User-Agent:GeneralDownloadApplication\r\n"); sb.append("Connection:close\r\n\r\n");
// System.out.println("send command.");
//发送请求
OutputStream socketOut = socket.getOutputStream();
socketOut.write(sb.toString().getBytes());
socket.shutdownOutput();// System.out.println("start receive.");
//开始接收数据
InputStream socketIn = socket.getInputStream();
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
byte[] buff = new byte[1024];
int len = -1;
while((len=socketIn.read(buff))!=-1){
buffer.write(buff,0,len);
}// System.out.println(buffer.toString());
//将数据写入文件保存;
File f = new File("./aaaa2.rar");
FileOutputStream fos = new FileOutputStream(f);
buffer.writeTo(fos);
fos.close();
socketIn.close();
socketOut.close();
socket.close();
System.out.println("文件保存到:"+f.getAbsolutePath());
}/** * @param args */ public static void main(String[] args) throws Exception { HTTPDownload.download();
// HTTPDownload.download2();
}
}
问题补充
那要怎么做比较好,我是因为看到关于socket发送HTTP请求的文章才想到用socket读取数据。
beckrabbit可以给个思路吗?