http协议------费了番脑筋
当我们向服务器提交请求的时候，一般分为post和get，get是将数据通过编码放在url中传输，而且仅仅限定是文本，所以当我们想要解析的时候，只要提取URL在进行字符串的分解就可以实现，但是当我们使用post提交的时候，数据是放在数据区的，接下来我们来看看，什么是数据区
POST / HTTP/1.1 Host: localhost Connection: keep-alive Content-Length: 339 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8 Origin: file:// User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/30.0.1599.101 Safari/537.36 Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryXRRcAQBkcqSNCep4 Accept-Encoding: gzip,deflate,sdch Accept-Language: zh-CN,zh;q=0.8
<span style="background-color: rgb(204, 204, 204);">Content-Disposition: form-data; name="music"; filename="1.txt" Content-Type: text/plain 11111111111 ------WebKitFormBoundaryXRRcAQBkcqSNCep4 Content-Disposition: form-data; name="file"; filename="2.txt" Content-Type: text/plain 2222222222222</span> <span style="background-color: rgb(192, 192, 192);">------WebKitFormBoundaryXRRcAQBkcqSNCep4--</span> oundary=----WebKitFormBoundaryXRRcAQBkcqSNCep4 Accept-Encoding: gzip,deflate,sdch Accept-Language: zh-CN,zh;q=0.8这是我上传文件的一个实例程序的结果，着重注意的是加灰色的地方，其实也可以理解为键值对
再来看看我们的html：
<form action='http://localhost:80/' method='post' enctype='multipart/form-data'>
<span style="white-space:pre"> </span>file: <input type='file' name='music' /><br>
<span style="white-space:pre"> </span>file: <input type='file' name='file' /><br>
<span style="white-space:pre"> </span><input type='submit' />
</form> 这个会使浏览器发送数据，如果不加，浏览器则当其位一个普通的form表单
ming=%B5%DA%D2%BB%B8%F6input%B2%CE%CA%FD&wenjian=1.txt&submit=%CC%E1%BD%BB不会把他当作一个带附件的表单给上传
最后附上一段迷你的http服务器的小例子：
package socket;
import java.io.*;
import java.net.*;
/**
* MyHttpServer 实现一个简单的HTTP服务器端，可以获取用户提交的内容 并给用户一个response
* 因为时间的关系，对http头的处理显得不规范 对于上传附件，暂时只能解析只上传一个附件而且附件位置在第一个的情况
* 转载请注明来自http://blog.csdn.net/sunxing007
* **/
public class MyHttpServer {
// 服务器根目录，post.html, upload.html都放在该位置
public static String WEB_ROOT = "c:/root";
// 端口
private int port;
// 用户请求的文件的url
private String requestPath;
// mltipart/form-data方式提交post的分隔符,
private String boundary = null;
// post提交请求的正文的长度
private int contentLength = 0;
public MyHttpServer(String root, int port) {
WEB_ROOT = root;
this.port = port;
requestPath = null;
}
// 处理GET请求
private void doGet(DataInputStream reader, OutputStream out)
throws Exception {
if (new File(WEB_ROOT + this.requestPath).exists()) {
// 从服务器根目录下找到用户请求的文件并发送回浏览器
InputStream fileIn = new FileInputStream(WEB_ROOT
+ this.requestPath);
byte[] buf = new byte[fileIn.available()];
fileIn.read(buf);
out.write(buf);
out.close();
fileIn.close();
reader.close();
System.out.println("request complete.");
}
}
// 处理post请求
private void doPost(DataInputStream reader, OutputStream out)
throws Exception {
String line = reader.readLine();
while (line != null) {
System.out.println(line);
line = reader.readLine();
System.out.println(line);
if ("".equals(line)) {
break;
} else if (line.indexOf("Content-Length") != -1) {
this.contentLength = Integer.parseInt(line.substring(line
.indexOf("Content-Length") + 16));
}
// 表明要上传附件， 跳转到doMultiPart方法。
else if (line.indexOf("multipart/form-data") != -1) {
// 得multiltipart的分隔符
this.boundary = line.substring(line.indexOf("boundary") + 9);
this.doMultiPart(reader, out);
return;
}
}
// 继续读取普通post（没有附件）提交的数据
System.out.println("begin reading posted data......");
String dataLine = null;
// 用户发送的post数据正文
byte[] buf = {};
int size = 0;
if (this.contentLength != 0) {
buf = new byte[this.contentLength];
while (size < this.contentLength) {
int c = reader.read();
buf[size++] = (byte) c;
}
System.out.println("The data user posted: "
+ new String(buf, 0, size));
}
// 发送回浏览器的内容
String response = "";
response += "HTTP/1.1 200 OK\n";
response += "Server: Sunpache 1.0\n";
response += "Content-Type: text/html\n";
response += "Last-Modified: Mon, 11 Jan 1998 13:23:42 GMT\n";
response += "Accept-ranges: bytes";
response += "\n";
String body = "<html><head><title>test server</title></head><body><p>post ok:</p>"
+ new String(buf, 0, size) + "</body></html>";
System.out.println(body);
out.write(response.getBytes());
out.write(body.getBytes());
out.flush();
reader.close();
out.close();
System.out.println("request complete.");
}
// 处理附件
private void doMultiPart(DataInputStream reader, OutputStream out)
throws Exception {
System.out.println("doMultiPart ......");
String line = reader.readLine();
while (line != null) {
System.out.println(line);
line = reader.readLine();
if ("".equals(line)) {
break;
} else if (line.indexOf("Content-Length") != -1) {
this.contentLength = Integer.parseInt(line.substring(line
.indexOf("Content-Length") + 16));
System.out.println("contentLength: " + this.contentLength);
} else if (line.indexOf("boundary") != -1) {
// 获取multipart分隔符
this.boundary = line.substring(line.indexOf("boundary") + 9);
}
}
System.out.println("begin get data......");
/*
* 下面的注释是一个浏览器发送带附件的请求的全文，所有中文都是说明性的文字***** <HTTP头部内容略> ............
* Cache-Control: no-cache <这里有一个空行，表明接下来的内容都是要提交的正文>
* -----------------------------7d925134501f6<这是multipart分隔符>
* Content-Disposition: form-data; name="myfile"; filename="mywork.doc"
* Content-Type: text/plain
*
* <附件正文>........................................
* .................................................
*
* -----------------------------7d925134501f6<这是multipart分隔符>
* Content-Disposition: form-data; name="myname"<其他字段或附件> <这里有一个空行>
* <其他字段或附件的内容>
* -----------------------------7d925134501f6--<这是multipart分隔符
* ，最后一个分隔符多两个->
* **************************************************************
*/
/**
* 上面的注释是一个带附件的multipart类型的POST的全文模型， 要把附件去出来，就是要找到附件正文的起始位置和结束位置
* **/
if (this.contentLength != 0) {
// 把所有的提交的正文，包括附件和其他字段都先读到buf.
byte[] buf = new byte[this.contentLength];
int totalRead = 0;
int size = 0;
while (totalRead < this.contentLength) {
size = reader.read(buf, totalRead, this.contentLength
- totalRead);
totalRead += size;
}
// 用buf构造一个字符串，可以用字符串方便的计算出附件所在的位置
String dataString = new String(buf, 0, totalRead);
System.out.println("the data user posted:\n" + dataString);
int pos = dataString.indexOf(boundary);
// 以下略过4行就是第一个附件的位置
pos = dataString.indexOf("\n", pos) + 1;
pos = dataString.indexOf("\n", pos) + 1;
pos = dataString.indexOf("\n", pos) + 1;
pos = dataString.indexOf("\n", pos) + 1;
// 附件开始位置
int start = dataString.substring(0, pos).getBytes().length;
pos = dataString.indexOf(boundary, pos) - 4;
// 附件结束位置
int end = dataString.substring(0, pos).getBytes().length;
// 以下找出filename
int fileNameBegin = dataString.indexOf("filename") + 10;
int fileNameEnd = dataString.indexOf("\n", fileNameBegin);
String fileName = dataString.substring(fileNameBegin, fileNameEnd);
/**
* 有时候上传的文件显示完整的文件名路径,比如c:\my file\somedir\project.doc
* 但有时候只显示文件的名字，比如myphoto.jpg. 所以需要做一个判断。
*/
if (fileName.lastIndexOf("\\") != -1) {
fileName = fileName.substring(fileName.lastIndexOf("\\") + 1);
}
fileName = fileName.substring(0, fileName.length() - 2);
OutputStream fileOut = new FileOutputStream("c:\\" + fileName);
fileOut.write(buf, start, end - start);
fileOut.close();
fileOut.close();
fileOut.close();
}
String response = "";
response += "HTTP/1.1 200 OK\n";
response += "Server: Sunpache 1.0\n";
response += "Content-Type: text/html\n";
response += "Last-Modified: Mon, 11 Jan 1998 13:23:42 GMT\n";
response += "Accept-ranges: bytes";
response += "\n";
out.write("<html><head><title>test server</title></head><body><p>Post is ok</p></body></html>"
.getBytes());
out.flush();
reader.close();
System.out.println("request complete.");
}
public void service() throws Exception {
ServerSocket serverSocket = new ServerSocket(this.port);
System.out.println("server is ok.");
// 开启serverSocket等待用户请求到来，然后根据请求的类别作处理
// 在这里我只针对GET和POST作了处理
// 其中POST具有解析单个附件的能力
while (true) {
Socket socket = serverSocket.accept();
System.out.println("new request coming.");
DataInputStream reader = new DataInputStream(
(socket.getInputStream()));
String line = reader.readLine();
String method = line.substring(0, 4).trim();
OutputStream out = socket.getOutputStream();
this.requestPath = line.split(" ")[1];
System.out.println(method);
if ("GET".equalsIgnoreCase(method)) {
System.out.println("do get......");
this.doGet(reader, out);
} else if ("POST".equalsIgnoreCase(method)) {
System.out.println("do post......");
this.doPost(reader, out);
}
socket.close();
System.out.println("socket closed.");
}
}
public static void main(String args[]) throws Exception {
MyHttpServer server = new MyHttpServer("c:/root", 8080);
server.service();
}
}