用java socket实现了一个简单的httpserver， 能够处理GET, POST,以及带一个附件的multipart类型的POST。尽管中途遇到了非常多问题， 只是通过在论坛和几个高手交流了一下，问题都攻克了。假设你认为程序有些地方看不明确,能够參看这个帖子:http://topic.csdn.net/u/20090625/22/59a5bfc8-a6b6-445d-9829-ea6d462a4fe6.html.

尽管解析http头不是非常规范，本来应该用原始的字节流， 我採用了一个折衷的方案，用DataInputStream.

本代码的有用性==0，可是能够帮助非常好地了解http协议，然后其它的应用层协议大都如此。

假设你从来都没有了解过http协议，建议先搜索阅读一下，或者你还能够用以下的代码来简单的看一看究竟浏览器和server之间都相互发送了什么数据。

MyHttpClient.java: 模拟浏览器的行为， 向server发送get/post请求，然后打印出server返回的消息。这样就能够查看当一个请求到来之后， server究竟都给浏览器发送了哪些消息。

package socket;

import java.io.*;
import java.net.*;

public class MyHttpClient {
public static void main(String[] args) throws Exception{
InetAddress inet = InetAddress.getByName("www.baidu.com");
System.out.println(inet.getHostAddress());
Socket socket = new Socket(inet.getHostAddress(),80);
InputStream in = socket.getInputStream();
OutputStream out = socket.getOutputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
PrintWriter writer = new PrintWriter(out);
writer.println("GET /home.html HTTP/1.1");//home.html是关于百度的页面
writer.println("Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, application/msword, application/vnd.ms-excel, application/vnd.ms-powerpoint, */*");
writer.println("Accept-Language: en-us,zh-cn;q=0.5");
writer.println("Accept-Encoding: gzip, deflate");
writer.println("Host: www.baidu.com");
writer.println("User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)");
writer.println("Connection: Keep-Alive");
writer.println();
writer.flush();
String line = reader.readLine();
while(line!=null){
System.out.println(line);
line = reader.readLine();
}
reader.close();
writer.close();
}
}

MyServer.java: 模拟server端接收浏览器的请求，然后把整个请求的报文打印出来。程序执行之后直接用浏览器測试。

package socket;

import java.io.*;
import java.net.*;

public class MyServer {
public static void main(String[] args) throws IOException{
ServerSocket svrSocket = new ServerSocket(8080);
while(true){
Socket socket = svrSocket.accept();
//足够大的一个缓冲区
byte[] buf = new byte[1024*1024];
InputStream in = socket.getInputStream();
int byteRead = in.read(buf, 0, 1024*1024);
String dataString = new String(buf, 0, byteRead);
System.out.println(dataString);
in.close();
socket.close();
}
}
}

主程序MyHttpServer.

package socket;

import java.io.*;
import java.net.*;
/**
* MyHttpServer 实现一个简单的HTTPserver端，能够获取用户提交的内容
* 并给用户一个response
* 由于时间的关系，对http头的处理显得不规范
* 对于上传附件，临时仅仅能解析仅仅上传一个附件并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 {
//server根文件夹，post.html, upload.html都放在该位置
public static String WEB_ROOT = "c:/root";
//port
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server根文件夹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();
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......");
/*以下的凝视是一个浏览器发送带附件的请求的全文，全部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"<其它字段或附件>
<这里有一个空行>
<其它字段或附件的内容>
-----------------------------7d925134501f6--<这是multipart分隔符，最后一个分隔符多两个->
****************************************************************/
/**
* 上面的凝视是一个带附件的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) {
//把全部的提交的正文，包含附件和其它字段都先读到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，能够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);
//下面略过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;
//附件開始位置
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;
//下面找出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称路径,比方c:/my file/somedir/project.doc
* 但有时候仅仅显示文件的名字，比方myphoto.jpg.
* 所以须要做一个推断。
*/
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();
}
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，然后依据请求的类别作处理
//在这里我仅仅针对GET和POST作了处理
//当中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();
}
}

測试文件post.html, upload.html都放在上面程序定义的WEB_ROOT以下。

post.html:处理普通的post请求

<html>
<head>
<title>test my server</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<p>upload</p>
来自http://blog.csdn.net/sunxing007<br>
<form name="UploadForm" method="post" action="http://localhost:8080/">
<input type="text" name="myname" /><br>
<select name="myage">
<option value="18">18</option>
<option value="20">20</option>
<option value="22">22</option>
</select><br>
<input type="submit"value="Sutmit">
</form>
</body>
</html>

upload.html:測试带附件的post请求

<head>
<title>my page</title>
<style>
table{
border-collapse: collapse;
}
</style>
</head>
<body>
来自http://blog.csdn.net/sunxing007<br>
<form action='http://localhost:8080/' method='post' enctype='multipart/form-data'>
file: <input type='file' name='myfile' /><br>
<input type='submit' />
</form>
</body>
</html>

一切准备妥当,而且MyHttpServer执行之后, 在浏览器输入http://localhost:8080/post.html和http://localhost:8080/upload.html就可以进行測试.

转载请注明来自http://blog.csdn.net/sunxing007