如何开发自己的HttpServer-NanoHttpd源码解读
2016-06-14 10:42
375 查看
现在作为一个开发人员，http server相关的内容已经是无论如何都要了解的知识了。用curl发一个请求，配置一下apache，部署一个web server对我们来说都不是很难，但要想搞清楚这些背后都发生了什么技术细节还真不是很简单的。所以新的系列将是分享我学习Http Server的过程。
NanoHttpd是Github上的一个开源项目，号称只用一个java文件就能创建一个http server，我将通过分析NanoHttpd的源码解析如何开发自己的HttpServer。Github 地址：https://github.com/NanoHttpd/nanohttpd
在开始前首先简单说明HttpServer的基本要素：
1.能接受HttpRequest并返回HttpResponse
2.满足一个Server的基本特征，能够长时间运行
关于Http协议一般HttpServer都会声明支持Http协议的哪些特性，nanohttpd作为一个轻量级的httpserver只实现了最简单、最常用的功能，不过我们依然可以从中学习很多。
首先看下NanoHttpd类的start函数
[java]
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copy
public void start() throws IOException {
myServerSocket = new ServerSocket();
myServerSocket.bind((hostname != null) ? new InetSocketAddress(hostname, myPort) : new InetSocketAddress(myPort));
myThread = new Thread(new Runnable() {
@Override
public void run() {
do {
try {
final Socket finalAccept = myServerSocket.accept();
registerConnection(finalAccept);
finalAccept.setSoTimeout(SOCKET_READ_TIMEOUT);
final InputStream inputStream = finalAccept.getInputStream();
asyncRunner.exec(new Runnable() {
@Override
public void run() {
OutputStream outputStream = null;
try {
outputStream = finalAccept.getOutputStream();
TempFileManager tempFileManager = tempFileManagerFactory.create();
HTTPSession session = new HTTPSession(tempFileManager, inputStream, outputStream, finalAccept.getInetAddress());
while (!finalAccept.isClosed()) {
session.execute();
}
} catch (Exception e) {
// When the socket is closed by the client, we throw our own SocketException
// to break the "keep alive" loop above.
if (!(e instanceof SocketException && "NanoHttpd Shutdown".equals(e.getMessage()))) {
e.printStackTrace();
}
} finally {
safeClose(outputStream);
safeClose(inputStream);
safeClose(finalAccept);
unRegisterConnection(finalAccept);
}
}
});
} catch (IOException e) {
}
} while (!myServerSocket.isClosed());
}
});
myThread.setDaemon(true);
myThread.setName("NanoHttpd Main Listener");
myThread.start();
}
1.创建ServerSocket，bind制定端口
2.创建主线程，主线程负责和client建立连接
3.建立连接后会生成一个runnable对象放入asyncRunner中，asyncRunner.exec会创建一个线程来处理新生成的连接。
4.新线程首先创建了一个HttpSession，然后while(true)的执行httpSession.exec。
这里介绍下HttpSession的概念，HttpSession是java里Session概念的实现，简单来说一个Session就是一次httpClient->httpServer的连接，当连接close后session就结束了，如果没结束则session会一直存在。这点从这里的代码也能看到：如果socket不close或者exec没有抛出异常（异常有可能是client段断开连接）session会一直执行exec方法。
一个HttpSession中存储了一次网络连接中server应该保存的信息，比如：URI，METHOD，PARAMS，HEADERS，COOKIES等。
5.这里accept一个client的socket就创建一个独立线程的server模型是ThreadServer模型，特点是一个connection就会创建一个thread，是比较简单、常见的socket server实现。缺点是在同时处理大量连接时线程切换需要消耗大量的资源，如果有兴趣可以了解更加高效的NIO实现方式。
当获得client的socket后自然要开始处理client发送的httprequest。
Http Request Header的parse：
[plain]
view plain
copy
// Read the first 8192 bytes.
// The full header should fit in here.
// Apache's default header limit is 8KB.
// Do NOT assume that a single read will get the entire header at once!
byte[] buf = new byte[BUFSIZE];
splitbyte = 0;
rlen = 0;
{
int read = -1;
try {
read = inputStream.read(buf, 0, BUFSIZE);
} catch (Exception e) {
safeClose(inputStream);
safeClose(outputStream);
throw new SocketException("NanoHttpd Shutdown");
}
if (read == -1) {
// socket was been closed
safeClose(inputStream);
safeClose(outputStream);
throw new SocketException("NanoHttpd Shutdown");
}
while (read > 0) {
rlen += read;
splitbyte = findHeaderEnd(buf, rlen);
if (splitbyte > 0)
break;
read = inputStream.read(buf, rlen, BUFSIZE - rlen);
}
}
1.读取socket数据流的前8192个字节，因为http协议中头部最长为8192
2.通过findHeaderEnd函数找到header数据的截止位置，并把位置保存到splitbyte内。
[java]
view plain
copy
if (splitbyte < rlen) {
inputStream.unread(buf, splitbyte, rlen - splitbyte);
}
parms = new HashMap<String, String>();
if(null == headers) {
headers = new HashMap<String, String>();
}
// Create a BufferedReader for parsing the header.
BufferedReader hin = new BufferedReader(new InputStreamReader(new ByteArrayInputStream(buf, 0, rlen)));
// Decode the header into parms and header java properties
Map<String, String> pre = new HashMap<String, String>();
decodeHeader(hin, pre, parms, headers);
1.使用unread函数将之前读出来的body pushback回去，这里使用了pushbackstream，用法比较巧妙，因为一旦读到了header的尾部就需要进入下面的逻辑来判断是否需要再读下去了，而不应该一直读，读到没有数据为止
2.decodeHeader，将byte的header转换为java对象
[java]
view plain
copy
private int findHeaderEnd(final byte[] buf, int rlen) {
int splitbyte = 0;
while (splitbyte + 3 < rlen) {
if (buf[splitbyte] == '\r' && buf[splitbyte + 1] == '\n' && buf[splitbyte + 2] == '\r' && buf[splitbyte + 3] == '\n') {
return splitbyte + 4;
}
splitbyte++;
}
return 0;
}
1.http协议规定header和body之间使用两个回车换行分割
[java]
view plain
copy
private void decodeHeader(BufferedReader in, Map<String, String> pre, Map<String, String> parms, Map<String, String> headers)
throws ResponseException {
try {
// Read the request line
String inLine = in.readLine();
if (inLine == null) {
return;
}
StringTokenizer st = new StringTokenizer(inLine);
if (!st.hasMoreTokens()) {
throw new ResponseException(Response.Status.BAD_REQUEST, "BAD REQUEST: Syntax error. Usage: GET /example/file.html");
}
pre.put("method", st.nextToken());
if (!st.hasMoreTokens()) {
throw new ResponseException(Response.Status.BAD_REQUEST, "BAD REQUEST: Missing URI. Usage: GET /example/file.html");
}
String uri = st.nextToken();
// Decode parameters from the URI
int qmi = uri.indexOf('?');
if (qmi >= 0) {
decodeParms(uri.substring(qmi + 1), parms);
uri = decodePercent(uri.substring(0, qmi));
} else {
uri = decodePercent(uri);
}
// If there's another token, it's protocol version,
// followed by HTTP headers. Ignore version but parse headers.
// NOTE: this now forces header names lowercase since they are
// case insensitive and vary by client.
if (st.hasMoreTokens()) {
String line = in.readLine();
while (line != null && line.trim().length() > 0) {
int p = line.indexOf(':');
if (p >= 0)
headers.put(line.substring(0, p).trim().toLowerCase(Locale.US), line.substring(p + 1).trim());
line = in.readLine();
}
}
pre.put("uri", uri);
} catch (IOException ioe) {
throw new ResponseException(Response.Status.INTERNAL_ERROR, "SERVER INTERNAL ERROR: IOException: " + ioe.getMessage(), ioe);
}
}
1.Http协议第一行是Method URI HTTP_VERSION
2.后面每行都是KEY:VALUE格式的header
3.uri需要经过URIDecode处理后才能使用
4.uri中如果包含？则表示有param，httprequest的param一般表现为:/index.jsp?username=xiaoming&id=2
下面是处理cookie，不过这里cookie的实现较为简单，所以跳过。之后是serve方法，serve方法提供了用户自己实现httpserver具体逻辑的很好接口。在NanoHttpd中的serve方法实现了一个默认的简单处理功能。
[java]
view plain
copy
/**
* Override this to customize the server.
* <p/>
* <p/>
* (By default, this delegates to serveFile() and allows directory listing.)
*
* @param session The HTTP session
* @return HTTP response, see class Response for details
*/
public Response serve(IHTTPSession session) {
Map<String, String> files = new HashMap<String, String>();
Method method = session.getMethod();
if (Method.PUT.equals(method) || Method.POST.equals(method)) {
try {
session.parseBody(files);
} catch (IOException ioe) {
return new Response(Response.Status.INTERNAL_ERROR, MIME_PLAINTEXT, "SERVER INTERNAL ERROR: IOException: " + ioe.getMessage());
} catch (ResponseException re) {
return new Response(re.getStatus(), MIME_PLAINTEXT, re.getMessage());
}
}
Map<String, String> parms = session.getParms();
parms.put(QUERY_STRING_PARAMETER, session.getQueryParameterString());
return serve(session.getUri(), method, session.getHeaders(), parms, files);
}
这个默认的方法处理了PUT和POST方法，如果不是就返回默认的返回值。
parseBody方法中使用了tmpFile的方法保存httpRequest的content信息，然后处理，具体逻辑就不细说了，不是一个典型的实现。
最后看一下发response的逻辑：
[java]
view plain
copy
/**
* Sends given response to the socket.
*/
protected void send(OutputStream outputStream) {
String mime = mimeType;
SimpleDateFormat gmtFrmt = new SimpleDateFormat("E, d MMM yyyy HH:mm:ss 'GMT'", Locale.US);
gmtFrmt.setTimeZone(TimeZone.getTimeZone("GMT"));
try {
if (status == null) {
throw new Error("sendResponse(): Status can't be null.");
}
PrintWriter pw = new PrintWriter(outputStream);
pw.print("HTTP/1.1 " + status.getDescription() + " \r\n");
if (mime != null) {
pw.print("Content-Type: " + mime + "\r\n");
}
if (header == null || header.get("Date") == null) {
pw.print("Date: " + gmtFrmt.format(new Date()) + "\r\n");
}
if (header != null) {
for (String key : header.keySet()) {
String value = header.get(key);
pw.print(key + ": " + value + "\r\n");
}
}
sendConnectionHeaderIfNotAlreadyPresent(pw, header);
if (requestMethod != Method.HEAD && chunkedTransfer) {
sendAsChunked(outputStream, pw);
} else {
int pending = data != null ? data.available() : 0;
sendContentLengthHeaderIfNotAlreadyPresent(pw, header, pending);
pw.print("\r\n");
pw.flush();
sendAsFixedLength(outputStream, pending);
}
outputStream.flush();
safeClose(data);
} catch (IOException ioe) {
// Couldn't write? No can do.
}
}
发送response的步骤如下：
1.设置mimeType和Time等内容。
2.创建一个PrintWriter，按照HTTP协议依次开始写入内容
3.第一行是HTTP的返回码
4.然后是content-Type
5.然后是Date时间
6.之后是其他的HTTP Header
7.设置Keep-Alive的Header，Keep-Alive是Http1.1的新特性，作用是让客户端和服务器端之间保持一个长链接。
8.如果客户端指定了ChunkedEncoding则分块发送response，Chunked Encoding是Http1.1的又一新特性。一般在response的body比较大的时候使用，server端会首先发送response的HEADER，然后分块发送response的body，每个分块都由chunk length\r\n和chunk data\r\n组成，最后由一个0\r\n结束。
[java]
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private void sendAsChunked(OutputStream outputStream, PrintWriter pw) throws IOException {
pw.print("Transfer-Encoding: chunked\r\n");
pw.print("\r\n");
pw.flush();
int BUFFER_SIZE = 16 * 1024;
byte[] CRLF = "\r\n".getBytes();
byte[] buff = new byte[BUFFER_SIZE];
int read;
while ((read = data.read(buff)) > 0) {
outputStream.write(String.format("%x\r\n", read).getBytes());
outputStream.write(buff, 0, read);
outputStream.write(CRLF);
}
outputStream.write(String.format("0\r\n\r\n").getBytes());
}
9.如果没指定ChunkedEncoding则需要指定Content-Length来让客户端指定response的body的size，然后再一直写body直到写完为止。
[java]
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private void sendAsFixedLength(OutputStream outputStream, int pending) throws IOException {
if (requestMethod != Method.HEAD && data != null) {
int BUFFER_SIZE = 16 * 1024;
byte[] buff = new byte[BUFFER_SIZE];
while (pending > 0) {
int read = data.read(buff, 0, ((pending > BUFFER_SIZE) ? BUFFER_SIZE : pending));
if (read <= 0) {
break;
}
outputStream.write(buff, 0, read);
pending -= read;
}
}
}
最后总结下实现HttpServer最重要的几个部分：
1.能够accept tcp连接并从socket中读取request数据
2.把request的比特流转换成request对象中的对象数据
3.根据http协议的规范处理http request
4.产生http response再写回到socket中传给client。
@ http://blog.csdn.net/mrtitan/article/details/24332429
NanoHttpd是Github上的一个开源项目，号称只用一个java文件就能创建一个http server，我将通过分析NanoHttpd的源码解析如何开发自己的HttpServer。Github 地址：https://github.com/NanoHttpd/nanohttpd
在开始前首先简单说明HttpServer的基本要素：
1.能接受HttpRequest并返回HttpResponse
2.满足一个Server的基本特征，能够长时间运行
关于Http协议一般HttpServer都会声明支持Http协议的哪些特性，nanohttpd作为一个轻量级的httpserver只实现了最简单、最常用的功能，不过我们依然可以从中学习很多。
首先看下NanoHttpd类的start函数
[java]
view plain
copy
public void start() throws IOException {
myServerSocket = new ServerSocket();
myServerSocket.bind((hostname != null) ? new InetSocketAddress(hostname, myPort) : new InetSocketAddress(myPort));
myThread = new Thread(new Runnable() {
@Override
public void run() {
do {
try {
final Socket finalAccept = myServerSocket.accept();
registerConnection(finalAccept);
finalAccept.setSoTimeout(SOCKET_READ_TIMEOUT);
final InputStream inputStream = finalAccept.getInputStream();
asyncRunner.exec(new Runnable() {
@Override
public void run() {
OutputStream outputStream = null;
try {
outputStream = finalAccept.getOutputStream();
TempFileManager tempFileManager = tempFileManagerFactory.create();
HTTPSession session = new HTTPSession(tempFileManager, inputStream, outputStream, finalAccept.getInetAddress());
while (!finalAccept.isClosed()) {
session.execute();
}
} catch (Exception e) {
// When the socket is closed by the client, we throw our own SocketException
// to break the "keep alive" loop above.
if (!(e instanceof SocketException && "NanoHttpd Shutdown".equals(e.getMessage()))) {
e.printStackTrace();
}
} finally {
safeClose(outputStream);
safeClose(inputStream);
safeClose(finalAccept);
unRegisterConnection(finalAccept);
}
}
});
} catch (IOException e) {
}
} while (!myServerSocket.isClosed());
}
});
myThread.setDaemon(true);
myThread.setName("NanoHttpd Main Listener");
myThread.start();
}
1.创建ServerSocket，bind制定端口
2.创建主线程，主线程负责和client建立连接
3.建立连接后会生成一个runnable对象放入asyncRunner中，asyncRunner.exec会创建一个线程来处理新生成的连接。
4.新线程首先创建了一个HttpSession，然后while(true)的执行httpSession.exec。
这里介绍下HttpSession的概念，HttpSession是java里Session概念的实现，简单来说一个Session就是一次httpClient->httpServer的连接，当连接close后session就结束了，如果没结束则session会一直存在。这点从这里的代码也能看到：如果socket不close或者exec没有抛出异常（异常有可能是client段断开连接）session会一直执行exec方法。
一个HttpSession中存储了一次网络连接中server应该保存的信息，比如：URI，METHOD，PARAMS，HEADERS，COOKIES等。
5.这里accept一个client的socket就创建一个独立线程的server模型是ThreadServer模型，特点是一个connection就会创建一个thread，是比较简单、常见的socket server实现。缺点是在同时处理大量连接时线程切换需要消耗大量的资源，如果有兴趣可以了解更加高效的NIO实现方式。
当获得client的socket后自然要开始处理client发送的httprequest。
Http Request Header的parse：
[plain]
view plain
copy
// Read the first 8192 bytes.
// The full header should fit in here.
// Apache's default header limit is 8KB.
// Do NOT assume that a single read will get the entire header at once!
byte[] buf = new byte[BUFSIZE];
splitbyte = 0;
rlen = 0;
{
int read = -1;
try {
read = inputStream.read(buf, 0, BUFSIZE);
} catch (Exception e) {
safeClose(inputStream);
safeClose(outputStream);
throw new SocketException("NanoHttpd Shutdown");
}
if (read == -1) {
// socket was been closed
safeClose(inputStream);
safeClose(outputStream);
throw new SocketException("NanoHttpd Shutdown");
}
while (read > 0) {
rlen += read;
splitbyte = findHeaderEnd(buf, rlen);
if (splitbyte > 0)
break;
read = inputStream.read(buf, rlen, BUFSIZE - rlen);
}
}
1.读取socket数据流的前8192个字节，因为http协议中头部最长为8192
2.通过findHeaderEnd函数找到header数据的截止位置，并把位置保存到splitbyte内。
[java]
view plain
copy
if (splitbyte < rlen) {
inputStream.unread(buf, splitbyte, rlen - splitbyte);
}
parms = new HashMap<String, String>();
if(null == headers) {
headers = new HashMap<String, String>();
}
// Create a BufferedReader for parsing the header.
BufferedReader hin = new BufferedReader(new InputStreamReader(new ByteArrayInputStream(buf, 0, rlen)));
// Decode the header into parms and header java properties
Map<String, String> pre = new HashMap<String, String>();
decodeHeader(hin, pre, parms, headers);
1.使用unread函数将之前读出来的body pushback回去，这里使用了pushbackstream，用法比较巧妙，因为一旦读到了header的尾部就需要进入下面的逻辑来判断是否需要再读下去了，而不应该一直读，读到没有数据为止
2.decodeHeader，将byte的header转换为java对象
[java]
view plain
copy
private int findHeaderEnd(final byte[] buf, int rlen) {
int splitbyte = 0;
while (splitbyte + 3 < rlen) {
if (buf[splitbyte] == '\r' && buf[splitbyte + 1] == '\n' && buf[splitbyte + 2] == '\r' && buf[splitbyte + 3] == '\n') {
return splitbyte + 4;
}
splitbyte++;
}
return 0;
}
1.http协议规定header和body之间使用两个回车换行分割
[java]
view plain
copy
private void decodeHeader(BufferedReader in, Map<String, String> pre, Map<String, String> parms, Map<String, String> headers)
throws ResponseException {
try {
// Read the request line
String inLine = in.readLine();
if (inLine == null) {
return;
}
StringTokenizer st = new StringTokenizer(inLine);
if (!st.hasMoreTokens()) {
throw new ResponseException(Response.Status.BAD_REQUEST, "BAD REQUEST: Syntax error. Usage: GET /example/file.html");
}
pre.put("method", st.nextToken());
if (!st.hasMoreTokens()) {
throw new ResponseException(Response.Status.BAD_REQUEST, "BAD REQUEST: Missing URI. Usage: GET /example/file.html");
}
String uri = st.nextToken();
// Decode parameters from the URI
int qmi = uri.indexOf('?');
if (qmi >= 0) {
decodeParms(uri.substring(qmi + 1), parms);
uri = decodePercent(uri.substring(0, qmi));
} else {
uri = decodePercent(uri);
}
// If there's another token, it's protocol version,
// followed by HTTP headers. Ignore version but parse headers.
// NOTE: this now forces header names lowercase since they are
// case insensitive and vary by client.
if (st.hasMoreTokens()) {
String line = in.readLine();
while (line != null && line.trim().length() > 0) {
int p = line.indexOf(':');
if (p >= 0)
headers.put(line.substring(0, p).trim().toLowerCase(Locale.US), line.substring(p + 1).trim());
line = in.readLine();
}
}
pre.put("uri", uri);
} catch (IOException ioe) {
throw new ResponseException(Response.Status.INTERNAL_ERROR, "SERVER INTERNAL ERROR: IOException: " + ioe.getMessage(), ioe);
}
}
1.Http协议第一行是Method URI HTTP_VERSION
2.后面每行都是KEY:VALUE格式的header
3.uri需要经过URIDecode处理后才能使用
4.uri中如果包含？则表示有param，httprequest的param一般表现为:/index.jsp?username=xiaoming&id=2
下面是处理cookie，不过这里cookie的实现较为简单，所以跳过。之后是serve方法，serve方法提供了用户自己实现httpserver具体逻辑的很好接口。在NanoHttpd中的serve方法实现了一个默认的简单处理功能。
[java]
view plain
copy
/**
* Override this to customize the server.
* <p/>
* <p/>
* (By default, this delegates to serveFile() and allows directory listing.)
*
* @param session The HTTP session
* @return HTTP response, see class Response for details
*/
public Response serve(IHTTPSession session) {
Map<String, String> files = new HashMap<String, String>();
Method method = session.getMethod();
if (Method.PUT.equals(method) || Method.POST.equals(method)) {
try {
session.parseBody(files);
} catch (IOException ioe) {
return new Response(Response.Status.INTERNAL_ERROR, MIME_PLAINTEXT, "SERVER INTERNAL ERROR: IOException: " + ioe.getMessage());
} catch (ResponseException re) {
return new Response(re.getStatus(), MIME_PLAINTEXT, re.getMessage());
}
}
Map<String, String> parms = session.getParms();
parms.put(QUERY_STRING_PARAMETER, session.getQueryParameterString());
return serve(session.getUri(), method, session.getHeaders(), parms, files);
}
这个默认的方法处理了PUT和POST方法，如果不是就返回默认的返回值。
parseBody方法中使用了tmpFile的方法保存httpRequest的content信息，然后处理，具体逻辑就不细说了，不是一个典型的实现。
最后看一下发response的逻辑：
[java]
view plain
copy
/**
* Sends given response to the socket.
*/
protected void send(OutputStream outputStream) {
String mime = mimeType;
SimpleDateFormat gmtFrmt = new SimpleDateFormat("E, d MMM yyyy HH:mm:ss 'GMT'", Locale.US);
gmtFrmt.setTimeZone(TimeZone.getTimeZone("GMT"));
try {
if (status == null) {
throw new Error("sendResponse(): Status can't be null.");
}
PrintWriter pw = new PrintWriter(outputStream);
pw.print("HTTP/1.1 " + status.getDescription() + " \r\n");
if (mime != null) {
pw.print("Content-Type: " + mime + "\r\n");
}
if (header == null || header.get("Date") == null) {
pw.print("Date: " + gmtFrmt.format(new Date()) + "\r\n");
}
if (header != null) {
for (String key : header.keySet()) {
String value = header.get(key);
pw.print(key + ": " + value + "\r\n");
}
}
sendConnectionHeaderIfNotAlreadyPresent(pw, header);
if (requestMethod != Method.HEAD && chunkedTransfer) {
sendAsChunked(outputStream, pw);
} else {
int pending = data != null ? data.available() : 0;
sendContentLengthHeaderIfNotAlreadyPresent(pw, header, pending);
pw.print("\r\n");
pw.flush();
sendAsFixedLength(outputStream, pending);
}
outputStream.flush();
safeClose(data);
} catch (IOException ioe) {
// Couldn't write? No can do.
}
}
发送response的步骤如下：
1.设置mimeType和Time等内容。
2.创建一个PrintWriter，按照HTTP协议依次开始写入内容
3.第一行是HTTP的返回码
4.然后是content-Type
5.然后是Date时间
6.之后是其他的HTTP Header
7.设置Keep-Alive的Header，Keep-Alive是Http1.1的新特性，作用是让客户端和服务器端之间保持一个长链接。
8.如果客户端指定了ChunkedEncoding则分块发送response，Chunked Encoding是Http1.1的又一新特性。一般在response的body比较大的时候使用，server端会首先发送response的HEADER，然后分块发送response的body，每个分块都由chunk length\r\n和chunk data\r\n组成，最后由一个0\r\n结束。
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private void sendAsChunked(OutputStream outputStream, PrintWriter pw) throws IOException {
pw.print("Transfer-Encoding: chunked\r\n");
pw.print("\r\n");
pw.flush();
int BUFFER_SIZE = 16 * 1024;
byte[] CRLF = "\r\n".getBytes();
byte[] buff = new byte[BUFFER_SIZE];
int read;
while ((read = data.read(buff)) > 0) {
outputStream.write(String.format("%x\r\n", read).getBytes());
outputStream.write(buff, 0, read);
outputStream.write(CRLF);
}
outputStream.write(String.format("0\r\n\r\n").getBytes());
}
9.如果没指定ChunkedEncoding则需要指定Content-Length来让客户端指定response的body的size，然后再一直写body直到写完为止。
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private void sendAsFixedLength(OutputStream outputStream, int pending) throws IOException {
if (requestMethod != Method.HEAD && data != null) {
int BUFFER_SIZE = 16 * 1024;
byte[] buff = new byte[BUFFER_SIZE];
while (pending > 0) {
int read = data.read(buff, 0, ((pending > BUFFER_SIZE) ? BUFFER_SIZE : pending));
if (read <= 0) {
break;
}
outputStream.write(buff, 0, read);
pending -= read;
}
}
}
最后总结下实现HttpServer最重要的几个部分：
1.能够accept tcp连接并从socket中读取request数据
2.把request的比特流转换成request对象中的对象数据
3.根据http协议的规范处理http request
4.产生http response再写回到socket中传给client。
@ http://blog.csdn.net/mrtitan/article/details/24332429
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