《Android版Web服务器实现(二)使用服务来监听HTTP请求》一文实现了HTTP请求的监听，那么我们要如何作出响应呢？在响应时，有几种情况。
1、请求的方法不支持。比如服务端仅支持了GET/POST方法，而请求却有DELETE等，此时回复501。
2、请求的资源不存在。在服务端不存在该资源文件，将回复404页面。
3、请求的类型不支持。服务端可能存在该资源，但是该资源的类型没有支持，将回复404.7。
4、请求正常。服务端将相应的资源回复给客户端。
5、其他情况。
下面是依据这些情况的代码实现。
SessionThread.java
package com.sparkle.webservice;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import android.util.Log;
public class SessionThread extends Thread {
private Socket _clientSocket = null;
private final int BUFFER_MAX = 8192;
private DataHandle _dataHandle = null;
private MyLog _myLog = new MyLog(getClass().getName());
public SessionThread(Socket clientSocket) {
this._clientSocket = clientSocket;
}
public void closeSocket() {
if (_clientSocket == null) {
return;
}
try {
_clientSocket.close();
} catch (IOException e) {
_myLog.e(e.getMessage());
}
}
public void run() {
try {
InputStream socketInput = _clientSocket.getInputStream();
byte[] buffer = new byte[BUFFER_MAX];
socketInput.read(buffer);
_dataHandle = new DataHandle(buffer);
byte[] content = _dataHandle.fetchContent();
sendResponse(_clientSocket, content);
} catch (Exception e) {
_myLog.l(Log.DEBUG, "Exception in TcpListener");
}
}
private void sendResponse(Socket clientSocket, byte[] content) {
try {
OutputStream socketOut = clientSocket.getOutputStream();
byte[] header = _dataHandle.fetchHeader(content.length);
socketOut.write(header);
socketOut.write(content);
socketOut.close();
clientSocket.close();
} catch (Exception e) {
}
}
}
注：
1、在收到请求后，新建一个SessionThread来处理请求（在上一篇中有说到）。
2、SessionThread建立后，在run中新建DataHandle来处理数据，具体请参看后文代码。
3、在sendResponse来回应请求。
4、在响应时，先发送header，再发送content来响应
DataHandle.java
package com.sparkle.webservice;
import java.io.UnsupportedEncodingException;
import com.sparkle.io.FileSp;
import android.annotation.SuppressLint;
import android.util.Log;
public class DataHandle {
private String _receiveInfo = "";
private HttpHeader _httpHeader = null;
private String _encoding = "utf-8";
private String _serverName = "Simple Web Server";
private String _responseCode = "200 OK";
private String _contentType = "text/html";
public DataHandle(byte[] recieveData) {
try {
this._receiveInfo = new String(recieveData, _encoding);
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
_httpHeader = new HttpHeader(_receiveInfo);
}
public byte[] fetchContent() {
byte[] backData = null;
if (!isSupportMethod()) {
backData = fetchNotSupportMethodBack();
return backData;
}
String filePath = fetchFilePath();
boolean hasFile=FileSp.isExist(filePath);
Log.e("FilePath", filePath+" "+hasFile);
if (!hasFile) {
backData = fetchNotFoundBack();
return backData;
}
if (!isSupportExtension()) {
backData = fetchNotSupportFileBack();
return backData;
}
backData = fetchBackFromFile(filePath);
return backData;
}
public byte[] fetchHeader(int contentLength) {
byte[] header = null;
try {
header = ("HTTP/1.1 " + _responseCode + "\r\n"
+ "Server: "+ _serverName + "\r\n"
+ "Content-Length: " + contentLength+ "\r\n"
+ "Connection: close\r\n"
+ "Content-Type: "+ _contentType + ";charset="+_encoding+"\r\n\r\n").getBytes(_encoding);
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return header;
}
@SuppressLint("DefaultLocale")
private boolean isSupportMethod() {
String method = _httpHeader.getMethod();
if (method == null || method.length() <= 0) {
return false;
}
method = method.toUpperCase();
if (method.equals("GET") || method.equals("POST")) {
return true;
}
return false;
}
private boolean isSupportExtension() {
String contentType = _httpHeader.getContentType();
if (contentType == null || contentType.length() <= 0) {
return false;
}
_contentType=contentType;
return true;
}
private byte[] fetchNotSupportMethodBack() {
byte[] backData = null;
String notImplementMethod = "<html><head><meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"></head><body><h2>"
+ _serverName
+ "</h2><div>501 - Method Not Implemented</div></body></html>";
try {
backData = notImplementMethod.getBytes(_encoding);
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return backData;
}
private byte[] fetchNotSupportFileBack() {
byte[] backData = null;
String notImplementMethod = "<html><head><meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"></head><body><h2>"
+ _serverName
+ "</h2><div>404.7 Not Found(Type Not Support)</div></body></html>";
try {
backData = notImplementMethod.getBytes(_encoding);
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return backData;
}
private byte[] fetchBackFromFile(String filePath) {
byte[] content = null;
content = FileSp.read(filePath);
return content;
}
private String fetchFilePath() {
String root = Defaults.getRoot();
String fileName = _httpHeader.getFileName();
String filePath = "";
if (fileName.startsWith("/") || fileName.startsWith("\\")) {
filePath = root + fileName.substring(1);
} else {
filePath = root + fileName;
}
return filePath;
}
private byte[] fetchNotFoundBack() {
byte[] notFoundData = null;
String notFoundStr = "<html><head><meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"></head><body><h2>"
+ _serverName + "</h2><div>404 - Not Found</div></body></html>";
try {
notFoundData = notFoundStr.getBytes(_encoding);
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return notFoundData;
}
}
注：
1、isSupportMethod判断是否是支持的方法，如果不支持，从fetchNotSupportMethodBack获取数据进行响应。
2、判断请求的资源是否存在，如果不存在，从fetchNotFoundBack获取数据进行响应。
3、isSupportExtension判断是否是支持的数据类型，如果不支持，从fetchNotSupportFileBack获取数据进行响应。
4、请求方法支持、请求资源存在，且请求类型支持，将从fetchBackFromFile获取数据进行响应。
在对HTTP作出相应的响应之后，现在就剩下如果在界面中实现相应的控制了，具体请看下一篇。
转载请注明出处：Android版Web服务器实现(三)HTTP响应