this is a extra element for clear the floated element
Java:用Socket类实现HTTP协议客户端应用
  • 09/30
  • 2007
java/jsp | Linux 3166 次查看
  btw, 这个程序后面的例子是我这几天用的一个作弊程序... :P

  Http客户端程序已集成在Java语言中,可以通过URLConnection类调用。遗憾的

  是,由于SUN没有公布Http客户程序的源码,它实现的细节仍是一个谜。本文根据HTTP

  协议规范,用Java.net.Socket类实现一个HTTP协议客户端程序。

  1.Socket类:

  了解TCP/IP协议集通信的读者知道,协议间的通信是通过Socket完成的。在

  Java.net包中,Socket类就是对Socket的具体实现。它通过连接到主机后,返回一个

  I/O流,实现协议间的信息交换。

  2 . HTTP协议

  HTTP协议同其它TCP/IP协议集中的协议一样,是遵循客户/服务器模型工作的。客

  户端发往服务端的信息格式如下:

  ------------------------------

  请求方法 URL HTTP协议的版本号

  提交的元信息

  **空行**

  实体

  ------------------------------

  请求方法是对这次连接工作的说明,目前HTTP协议已经发展到1.1版,它包括GET、

  HEAD、POST、DELETE、OPTIONS、TRACE、PUT七种。元信息是关于当前请求的信息。通

  过分析元信息,可以检查实体数据是否完整,接收过程是否出错,类型是否匹配等。元

  信息的引入使HTTP协议通信更加稳妥可靠。实体是请求的具体内容。

  将上述报文发往Web服务器,如果成功,应答格式如下:

  --------------------------------

  HTTP协议的版本号 应答状态码 应答状态码说明

  接收的元信息

  **空行**

  实体

  --------------------------------

  以上报文发向客户端,并且接收成功,彼此间关闭连接,完成一次握手。

  下面用最常用的GET方法,来说明具体的报文应用

  ----------------------------------

  GET http://www.youhost.com HTTP/1.0

  accept: www/source; text/html; image/gif; image/jpeg; */*

  User_Agent: myAgent

  **空行**

  -----------------------------------

  这个报文是向www.youhost.com主机请求一个缺省HTML文档。客户端HTTP协议版本

  号是1.0版,元信息包括可接收的文件格式,用户代理,每一段之间用回车换行符分

  隔,最后以一个空行结束。发向服务器后,如果执行过程正常,服务器返回以下代码:

  ------------------------------------

  HTTP/1.1 200 OK

  Date: Tue, 14 Sep 1999 02:19:57 GMT

  Server: Apache/1.2.6

  Connection: close

  Content-Type: text/html

  **空行**

  <html><head>...</head><body>...</body></html>

  ------------------------------------

  HTTP/1.1表示这个HTTP服务器是1.1版,200是服务器对客户请求的应答状态码,OK

  是对应答状态码的解释,之后是这个文档的元信息和文档正文。(相关应答状态码和元

  信息的解释请参阅Inetrnet标准草案:RFC2616)。

  Http.java

  import java.net.*;

  import java.io.*;

  import java.util.Properties;

  import java.util.Enumeration;

  public class Http {

  protected Socket client;

  protected BufferedOutputStream sender;

  protected BufferedInputStream receiver;

  protected ByteArrayInputStream byteStream;

  protected URL target;

  private int responseCode=-1;

  private String responseMessage="";

  private String serverVersion="";

  private Properties header = new Properties();

  public Http() { }

  public Http(String url) {

  GET(url) ;

  }

  /* GET方法根据URL,会请求文件、数据库查询结果、程序运行结果等多种内容 */

  public void GET(String url) {

  try {

  checkHTTP(url);

  openServer(target.getHost(),target.getPort() );

  String cmd = "GET "+ getURLFormat(target) +" HTTP/1.0

  "

  + getBaseHeads()+"

  ";

  sendMessage(cmd);

  receiveMessage();

  } catch(ProtocolException p) {

  p.printStackTrace();

  return;

  } catch(UnknownHostException e) {

  e.printStackTrace();

  return;

  } catch(IOException i) {

  i.printStackTrace();

  return;

  }

  }

  /*

  * HEAD方法只请求URL的元信息,不包括URL本身。若怀疑本机和服务器上的

  * 文件相同,用这个方法检查最快捷有效。

  */

  public void HEAD(String url) {

  try {

  checkHTTP(url);

  openServer(target.getHost(),target.getPort() );

  String cmd = "HEAD "+getURLFormat(target)+" HTTP/1.0

  "

  +getBaseHeads()+"

  ";

  sendMessage(cmd);

  receiveMessage();

  }catch(ProtocolException p) {

  p.printStackTrace();

  return;

  }catch(UnknownHostException e) {

  e.printStackTrace();

  return;

  }catch(IOException i) {

  i.printStackTrace();

  return;

  }

  }

  /*

  * POST方法是向服务器传送数据,以便服务器做出相应的处理。例如网页上常用的

  * 提交表格。

  */

  public void POST(String url,String content) {

  try {

  checkHTTP(url);

  openServer(target.getHost(),target.getPort() );

  String cmd = "POST "+ getURLFormat(target) +"HTTP/1.0

  "+getBaseHeads();

  cmd += "Content-type: application/x-www-form-urlencoded

  ";

  cmd += "Content-length: " + content.length() + "

  ";

  cmd += content+"

  ";

  sendMessage(cmd);

  receiveMessage();

  }catch(ProtocolException p) {

  p.printStackTrace();

  return;

  }catch(UnknownHostException e) {

  e.printStackTrace();

  return;

  }catch(IOException i) {

  i.printStackTrace();

  return;

  }

  }

  protected void checkHTTP(String url) throws ProtocolException {

  try {

  URL target = new URL(url);

  if(target==null || !target.getProtocol().toUpperCase().equals("HTTP") )

  throw new ProtocolException("这不是HTTP协议");

  this.target = target;

  } catch(MalformedURLException m) {

  throw new ProtocolException("协议格式错误");

  }

  }

  /*

  * 与Web服务器连接。若找不到Web服务器,InetAddress会引发UnknownHostException

  * 异常。若Socket连接失败,会引发IOException异常。

  */

  protected void openServer(String host,int port) throws

  UnknownHostException,IOException {

  header.clear();

  responseMessage=""; responseCode=-1;

  try {

  if(client!=null) closeServer();

  if(byteStream != null) {

  byteStream.close(); byteStream=null;

  }

  InetAddress address = InetAddress.getByName(host);

  client = new Socket(address,port==-1?80:port);

  sender = new BufferedOutputStream(client.getOutputStream());

  receiver = new BufferedInputStream(client.getInputStream());

  }catch(UnknownHostException u) {

  throw u;

  }catch(IOException i) {

  throw i;

  }

  }

  /* 关闭与Web服务器的连接 */

  protected void closeServer() throws IOException {

  if(client==null) return;

  try {

  client.close(); sender.close(); receiver.close();

  } catch(IOException i) {

  throw i;

  }

  client=null; sender=null; receiver=null;

  }

  protected String getURLFormat(URL target) {

  String spec = "http://"+target.getHost();

  if(target.getPort()!=-1)

  spec+=":"+target.getPort();

  return spec+=target.getFile();

  }

  /* 向Web服务器传送数据 */

  protected void sendMessage(String data) throws IOException{

  sender.write(data.getBytes(),0,data.length());

  sender.flush();

  }

  /* 接收来自Web服务器的数据 */

  protected void receiveMessage() throws IOException{

  byte data[] = new byte[1024];

  int count=0;

  int word=-1;

  // 解析第一行

  while( (word=receiver.read())!=-1 ) {

  if(word==' '||word=='

  ') {

  word=receiver.read();

  if(word=='

  ') word=receiver.read();

  break;

  }

  if(count == data.length) data = addCapacity(data);

  data[count++]=(byte)word;

  }

  String message = new String(data,0,count);

  int mark = message.indexOf(32);

  serverVersion = message.substring(0,mark);

  while( mark<message.length() && message.charAt(mark+1)==32 ) mark++;

  responseCode = Integer.parseInt(message.substring(mark+1,mark+=4));

  responseMessage = message.substring(mark,message.length()).trim();

  // 应答状态码和处理请读者添加

  switch(responseCode) {

  case 400:

  throw new IOException("错误请求");

  case 404:

  throw new FileNotFoundException( getURLFormat(target) );

  case 503:

  throw new IOException("服务器不可用" );

  }

  if(word==-1) throw new ProtocolException("信息接收异常终止");

  int symbol=-1;

  count=0;

  // 解析元信息

  while( word!=' ' && word!='

  ' && word>-1) {

  if(word==' ') word=32;

  if(count==data.length) data = addCapacity(data);

  data[count++] = (byte)word;

  parseLine: {

  while( (symbol=receiver.read()) >-1 ) {

  switch(symbol) {

  case ' ':

  symbol=32; break;

  case ' ':

  case '

  ':

  word = receiver.read();

  if( symbol==' ' && word=='

  ') {

  word=receiver.read();

  if(word==' ') word=receiver.read();

  }

  if( word==' ' || word=='

  ' || word>32) break parseLine;

  symbol=32; break;

  }

  if(count==data.length) data = addCapacity(data);

  data[count++] = (byte)symbol;

  }

  word=-1;

  }

  message = new String(data,0,count);

  mark = message.indexOf(':');

  String key = null;

  if(mark>0) key = message.substring(0,mark);

  mark++;

  while( mark<message.length() && message.charAt(mark)<=32 ) mark++;

  String value = message.substring(mark,message.length() );

  header.put(key,value);

  count=0;

  }

  // 获得正文数据

  while( (word=receiver.read())!=-1) {

  if(count == data.length) data = addCapacity(data);

  data[count++] = (byte)word;

  }

  if(count>0) byteStream = new ByteArrayInputStream(data,0,count);

  data=null;

  closeServer();

  }

  public String getResponseMessage() {

  return responseMessage;

  }

  public int getResponseCode() {

  return responseCode;

  }

  public String getServerVersion() {

  return serverVersion;

  }

  public InputStream getInputStream() {

  return byteStream;

  }

  public synchronized String getHeaderKey(int i) {

  if(i>=header.size()) return null;

  Enumeration enum = header.propertyNames();

  String key = null;

  for(int j=0; j<=i; j++)

  key = (String)enum.nextElement();

  return key;

  }

  public synchronized String getHeaderValue(int i) {

  if(i>=header.size()) return null;

  return header.getProperty(getHeaderKey(i));

  }

  public synchronized String getHeaderValue(String key) {

  return header.getProperty(key);

  }

  protected String getBaseHeads() {

  String inf = "User-Agent: myselfHttp/1.0

  "+

  "Accept: www/source; text/html; image/gif; */*

  ";

  return inf;

  }

  private byte[] addCapacity(byte rece[]){

  byte temp[] = new byte[rece.length+1024];

  System.arraycopy(rece,0,temp,0,rece.length);

  return temp;

  }

  public static void main(String[] args) {

  Http http=new Http();

  //http.GET("http://192.168.1.5");

  int i;

  for (i=0; i<50000; i++) {

  http.GET("http://www.model-dl.com/modelinfo.asp?modelid=101");

  http.POST("http://www.model-dl.com/modelinfo.asp?modelid=101","ratecontd=101&MM_insert=form1");

  }

  }

  }