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使用J2ME中的page进行编码转化

时间:2009-12-23 15:42来源:未知 作者:admin 点击:
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一、摘要 根据xinshouj2me在j2me版提出的“httpconnection网络连接的问题”,本人分析了一下:由于www.163.com上的页面编码为gb2312,所以使用utf8读取由于编码方式不同会得到乱码。于是本人根

   一、摘要
  
  根据xinshouj2me在j2me版提出的“httpconnection网络连接的问题”,本人分析了一下:由于www.163.com上的页面编码为gb2312,所以使用utf8读取由于编码方式不同会得到乱码。于是本人根据page的编码灵活进行编码转化,在此与大家共享、讨论。
  
  二、代码分析
  
  1.HttpConnectionHandler接口类
  最好根据page的编码灵活进行编码转化,于是本人定义了一个HttpConnectionHandler接口类:
  
  HttpConnectionHandler.Java
  package com.bjinfotech.practice.j2me.httpConnection;
  
  import java.util.Hashtable;
  import javax.microedition.io.HttpConnection;
  
  /**
   * Http连接处理器接口
   * @author cleverpig
   *
   */
  public interface HttpConnectionHandler {
          //http请求常量
          public static final String RQH_HOST="X-Online-Host";
          public static final String RQH_ACCEPT="Accept";
          public static final String RQH_CONTENT_LANGUAGE="Content-Language";
          public static final String RQH_CONTENT_TYPE="Content-Type";
          public static final String RQH_CONNECTION_OPTION="Connection";
          //http回应常量
          public static final String RSH_DATE="Date";
          public static final String RSH_SERVER="Server";
          public static final String RSH_MODIFIEDDATE="Last-Modified";
          public static final String RSH_CONTENT_ENCODING="Content-Encoding";
          public static final String RSH_CONTENT_LENGTH="Content-Length";
          public static final String RSH_CONTENT_TYPE="Content-Type";
          
          public boolean putRequestHeaderProperty(
                          HttpConnection conn,
                          String key,
                          String keyValue);
          
          public String getResponseHeaderProperty(
                          HttpConnection conn,
                          String key);
          
          public boolean setRequestMethod(
                          HttpConnection conn,
                          String methodName);
          
          public boolean putRequestHeader(
                          HttpConnection conn,
                          Hashtable propertiesPair);
          
          public Hashtable getResponseHeader(
                          HttpConnection conn,
                          String[] propertyNames);
          
          public boolean sendRequestData(
                          HttpConnection conn,
                          Object sendData);
          
          public Object getResponseData(HttpConnection conn);
          
  }
  
  2.Html_HttpConnectionHandlerImpl类
  
  根据HttpConnectionHandler接口规范实现了该接口――HTML_HttpConnectionHandlerImpl类。
  
  HTML_HttpConnectionHandlerImpl.java
  package com.bjinfotech.practice.j2me.httpConnection;
  
  import java.io.DataOutputStream;
  import java.io.DataInputStream;
  import java.util.Hashtable;
  import java.util.Vector;
  import java.util.Enumeration;
  import javax.microedition.io.HttpConnection;
  
  /**
   * http连接处理器实现
   * @author cleverpig
   *
   */
  public class HTML_HttpConnectionHandlerImpl implements HttpConnectionHandler{
          private String message="";
          
          public HTML_HttpConnectionHandlerImpl(){
          }
          
          public boolean putRequestHeaderProperty(
                          HttpConnection conn,
                          String key,
                          String keyValue){
                  message="";
                  try{
                          conn.setRequestProperty(key,keyValue);
                          return true;
                  }
                  catch(Exception ex){
                          message=ex.getMessage();
                  }
                  return false;
          }
          
          public String getResponseHeaderProperty(
                          HttpConnection conn,
                          String key){
                  return conn.getRequestProperty(key);
          }
          
          public boolean putRequestHeader(
                          HttpConnection conn,
                          Hashtable propertiesPair){
                  Enumeration keyEnumer=propertiesPair.keys();
                  boolean result=true;
                  while(keyEnumer.hasMoreElements()){
                          String keyName=(String)keyEnumer.nextElement();
                          String keyValue=(String)propertiesPair.get(keyName);
                          if (putRequestHeaderProperty(conn,keyName,keyValue)==false){
                                  result=false;
                          }
                  }
                  return result;
          }
          
          public boolean setRequestMethod(
                          HttpConnection conn,
                          String methodName){
                  message="";
                  try{
                          conn.setRequestMethod(methodName);
                          return true;
                  }
                  catch(Exception ex){
                          message=ex.getMessage();
                          return false;
                  }
          }
          
          public Hashtable getResponseHeader(
                          HttpConnection conn,
                          String[] propertyNames){
                  Hashtable result=new Hashtable();
                  for(int i=0;i<propertyNames.length;i++){
                          String keyValue=conn.getRequestProperty(propertyNames[i]);
                          result.put(propertyNames[i],keyValue);
                  }
                  return result;
          }
          
          public boolean sendRequestData(
                          HttpConnection conn,
                          Object sendData){
                  message="";
                  try{
                          DataOutputStream os=conn.openDataOutputStream();
                          os.writeUTF((String)(sendData));
                          os.flush();
                          return true;
                  }
                  catch(Exception ex){
                          message=ex.getMessage();
                          return false;
                  }
          }
          
          public Object getResponseData(HttpConnection conn){
                  DataInputStream is=null;
                  message="";
                  try{
                          is=conn.openDataInputStream();
                  }
                  catch(Exception ex){
                          message=ex.getMessage();
                          return null;
                  }
                  
                  byte[] data=null;
                  String type=getResponseHeaderProperty(conn,RSH_CONTENT_TYPE);
                  int len = 0;
                  try{
                          len=Integer.parseInt(getResponseHeaderProperty(conn,RSH_CONTENT_LENGTH));
                  }
                  catch(Exception ex){
                          len=0;
                  }
                  if (len > 0) {
               int actual = 0;
               int bytesread = 0 ;
               data = new byte[len];
               while ((bytesread != len) && (actual != -1)) {
                       try{
                               actual = is.read(data, bytesread, len - bytesread);
                               bytesread += actual;
                       }
                       catch(Exception ex){
                               message=ex.getMessage();
                               return null;
                       }
               }
          } else {
              int ch;
              Vector vbuffer=new Vector();
              try{
                      while ((ch = is.read()) != -1) {
                              vbuffer.addElement(new Integer(ch));
                      }
              }
                         catch(Exception ex){
                                  message=ex.getMessage();
                                  return null;
                         }
              len=vbuffer.size();
              data = new byte[len];
              for(int i=0;i<len;i++){
                      data[i]=((Integer)vbuffer.elementAt(i)).byteValue();
              }
          }
          
          String result=new String(data);
          int flagBeginPosition=result.indexOf("charset=");
          int flagEndPosition=result.indexOf("">",flagBeginPosition);
          if (flagEndPosition>flagBeginPosition){
                  type=result.substring(flagBeginPosition+"charset=".length(),flagEndPosition);
          }
          System.out.println("获得html字符集:"+type);
          if (type!=null){
                  
                  try{
                          result=new String(data,type);
                  }
                  catch(Exception ex){
                          message=ex.getMessage();
                  }
          }
          return result;
          }
          
          public String getMessage(){
                  return message;
          }
          
          
  }
  上面实现类中根据page中的实际编码类型对html字符串进行了编码转化,这样就实现了page编码的灵活转化。
  虽然灵活性加强了,但是对于内存的占用也随之增加了一倍。
  
  三.测试代码
  
  package com.bjinfotech.practice.j2me.httpConnection;
  
  import javax.microedition.midlet.MIDlet;
  import javax.microedition.midlet.MIDletStateChangeException;
  import javax.microedition.io.HttpConnection;
  import javax.microedition.io.Connector;
  import java.util.Hashtable;
  
  public class HttpConnectionMIDlet extends MIDlet {
  
          public HttpConnectionMIDlet() {
                  super();
          }
  
          
          protected void startApp() throws MIDletStateChangeException {
                  HTML_HttpConnectionHandlerImpl handler=new HTML_HttpConnectionHandlerImpl();
                  try{
                          String host="10.11.3.99";
                          String url="http://10.11.3.99:8080/test_gbk.html";
  //                        String url="http://10.11.3.99:8080/test_gb2312.html";
  //                        String url="http://10.11.3.99:8080/test_utf8.html";
                          
                          HttpConnection conn=(HttpConnection)Connector.open(url);
                          if (conn.getResponseCode()==HttpConnection.HTTP_OK){
                                  System.out.println("建立连接成功");
                                  
                                  Hashtable requestHeaderPair=new Hashtable();
                                  requestHeaderPair.put(
                                                  HTML_HttpConnectionHandlerImpl.RQH_HOST,
                                                  host);
                                  requestHeaderPair.put(
                                                  HTML_HttpConnectionHandlerImpl.RQH_CONTENT_TYPE,
                                                  "application/octet-stream");
                                  requestHeaderPair.put(
                                                  HTML_HttpConnectionHandlerImpl.RQH_CONTENT_LANGUAGE,
                                                  "en-US");
                                  requestHeaderPair.put(
                                                  HTML_HttpConnectionHandlerImpl.RQH_ACCEPT,
                                                  "application/octet-stream");
                                  requestHeaderPair.put(
                                                  HTML_HttpConnectionHandlerImpl.RQH_CONNECTION_OPTION,
                                                  "Keep-Alive");
                                  handler.putRequestHeader(conn,requestHeaderPair);
                                  handler.setRequestMethod(conn,HttpConnection.GET);
                                  handler.sendRequestData(conn,"GET / HTTP/1.1");
                                  if (conn.getResponseCode()==HttpConnection.HTTP_OK){
                                          System.out.println("发送请求成功");
                                          
                                          System.out.println("获得回应数据");
                                          String reponseData=(String)handler.getResponseData(conn);
                                          System.out.println(reponseData);
                                  }
                                  else{
                                          System.out.println("发送请求失败");
                                          System.out.println("错误信息:"+handler.getMessage());
                                  }
                          }
                          else{
                                  System.out.println("建立连接失败");
                          }
                  }
                  catch(Exception ex){
                          System.out.println("错误信息:"+handler.getMessage());
                          ex.printStackTrace();
                  }
                  
          }       
          protected void pauseApp() {
  
          }
          protected void destroyApp(boolean arg0) throws MIDletStateChangeException {            
          }
  
  }
  
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