使用J2ME中的page进行编码转化
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 {
}
}