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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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