android端与服务器端的通信交互

之前有人说复制了我编写的类，运行不成功，晕，再次编辑下。

有几点要注意的地方：

1、要在androidMainfest.xml中增加权限

<!-- 使用网络功能所需权限 -->
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" >
</uses-permission>
<uses-permission android:name="android.permission.INTERNET" >
</uses-permission>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" >
</uses-permission>
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" >
</uses-permission>

2、在android3.0前，在UI线程中时可以使用网络传输的，但是，我们都知道，网络传输有延迟，而一旦网络信号不好，我们进行网络传输，就会卡住，android自带的防护机制，当程序卡住超过5秒后，就会自动蹦出个提示框，说XX程序无响应，是否将其关闭。所以，现在的进行网络传输，都要新建一个线程，在线程中操作。

但是，如果我们非要在UI线程下使用网络操作的话，可以采用下面的方法。

在Oncreate()方法中加入者两句代码

StrictMode.ThreadPolicy policy=new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);

接着就可以尽情地使用下面编写的Http类了

一开始跟开发服务器那边的人在商量交互，两边必须说明传输方式，如用post还是get方式，必须一致才行。

对方给出了诸如此类的接口。

http://localhost:8080/CampusService/servlet/sendnews?client=0&user=1&pwd=1&text=123

http://localhost:8080/CampusService/servlet/getnews?client=0&user=1&pwd=1&count=2&from=0

等等之类的，想把信息交互作为一个模块，特地写了下面一个http类，采用post传输方式

package com.example.logic;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import org.apache.http.HttpResponse;
import org.apache.http.HttpVersion;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.mime.MultipartEntity;
import org.apache.http.entity.mime.content.ContentBody;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.entity.mime.content.StringBody;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.CoreProtocolPNames;
import org.apache.http.protocol.HTTP;
import org.json.JSONObject;

import android.content.Context;
import android.os.Environment;

import com.google.gson.JsonArray;

public class Http {
private String base ;
private String basepicture;

public Http(Context context) {
// TODO Auto-generated constructor stub
FileService txt = new FileService(context);
String str = null;
try {
str = txt.read(Environment.getExternalStorageDirectory() + "/ip.txt");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
base = "http://" + str + ":8080/CampusService";
basepicture = "http://" + str + ":8080/CampusService/UploadImg.action";
}
public void upPhoto(String user,String pwd,String type,String str, String path){
HttpClient httpClient = new DefaultHttpClient();
httpClient.getParams().setParameter( CoreProtocolPNames.PROTOCOL_VERSION, HttpVersion.HTTP_1_1 );
HttpPost httpPost = new HttpPost(basepicture);
MultipartEntity postEntity = new MultipartEntity();
// 字符用StringBody

ContentBody cuser = null;
ContentBody cpwd = null;
ContentBody ctype = null;
ContentBody cstr = null;
ContentBody cclient = null;
try {
cuser = new StringBody(user);
cpwd = new StringBody(pwd);
ctype = new StringBody(type);
cstr = new StringBody(str);
cclient = new StringBody("0");

String fileName = "/image.png";
// ContentBody cbFileName = new StringBody( fileName );
// 文件用FileBody，并指定文件类型
File file = new File(path+fileName);
ContentBody cbFileData = new FileBody(file, "image/png");
// 把上面创建的这些Body全部加到Entity里面去。
// 注意他们的key，这些key在Struts2服务器端Action的代码里必须保持一致！！
postEntity.addPart("client",cclient);
postEntity.addPart("user", cuser);
postEntity.addPart("pwd", cpwd);
postEntity.addPart("type", ctype);
postEntity.addPart("str", cstr);
postEntity.addPart("img", cbFileData);
httpPost.setEntity(postEntity);
// 下面这句话就把数据提交到服务器去了
HttpResponse response = httpClient.execute(httpPost);
// 打开response的数据流，就可以读取服务器端的回执数据
InputStream reader = response.getEntity().getContent();
BufferedReader breader = new BufferedReader(new InputStreamReader(reader));
String readline = null;
String result = "";
while((readline = breader.readLine())!=null)
{
result += readline;
}
System.out.println(result);

} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public String addaction(String para){
String baseurl = base + "/action/AddActivity.action?&client=1";
String allurl = base + "/action/AddActivity.action?&client=1" + para;
return basepost(baseurl, allurl);
}
public String changeComment(String para)
{

String baseUrl = base + "/servlet/ChangeComment?&client=0";

String allurl = base + "/servlet/ChangeComment?&client=0" + para;

return basepost(baseUrl, allurl);
}
public String addfocususer(String para)
{

String baseUrl = base + "/servlet/addfocus?&client=0";

String allurl = base + "/servlet/addfocus?&client=0" + para;

return basepost(baseUrl, allurl);
}
public String search(String para)
{

String baseUrl = base + "/servlet/searchuser?&client=0";

String allurl = base + "/servlet/searchuser?&client=0" + para;

return basepost(baseUrl, allurl);
}
public String register(JSONObject js)
{
String baseUrl = base + "/servlet/register";
String allurl = "";
try {
allurl = base +  "/servlet/?&client=0&jsonuser="+java.net.URLEncoder.encode(js.toString(), "UTF-8");
} catch (UnsupportedEncodingException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}

return basepost(baseUrl, allurl);
}
public String land(String para)
{

String baseUrl = base + "/servlet/login";
String allurl = baseUrl + "/servlet/login?&client=0" + para;

return basepost(baseUrl, allurl);
}
public String getnews(String para)
{
String baseUrl = base + "/servlet/getnews?&client=0";

String strurl = base + "/servlet/getnews?&client=0" + para;

return basepost(baseUrl, strurl);
}
public String sendnews(String text,String para)
{
String baseUrl = base + "/servlet/sendnews?&client=0";
String allurl = "";
try {
allurl = base + "/servlet/sendnews?&client=0" + para + "&text=" + java.net.URLEncoder.encode(text, "UTF-8") ;
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return basepost(baseUrl,allurl);
}
public String basepost(String baseUrl,String allurl){
String result = "";
try {
URL url = new URL(baseUrl);
System.out.println("运行到URL");
try {
HttpURLConnection urlcon = (HttpURLConnection)url.openConnection();
urlcon.setDoInput(true);
urlcon.setDoOutput(true);
urlcon.setRequestMethod("POST");
System.out.println("运行到post");
urlcon.setUseCaches(false);
urlcon.setInstanceFollowRedirects(true);
urlcon.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
urlcon.setRequestProperty("Charset", "UTF-8");
System.out.println("connect");
urlcon.connect();
System.out.println("connect之后");

java.io.DataOutputStream d = new java.io.DataOutputStream(urlcon.getOutputStream());
//	String s = java.net.URLEncoder.encode(strurl, "UTF-8");
d.writeBytes(allurl);
d.flush();
d.close();
BufferedReader buf = new BufferedReader(new InputStreamReader(urlcon.getInputStream(),"UTF-8"));
String readLine = null;
while( (readLine=buf.readLine()) != null){
result += readLine;
}
System.out.println(result);
buf.close();
urlcon.disconnect();

} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();

}

} catch (MalformedURLException e) {
// TODO Auto-generated catch block
System.out.println("连接超时");
e.printStackTrace();
}
return result;
}
}

可能重构的不是很好，最主要的是蓝色部分的basepost（）方法，其他函数只需要把参数传进来就可以了，都是调用basepost