Android Asynchronous Http Client-Android异步网络请求客户端接口

1.简介

Android中网络请求一般使用Apache HTTP Client或者采用HttpURLConnect，但是直接使用这两个类库需要写大量的代码才能完成网络post和get请求，而使用android-async-http这个库可以大大的简化操作，它是基于Apache’s HttpClient ，所有的请求都是独立在UI主线程之外，通过回调方法处理请求结果，采用android Handler message 机制传递信息。

2.特性

(1)采用异步http请求，并通过匿名内部类处理回调结果

(2)http请求独立在UI主线程之外

(3)采用线程池来处理并发请求

(4)采用RequestParams类创建GET/POST参数

(5)不需要第三方包即可支持Multipart file文件上传

(6)大小只有25kb

(7)自动为各种移动电话处理连接断开时请求重连

(8)超快的自动gzip响应解码支持

(9)使用BinaryHttpResponseHandler类下载二进制文件(如图片)

(10) 使用JsonHttpResponseHandler类可以自动将响应结果解析为json格式

(11)持久化cookie存储，可以将cookie保存到你的应用程序的SharedPreferences中

3.使用方法

(1)到官网http://loopj.com/android-async-http/下载最新的android-async-http-1.4.4.jar，然后将此jar包添加进Android应用程序 libs文件夹

(2)通过import com.loopj.android.http.*;引入相关类

(3)创建异步请求

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AsyncHttpClient client = new AsyncHttpClient();client.get("http://www.google.com", new AsyncHttpResponseHandler() {    @Override    public void onSuccess(String response) {        System.out.println(response);    }});

4.建议使用静态的Http Client对象

在下面这个例子，我们创建了静态的http client对象，使其很容易连接到Twitter的API

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import com.loopj.android.http.*;public class TwitterRestClient {  private static final String BASE_URL = "http://api.twitter.com/1/";  private static AsyncHttpClient client = new AsyncHttpClient();  public static void get(String url, RequestParams params, AsyncHttpResponseHandler responseHandler) {      client.get(getAbsoluteUrl(url), params, responseHandler);  }  public static void post(String url, RequestParams params, AsyncHttpResponseHandler responseHandler) {      client.post(getAbsoluteUrl(url), params, responseHandler);  }  private static String getAbsoluteUrl(String relativeUrl) {      return BASE_URL + relativeUrl;  }}

然后我们可以很容易的在代码中操作Twitter的API

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import org.json.*;import com.loopj.android.http.*;class TwitterRestClientUsage {    public void getPublicTimeline() throws JSONException {        TwitterRestClient.get("statuses/public_timeline.json", null, new JsonHttpResponseHandler() {            @Override            public void onSuccess(JSONArray timeline) {                // Pull out the first event on the public timeline                JSONObject firstEvent = timeline.get(0);                String tweetText = firstEvent.getString("text");                // Do something with the response                System.out.println(tweetText);            }        });    }}

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5. AsyncHttpClient, RequestParams ,AsyncHttpResponseHandler三个类使用方法**

(1)AsyncHttpClient

public class AsyncHttpClient extends java.lang.Object

该类通常用在android应用程序中创建异步GET, POST, PUT和DELETE HTTP请求，请求参数通过RequestParams实例创建，响应通过重写匿名内部类 ResponseHandlerInterface的方法处理。

例子：

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AsyncHttpClient client = new AsyncHttpClient(); client.get("http://www.google.com", new ResponseHandlerInterface() {     @Override     public void onSuccess(String response) {         System.out.println(response);     } });

(2)RequestParams

public class RequestParams extends java.lang.Object

用于创建AsyncHttpClient实例中的请求参数(包括字符串或者文件)的集合

例子：

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RequestParams params = new RequestParams(); params.put("username", "james"); params.put("password", "123456"); params.put("email", "[e-mail]"); params.put("profile_picture", new File("pic.jpg")); // Upload a File params.put("profile_picture2", someInputStream); // Upload an InputStream params.put("profile_picture3", new ByteArrayInputStream(someBytes)); // Upload some bytes Map<String, String> map = new HashMap<String, String>(); map.put("first_name", "James"); map.put("last_name", "Smith"); params.put("user", map); // url params: "user[first_name]=James&user[last_name]=Smith" Set<String> set = new HashSet<String>(); // unordered collection set.add("music"); set.add("art"); params.put("like", set); // url params: "like=music&like=art" List<String> list = new ArrayList<String>(); // Ordered collection list.add("Java"); list.add("C"); params.put("languages", list); // url params: "languages[]=Java&languages[]=C" String[] colors = { "blue", "yellow" }; // Ordered collection params.put("colors", colors); // url params: "colors[]=blue&colors[]=yellow" List<Map<String, String>> listOfMaps = new ArrayList<Map<String, String>>(); Map<String, String> user1 = new HashMap<String, String>(); user1.put("age", "30"); user1.put("gender", "male"); Map<String, String> user2 = new HashMap<String, String>(); user2.put("age", "25"); user2.put("gender", "female"); listOfMaps.add(user1); listOfMaps.add(user2); params.put("users", listOfMaps); // url params: "users[][age]=30&users[][gender]=male&users[][age]=25&users[][gender]=female" AsyncHttpClient client = new AsyncHttpClient(); client.post("http://myendpoint.com", params, responseHandler);

(3)public class AsyncHttpResponseHandler extends java.lang.Object implements ResponseHandlerInterface

用于拦截和处理由AsyncHttpClient创建的请求。在匿名类AsyncHttpResponseHandler中的重写 onSuccess(int, org.apache.http.Header[], byte[])方法用于处理响应成功的请求。此外，你也可以重写 onFailure(int, org.apache.http.Header[], byte[], Throwable), onStart(), onFinish(), onRetry() 和onProgress(int, int)方法

例子：

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AsyncHttpClient client = new AsyncHttpClient(); client.get("http://www.google.com", new AsyncHttpResponseHandler() {     @Override     public void onStart() {         // Initiated the request     }     @Override     public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) {         // Successfully got a response     }     @Override     public void onFailure(int statusCode, Header[] headers, byte[] responseBody, Throwable error) {         // Response failed :(     }     @Override     public void onRetry() {         // Request was retried     }     @Override     public void onProgress(int bytesWritten, int totalSize) {         // Progress notification     }     @Override     public void onFinish() {         // Completed the request (either success or failure)     } });

6.利用PersistentCookieStore持久化存储cookie

PersistentCookieStore类用于实现Apache HttpClient的CookieStore接口，可以自动的将cookie保存到Android设备的SharedPreferences中，如果你打算使用cookie来管理验证会话，这个非常有用，因为用户可以保持登录状态，不管关闭还是重新打开你的app

(1)首先创建 AsyncHttpClient实例对象

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AsyncHttpClient myClient = new AsyncHttpClient();

(2)将客户端的cookie保存到PersistentCookieStore实例对象,带有activity或者应用程序context的构造方法

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PersistentCookieStore myCookieStore = new PersistentCookieStore(this);myClient.setCookieStore(myCookieStore);

(3)任何从服务器端获取的cookie都会持久化存储到myCookieStore中，添加一个cookie到存储中，只需要构造一个新的cookie对象，并且调用addCookie方法

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BasicClientCookie newCookie = new BasicClientCookie("cookiesare", "awesome");newCookie.setVersion(1);newCookie.setDomain("mydomain.com");newCookie.setPath("/");myCookieStore.addCookie(newCookie);

7.利用RequestParams上传文件

类RequestParams支持multipart file 文件上传

(1)在RequestParams 对象中添加InputStream用于上传

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InputStream myInputStream = blah;RequestParams params = new RequestParams();params.put("secret_passwords", myInputStream, "passwords.txt");

(2)添加文件对象用于上传

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File myFile = new File("/path/to/file.png");RequestParams params = new RequestParams();try {    params.put("profile_picture", myFile);} catch(FileNotFoundException e) {}

(3)添加字节数组用于上传

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byte[] myByteArray = blah;RequestParams params = new RequestParams();params.put("soundtrack", new ByteArrayInputStream(myByteArray), "she-wolf.mp3");

8.用BinaryHttpResponseHandler下载二进制数据

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BinaryHttpResponseHandler用于获取二进制数据如图片和其他文件AsyncHttpClient client = new AsyncHttpClient();String[] allowedContentTypes = new String[] { "image/png", "image/jpeg" };client.get("http://example.com/file.png", new BinaryHttpResponseHandler(allowedContentTypes) {    @Override    public void onSuccess(byte[] fileData) {        // Do something with the file    }});

使用实例：package com.example.login;


import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.AsyncHttpResponseHandler;
import com.loopj.android.http.RequestParams;

public class AsynchronousHttpClient extends Activity {

private EditText userName;
private EditText userPwd;
private Button btn1;
private Button btn2;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
userName = (EditText) findViewById(R.id.et1);// 用户名
userPwd = (EditText) findViewById(R.id.et2);// 密码

btn1 = (Button) findViewById(R.id.btn1);// 登录
btn2 = (Button) findViewById(R.id.btn2);
this.btn1.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String name = userName.getText().toString();
String password = userPwd.getText().toString();

AsyncHttpClient client = new AsyncHttpClient();
/* String url = "http://www.baidu.com"; */

String url = "http://"
+ "192.168.0.100:8080/Mall/SysLoginAndRegisterAction_androidCheckLogin";//此处为要请求的URL
RequestParams params = new RequestParams();
params.add("loginId", name);
params.add("userPsw", password);
client.get(url, params, new AsyncHttpResponseHandler() {//注意传参与否


@Override
public void onSuccess(String response) {
Toast.makeText(AsynchronousHttpClient.this,
"ndasaahas", 3000).show();
System.out.println(response);
}

});


}
});
}


}

注：在layout布局时，简单弄EditText，分别为填写用户名和密码，和按钮（登录，注册）便可以测试。

对于以上内容，可以参考资料：http://loopj.com/android-async-http/