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异步http提交数据到服务器

2013-11-01 15:46 288 查看

1.Android操作UI的方法不是线程安全的，开发者自己生成的线程对象是不能直接操作UI的，比如在新线程里修改某个TextView，生成某个Toast。

异步AsyncHttpClient封装了httpclient，用起来比较方便

下面就例子来实践一下怎么用异步http框架和简单地仿写异步http框架

1.AndroidManifest.xml添加网络访问权限

<uses-permission android:name="android.permission.INTERNET"/>

2.在web项目中新建servlet，部署到服务器上

package cn.com.servlet;

import java.io.IOException;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class LoginServlet extends HttpServlet {

	@Override
	protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		// 服务器接受统一编码iso-8859-1,然后获取字符串时转化为utf-8
		String name = new String(request.getParameter("name").getBytes(
				"iso-8859-1"), "utf-8");
		String password = request.getParameter("password");
		System.out.println("name:" + name);
		System.out.println("password:" + password);
		if (name.equals("张三") && password.equals("123")) {
			// 往浏览器写字符串
			response.getOutputStream().write(
					"HttpClienget方式登录成功".getBytes("utf-8")); // 写到浏览器的编码是utf-8
		} else {
			response.getOutputStream().write(
					"HttpClienget方式登录失败".getBytes("utf-8")); // 写到浏览器的编码是utf-8
		}
	}

	@Override
	protected void doPost(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		// doGet(request, response);
		// 服务器接受统一编码iso-8859-1,然后获取字符串时转化为utf-8
		String name = new String(request.getParameter("name").getBytes(
				"iso-8859-1"), "utf-8");
		String password = request.getParameter("password");
		System.out.println("name:" + name);
		System.out.println("password:" + password);
		if (name.equals("张三") && password.equals("123")) {
			// 往浏览器写字符串
			response.getOutputStream().write(
					"HttpClienpost方式登录成功".getBytes("utf-8")); // 写到浏览器的编码是utf-8
		} else {
			response.getOutputStream().write(
					"HttpClientpost方式登录失败".getBytes("utf-8")); // 写到浏览器的编码是utf-8
		}
	}

}

3.文件布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
 
    <EditText
        android:id="@+id/name"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:hint="输入用户名" 
        android:text="张三"
        />
    <EditText
        android:id="@+id/password"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:hint="输入密码" />
   
   
     <Button
        android:id="@+id/button"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="异步提交get方式提交"
        android:onClick="onClick1"
         />
    
     <Button
        android:id="@+id/button"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="异步提交post方式提交"
        android:onClick="onClick2"
         />
</LinearLayout>

4.要想使用异步http框架，首先要下载已经封装好的源代码

下载地址：https://github.com/search?p=2&q=android&ref=cmdform&type=Repositories

loopj/android-async-http

下载这个开源代码。下载解压后，里面有例子可参考。把src目录下地包复制项目src中，这样就可以使用里面的做好的异步http框架了。

MainActivity.java

package com.example.get;

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;

import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.AsyncHttpResponseHandler;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {
	private EditText name,password;
	private final int SUCCESS=1;
	
	private Handler handler = new Handler(){

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        name = (EditText) findViewById(R.id.name);
        password = (EditText) findViewById(R.id.password);
        
      
    }

   //get方法请求
   public void onClick1(View view){
	   final String loginName = name.getText().toString();
	   final String loginPasswor = password.getText().toString();
	   
	   //实例化异步http类
	   AsyncHttpClient client = new AsyncHttpClient();
	   
	   String path = "http://10.162.0.171:8080/WebGet/LoginServlet?name="+URLEncoder.encode(loginName)+"&password="+URLEncoder.encode(loginPasswor);
       //调用get方法，调用做好的AsyncHttpResponseHandler消息处理器，更新ui
	   client.get(path, new AsyncHttpResponseHandler(){

		@Override
		public void onSuccess(String content) {
			Toast.makeText(MainActivity.this, content, 1).show();
		}

		@Override
		public void onFailure(int statusCode, Throwable error, String content) {
			// TODO Auto-generated method stub
			super.onFailure(statusCode, error, content);
			Toast.makeText(MainActivity.this,content, 1).show();
		}
		   
	   } );
	   
   }
//post方法请求
 public void onClick2(View view){
	   final String loginName = name.getText().toString();
	   final String loginPassword = password.getText().toString();
	   
	   
	   AsyncHttpClient client = new AsyncHttpClient();
	   
		String postpath = "http://10.162.0.171:8080/WebGet/LoginServlet";
		//设置参数
		 RequestParams params = new RequestParams();
		 params.put("name", loginName);
		 params.put("password", loginPassword);
		 client.post(postpath, params, new AsyncHttpResponseHandler(){

			@Override
			public void onSuccess(String content) {
				// TODO Auto-generated method stub
				super.onSuccess(content);
				Toast.makeText(MainActivity.this, "发送请求:"+content, 1).show();
			}

			@Override
			public void onFailure(Throwable error, String content) {
				// TODO Auto-generated method stub
				super.onFailure(error, content);
				Toast.makeText(MainActivity.this, "发送请求:"+content, 1).show();
			}
			
		});
   }
    
}

Post方法请求设置参数是，点进去可见到有丰富的各种参数类型

简单的几步就完成了，乱码问题都已经帮我们解决了。

运行结果

到底异步http框架是如何封装httpclient的呢？下面我们通过一个简单的仿写http框架例子来理解它（这里仿写只是get方式提交）

1.这里是访问上面部署好的web，也用上面的布局文件。（这里就不在重复写了）

(1)

MainActivity.java

package com.example.asnychttp;

import java.net.URLEncoder;

import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {
	private EditText name, password;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		name = (EditText) findViewById(R.id.name);
		password = (EditText) findViewById(R.id.password);
	}

	public void onClick(View view) {
		String loginName = name.getText().toString();
		String loginPwd = password.getText().toString();
		// 1 开启子线程，执行一个http请求【在后台执行，在子线程执行】
		// 2.子线程执行完毕后，通知ui，更新页面
		// AsyncHttpClient类，我们自己写出来
		AsyncHttpClient client = new AsyncHttpClient();
		// 输入地址
		String path = "http://10.162.0.171:8080/WebGet/LoginServlet?name="
				+ URLEncoder.encode(loginName) + "&password="
				+ URLEncoder.encode(loginPwd);

		// 我们自定义一个MyHandler消息处理器来更改ui
		client.get(path, new MyHandler() {

			@Override
			public void onSuccess(String content) {
				// TODO Auto-generated method stub
				super.onSuccess(content);
				Toast.makeText(MainActivity.this, "发出请求：" + content, 2).show();
			}

			@Override
			public void onFailure(String content) {
				// TODO Auto-generated method stub
				super.onFailure(content);
				Toast.makeText(MainActivity.this, "发出请求：" + content, 2).show();
			}
		});
	}

}

(2)

AsyncHttpClient.java

package com.example.asnychttp;

import java.io.IOException;
import java.io.InputStream;

import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

import android.os.Message;

/**
 * 异步http类
 * 
 * @author lenovo
 * 
 */
public class AsyncHttpClient {
	private final int SUCCESS = 1;
	private final int ERROR = 2;

	public void get(final String path, final MyHandler myHandler) {
		new Thread() {
			public void run() {
				// 打开浏览器
				HttpClient httpClient = new DefaultHttpClient();
				// 输入地址
				HttpGet httpGet = new HttpGet(path);
				// 敲回车
				try {
					HttpResponse httpResponse = httpClient.execute(httpGet);
					InputStream is = httpResponse.getEntity().getContent();
					String content = StreamTools.readInputStream(is);
					// 执行成功,发送消息
					Message msg = new Message();
					msg.what = SUCCESS;
					msg.obj = content;
					myHandler.sendMessage(msg);
				} catch (IOException e) {
					// 执行失败，发送消息
					Message msg = new Message();
					msg.what = ERROR;
					msg.obj = "请求失败";
					myHandler.sendMessage(msg);
					e.printStackTrace();
				}
			}
		}.start();
	}

}

（3）消息处理器类

MyHandler.java

package com.example.asnychttp;
 
import android.os.Handler;
import android.os.Message;
 
/**
 * 自定义主线程消息处理器
 * @author lenovo
 *
 */
public class MyHandler extends Handler{
//成功执行的方法
public void onSuccess(String content){
}
//失败执行的方法
public void onFailure(String content){
}
 
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
String content = (String) msg.obj;
switch(msg.what){
case 1:
onSuccess(content);
break;
case 2:
onFailure(content);
break;
}
}
 
}
 
 
(4)读流工具类
 
StreamTools.java
package com.example.asnychttp;
 
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
 
public class StreamTools {
 
	/**
	 * 读取流
	 * @param is
	 * @return
	 */
	public static String readInputStream(InputStream is) {
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		byte[] buffer = new byte[1024];
		int len =0;
		try {
			if((len=is.read(buffer))!=-1){
				baos.write(buffer, 0, len);
			}
			byte[] b = baos.toByteArray();
			return new String(b);
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return null;
		}
	}
	 
}

这就是一个简单的仿异步http框架

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