请求服务器图片并显示

1.客户端

package com.jingle.requestimg;

import org.apache.http.Header;

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

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;

public class MainActivity extends Activity {
    private String url = "http://192.168.1.101:8080/Login/servlet/ReturnImg";

    private ImageView imageView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initImgView();
        initBtn();
    }

    private void initImgView() {
        imageView = (ImageView) findViewById(R.id.img);
    }

    private void initBtn() {
        Button btn = (Button) findViewById(R.id.btn);
        btn.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                getServerImg();

            }
        });
    }

    private void getServerImg() {
        AsyncHttpClient client = new AsyncHttpClient();
        client.setTimeout(3000);
        RequestParams params = new RequestParams();
        params.put("img", "img");
        client.post(url, params, new AsyncHttpResponseHandler() {

            @Override
            public void onSuccess(int statusCode, Header[] headers,
                    byte[] responseBody) {
                if (responseBody != null) {
                    Bitmap bmp = BitmapFactory.decodeByteArray(responseBody, 0,
                            responseBody.length);
                    imageView.setImageBitmap(bmp);
                }
            }

            public void onFailure(int statusCode, Header[] headers,
                    byte[] responseBody, Throwable error) {
                error.printStackTrace();
            }
        });
    }

}

2.服务器端

package action;

import java.io.FileInputStream;
import java.io.IOException;

import java.io.OutputStream;

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

public class ReturnImg extends HttpServlet {

    private static final long serialVersionUID = -70601451108821183L;
    private static final String JPG = "image/jpeg;charset=GB2312";

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        doPost(request, response);
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        System.out.println("do post");
        String webRootUrl = request.getServletContext().getRealPath("")
                + "//guan.jpg";
        if ("img".equals(request.getParameter("img"))) {

            FileInputStream fis = new FileInputStream(webRootUrl);
            int size = fis.available();
            byte[] data = new byte[size];
            fis.read(data);
            fis.close();
            response.setContentType(JPG);
            OutputStream os = response.getOutputStream();
            os.write(data);
            os.flush();
            os.close();

        }

    }

}