httpclient怎么获取json

package com.example.testjsonandget;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.params.HttpClientParams;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.json.JSONArray;
import org.json.JSONObject;

import android.app.Activity;
import android.os.Bundle;

public class MainActivity extends Activity {

private final String uriString="your url";
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    //服务器返回的JSON数据
    JSONObject jsonObject=this.getJSONObjectByGet();
    try {
        //从JSON中得到字符串
        String apiString=jsonObject.getString("api");
        String countString=jsonObject.getString("count");
        System.out.println("apiString="+apiString+",countString="+countString);
        //从JSON中得到JSONArray,并且遍历
        JSONArray jsonArray=jsonObject.getJSONArray("data");
        for (int i = 0; i < jsonArray.length(); i++) {
            JSONObject everyJsonObject=jsonArray.getJSONObject(i);
            String category_id=everyJsonObject.getString("category_id");
            String category_name=everyJsonObject.getString("category_name");
            String category_rgb=everyJsonObject.getString("category_rgb");
            String category_news_count=everyJsonObject.getString("category_news_count");
            System.out.println("category_id="+category_id+",category_name="+category_name+
            ",category_rgb="+category_rgb+",category_news_count="+category_news_count);
            System.out.println("=====================================================");
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

//得到HttpClient
public HttpClient getHttpClient(){
    HttpParams mHttpParams=new BasicHttpParams();
    //设置网络链接超时
    //即:Set the timeout in milliseconds until a connection is established.
    HttpConnectionParams.setConnectionTimeout(mHttpParams, 20*1000);
    //设置socket响应超时
    //即:in milliseconds which is the timeout for waiting for data.
    HttpConnectionParams.setSoTimeout(mHttpParams, 20*1000);
    //设置socket缓存大小
    HttpConnectionParams.setSocketBufferSize(mHttpParams, 8*1024);
    //设置是否可以重定向
    HttpClientParams.setRedirecting(mHttpParams, true);
    
    HttpClient httpClient=new DefaultHttpClient(mHttpParams);
    return httpClient;
}

//得到JSONObject(Get方式)
public JSONObject getJSONObjectByGet(){
    JSONObject resultJsonObject=null;
    if ("".equals(uriString)||uriString==null) {
        return null;
    }
    HttpClient httpClient=this.getHttpClient();
    StringBuilder urlStringBuilder=new StringBuilder(uriString);
    StringBuilder entityStringBuilder=new StringBuilder();
    //利用URL生成一个HttpGet请求
    HttpGet httpGet=new HttpGet(urlStringBuilder.toString());
    BufferedReader bufferedReader=null;
    HttpResponse httpResponse=null;
    try {
        //HttpClient发出一个HttpGet请求
        httpResponse=httpClient.execute(httpGet);        
    } catch (Exception e) {
        e.printStackTrace();
    }
    //得到httpResponse的状态响应码
    int statusCode=httpResponse.getStatusLine().getStatusCode();
    if (statusCode==HttpStatus.SC_OK) {
        //得到httpResponse的实体数据
        HttpEntity httpEntity=httpResponse.getEntity();
        if (httpEntity!=null) {
            try {
                bufferedReader=new BufferedReader
                (new InputStreamReader(httpEntity.getContent(), "UTF-8"), 8*1024);
                String line=null;
                while ((line=bufferedReader.readLine())!=null) {
                    entityStringBuilder.append(line+"/n");
                }
                //利用从HttpEntity中得到的String生成JsonObject
                resultJsonObject=new JSONObject(entityStringBuilder.toString());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
    return resultJsonObject;
}

//----------------------------------------以下为POST请求
//准备进行POST请求的参数，一般而言将这些参数封装在HashMap中
public JSONObject save(String title, String timelength) throws Exception{
    Map<String,String> paramsHashMap = new HashMap<String, String>();
    paramsHashMap.put("title", title);
    paramsHashMap.put("timelength", timelength);
    paramsHashMap.put("method", "save");
    String path = "your url";
    return getJSONObjectByPost(path, paramsHashMap, "UTF-8");
}
//得到JSONObject(Post方式)
//此方法此处未调用测试
public JSONObject getJSONObjectByPost(String path,Map<String, String> paramsHashMap, String encoding) {
    JSONObject resultJsonObject = null;
    List<NameValuePair> nameValuePairArrayList = new ArrayList<NameValuePair>();
    // 将传过来的参数填充到List<NameValuePair>中
    if (paramsHashMap != null && !paramsHashMap.isEmpty()) {
        for (Map.Entry<String, String> entry : paramsHashMap.entrySet()) {
            nameValuePairArrayList.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
        }
    }
    
    UrlEncodedFormEntity entity = null;
    try {
        // 利用List<NameValuePair>生成Post请求的实体数据
        // 此处使用了UrlEncodedFormEntity!!!
        entity = new UrlEncodedFormEntity(nameValuePairArrayList, encoding);
        HttpPost httpPost = new HttpPost(path);
        // 为HttpPost设置实体数据
        httpPost.setEntity(entity);
        HttpClient httpClient = this.getHttpClient();
        // HttpClient发出Post请求
        HttpResponse httpResponse = httpClient.execute(httpPost);
        if (httpResponse.getStatusLine().getStatusCode() == 200) {
            // 得到httpResponse的实体数据
            HttpEntity httpEntity = httpResponse.getEntity();
            if (httpEntity != null) {
                try {
                    BufferedReader bufferedReader = new BufferedReader(
                    new InputStreamReader(httpEntity.getContent(),"UTF-8"), 8 * 1024);
                    StringBuilder entityStringBuilder = new StringBuilder();
                    String line = null;
                    while ((line = bufferedReader.readLine()) != null) {
                        entityStringBuilder.append(line + "/n");
                    }
                    // 利用从HttpEntity中得到的String生成JsonObject
                    resultJsonObject = new JSONObject(entityStringBuilder.toString());
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return resultJsonObject;
}

}

ps：来源网络