JAVA_Gson_example

 package cn.kjxy.GSON;

 import java.util.List;

 import cn.kjxy.JSON.HttpHelpers;

 import com.google.gson.Gson;

 /**
  * gson解析json对象 ：
  * 注意：1.建立的属性或者对象名必须与json数据中的一致才能解析出来
  *         2。需导入gson-2.2.1.jar包
  *         工具类需导入：commons-logging-1.1.1.jar
  *                 httpclient-4.1.2.jar
  *                 httpcore-4.1.2.jar
  *
  * @author Administrator
  *
  */
 class Food {
     private int ret;
     private List<Data> data;

     @Override
     public String toString() {
         return "Food [ret=" + ret + ", data=" + data + "]";
     }

 }

 class Data {

     private int id;// ": "8289",
     private String title;// ": "油焖大虾",
     private String pic;// ": "http://www.qubaobei.com/ios/cf/uploadfile/132/9/8289.jpg",
     private int collect_num;// ": "1544",
     private String food_str;// ": "大虾 葱 生姜 植物油 料酒",
     private int num;// ": 1544

     @Override
     public String toString() {
         return "Data [id=" + id + ", title=" + title + ", pic=" + pic
                 + ", collect_num=" + collect_num + ", food_str=" + food_str
                 + ", num=" + num + "]";
     }

 }

 public class Demo2 {
     public static void main(String[] args) {
         // gson解析json对象
         String json1 = HttpHelpers
                 .getResourceByInternet("http://www.qubaobei.com/ios/cf/dish_list.php?stage_id=1&page=1&limit=20");
         parserJsonByGson(json1);
     }

     private static void parserJsonByGson(String json1) {
         // TODO Auto-generated method stub
         Gson gson = new Gson();
         Food food = gson.fromJson(json1, Food.class);
         System.out.println(food);
     }

 }

工具类：

 package cn.kjxy.JSON;

 import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
 import java.io.BufferedReader;
 import java.io.ByteArrayOutputStream;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 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.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.impl.client.DefaultHttpClient;
 import org.apache.http.message.BasicNameValuePair;
 import org.apache.http.util.EntityUtils;

 /**
  * 请求网络的工具类
  *
  * @author Administrator
  *
  */
 public class HttpHelpers {

     /**
      * 下载图片 保存到byte类型的数组中
      *
      * @param path
      *            地址
      * @return byte[]
      */
     public static byte[] downLoadImg(String path) {
         BufferedInputStream bis = null;
         try {
             // 1,创建HttpClient对象 Android6.0之前可以使用
             HttpClient httpClient = new DefaultHttpClient();
             // 2,创建请求对象+指定地址
             HttpGet httpGet = new HttpGet(path);
             // 3,执行请求 获得HttpResponse对象
             HttpResponse response = httpClient.execute(httpGet);
             // 4,获得响应码
             int code = response.getStatusLine().getStatusCode();
             if (code == 200) {
                 // 5,得到响应的HttpEntity对象
                 HttpEntity responseEntity = response.getEntity();
                 // 方法一
                 // bis = new BufferedInputStream(responseEntity.getContent());
                 // byte b[] = toByteArray(bis);
                 // return b;

                 // 方法二
                 return EntityUtils.toByteArray(responseEntity);

             }

         } catch (IOException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         } finally {
             if (bis != null) {
                 try {
                     bis.close();
                 } catch (IOException e) {
                     // TODO Auto-generated catch block
                     e.printStackTrace();
                 }
             }
         }

         return null;

     }

     /**
      * 把图片下载到本地磁盘
      *
      * @param path
      */
     public static void downLoadImgToLocal(String path) {
         BufferedInputStream bis = null;
         BufferedOutputStream boStream = null;
         try {
             // 1,创建HttpClient对象 Android6.0之前可以使用
             HttpClient httpClient = new DefaultHttpClient();
             // 2,创建请求对象+指定地址
             HttpGet httpGet = new HttpGet(path);
             // 3,执行请求 获得HttpResponse对象
             HttpResponse response = httpClient.execute(httpGet);
             // 4,获得响应码
             int code = response.getStatusLine().getStatusCode();
             if (code == 200) {
                 // 5,得到响应的HttpEntity对象
                 HttpEntity responseEntity = response.getEntity();
                 // 方法一
                 // bis = new BufferedInputStream(responseEntity.getContent());
                 // byte b[] = toByteArray(bis);

                 // 方法二
                 byte b[] = EntityUtils.toByteArray(responseEntity);
                 String endsWith = path.substring(path.lastIndexOf("."));
                 boStream = new BufferedOutputStream(new FileOutputStream(
                         (int) (Math.random() * 100) + endsWith));
                 boStream.write(b);

             }

         } catch (IOException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         } finally {
             if (bis != null) {
                 try {
                     bis.close();
                 } catch (IOException e) {
                     // TODO Auto-generated catch block
                     e.printStackTrace();
                 }
             }
             if (boStream != null) {
                 try {
                     boStream.close();
                 } catch (IOException e) {
                     // TODO Auto-generated catch block
                     e.printStackTrace();
                 }
             }
         }

     }

     /**
      * 从互联网获取文本 json xml
      *
      * @param path
      *            地址
      * @return 获取到的文本数据
      */

     public static String getResourceByInternet(String path) {
         BufferedReader bReader = null;
         try {
             // 1,创建HttpClient对象 Android6.0之前可以使用
             HttpClient httpClient = new DefaultHttpClient();
             // 2,创建请求对象+指定地址
             HttpGet httpGet = new HttpGet(path);
             // 3,执行请求 获得HttpResponse对象
             HttpResponse response = httpClient.execute(httpGet);
             // 4,获得响应码
             int code = response.getStatusLine().getStatusCode();
             if (code == 200) {
                 // 得到HttpEntity对象
                 HttpEntity responseEntity = response.getEntity();
                 // 方法一
                 // bReader = new BufferedReader(new
                 // InputStreamReader(responseEntity.getContent()));
                 // StringBuilder sbBuilder = new StringBuilder();
                 // String line = null;
                 // while ((line = bReader.readLine()) != null) {
                 // sbBuilder.append(line);
                 // }
                 //
                 // return sbBuilder.toString();

                 // 方法二
                 return EntityUtils.toString(responseEntity);

             }

         } catch (IOException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         } finally {
             if (bReader != null) {
                 try {
                     bReader.close();
                 } catch (IOException e) {
                     // TODO Auto-generated catch block
                     e.printStackTrace();
                 }
             }
         }

         return null;

     }

     public static byte[] toByteArray(BufferedInputStream bufferedInputStream) {
         byte b[] = new byte[1024 * 1024];
         int len = 0;
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
         try {
             while ((len = bufferedInputStream.read(b)) != -1) {
                 baos.write(b, 0, len);
             }
         } catch (IOException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }

         return baos.toByteArray();

     }

     public static String upLoadData(String path, Map<String, String> map) {
         BufferedReader bReader = null;
         try {
             // 1,创建HttpClient对象 Android6.0之前可以使用
             HttpClient httpClient = new DefaultHttpClient();
             // 2,创建请求对象+指定地址
             HttpPost httpPost = new HttpPost(path);
             // 设置用于发送到服务端的参数
             List<NameValuePair> list = new ArrayList<NameValuePair>();

             for (String string : map.keySet()) {
                 list.add(new BasicNameValuePair(string, map.get(string)));
             }
             HttpEntity requestEntity = new UrlEncodedFormEntity(list, "gbk");
             httpPost.setEntity(requestEntity);

             // 3,执行请求 获得HttpResponse对象
             HttpResponse response = httpClient.execute(httpPost);
             // 4,获得响应码
             int code = response.getStatusLine().getStatusCode();
             if (code == 200) {
                 // 得到HttpEntity对象
                 HttpEntity responseEntity = response.getEntity();
                 // 方法一
                 // bReader = new BufferedReader(new
                 // InputStreamReader(responseEntity.getContent()));
                 // StringBuilder sbBuilder = new StringBuilder();
                 // String line = null;
                 // while ((line = bReader.readLine()) != null) {
                 // sbBuilder.append(line);
                 // }
                 //
                 // return sbBuilder.toString();

                 // 方法二
                 return EntityUtils.toString(responseEntity, "gbk");

             }

         } catch (IOException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         } finally {
             if (bReader != null) {
                 try {
                     bReader.close();
                 } catch (IOException e) {
                     // TODO Auto-generated catch block
                     e.printStackTrace();
                 }
             }
         }

         return null;

     }

     public static void main(String[] args) {
         byte b[] = downLoadImg("http://images.china.cn/attachement/jpg/site1000/20140313/844bf52c7d7c148b8abc05.jpg");
         BufferedOutputStream bufferedOutputStream;
         try {
             bufferedOutputStream = new BufferedOutputStream(
                     new FileOutputStream("ceo.jpg"));
             // bufferedOutputStream.write(b);

         } catch (FileNotFoundException e1) {
             // TODO Auto-generated catch block
             e1.printStackTrace();
         } catch (IOException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }

         // downLoadImgToLocal("http://images.china.cn/attachement/jpg/site1000/20140313/844bf52c7d7c148b8abc05.jpg");

         // System.out.println(getResourceByInternet("http://www.doukantv.com/api/hot/?type=movie&cli=ipad&sys_ver=7.1.1&ver=2.1"));
         Map<String, String> map = new HashMap<String, String>();
         map.put("uname", "张三");
         map.put("pwd", "admin");
         System.out.println(upLoadData(
                 "http://172.20.136.5:8080/2016_05_27_server/login", map));

     }

 }