JSON 之JAVA 解析

一、   JSON (JavaScript Object Notation)一种简单的数据格式,比xml更轻巧。
 Json建构于两种结构:
     1、“名称/值”对的集合(A collection of name/value pairs)。不同的语言中,它被理解为对象(object),纪录(record),结构(struct),字典(dictionary),哈希表(hash table),有键列表(keyed list),或者关联数组 (associative array)。 如:     
        {
            “name”:”jackson”,
            “age”:100
         }

2、值的有序列表(An ordered list of values)。在大部分语言中,它被理解为数组(array)如:
     {
        “students”:
        [
            {“name”:”jackson”,“age”:100},
            {“name”:”michael”,”age”:51}
        ]
     }
二、java解析JSON步骤
    A、服务器端将数据转换成json字符串
      首先、服务器端项目要导入json的jar包和json所依赖的jar包至builtPath路径下(这些可以到JSON-lib官网下载:http://json-lib.sourceforge.net/
 JSON 之JAVA 解析
 
    然后将数据转为json字符串,核心函数是:
 public static String createJsonString(String key, Object value)
    {
        JSONObject jsonObject = new JSONObject();
        jsonObject.put(key, value);
        return jsonObject.toString();
    }
B、客户端将json字符串转换为相应的javaBean
   1、客户端获取json字符串(因为android项目中已经集成了json的jar包所以这里无需导入)
public class HttpUtil
{
   
    public static String getJsonContent(String urlStr)
    {
        try
        {// 获取HttpURLConnection连接对象
            URL url = new URL(urlStr);
            HttpURLConnection httpConn = (HttpURLConnection) url
                    .openConnection();
            // 设置连接属性
            httpConn.setConnectTimeout(3000);
            httpConn.setDoInput(true);
            httpConn.setRequestMethod("GET");
            // 获取相应码
            int respCode = httpConn.getResponseCode();
            if (respCode == 200)
            {
                return ConvertStream2Json(httpConn.getInputStream());
            }
        }
        catch (MalformedURLException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        catch (IOException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return "";
    }

private static String ConvertStream2Json(InputStream inputStream)
    {
        String jsonStr = "";
        // ByteArrayOutputStream相当于内存输出流
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len = 0;
        // 将输入流转移到内存输出流中
        try
        {
            while ((len = inputStream.read(buffer, 0, buffer.length)) != -1)
            {
                out.write(buffer, 0, len);
            }
            // 将内存流转换为字符串
            jsonStr = new String(out.toByteArray());
        }
        catch (IOException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return jsonStr;
    }
}
2、获取javaBean
    public static Person getPerson(String jsonStr)
    {
        Person person = new Person();
        try
        {// 将json字符串转换为json对象
            JSONObject jsonObj = new JSONObject(jsonStr);
            // 得到指定json key对象的value对象
            JSONObject personObj = jsonObj.getJSONObject("person");
            // 获取之对象的所有属性
            person.setId(personObj.getInt("id"));
            person.setName(personObj.getString("name"));
            person.setAddress(personObj.getString("address"));
        }
        catch (JSONException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

return person;
    }

public static List<Person> getPersons(String jsonStr)
    {
        List<Person> list = new ArrayList<Person>();

JSONObject jsonObj;
        try
        {// 将json字符串转换为json对象
            jsonObj = new JSONObject(jsonStr);
            // 得到指定json key对象的value对象
            JSONArray personList = jsonObj.getJSONArray("persons");
            // 遍历jsonArray
            for (int i = 0; i < personList.length(); i++)
            {
                // 获取每一个json对象
                JSONObject jsonItem = personList.getJSONObject(i);
                // 获取每一个json对象的值
                Person person = new Person();
                person.setId(jsonItem.getInt("id"));
                person.setName(jsonItem.getString("name"));
                person.setAddress(jsonItem.getString("address"));
                list.add(person);
            }
        }
        catch (JSONException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

return list;
    }

上一篇:MVC控制器方法返回类型


下一篇:在c#中使用graphics.drawimage方法