json格式解析的全過程

package com.zml.pojo;

/**
 * @author 鄭明亮
 * @Time：2016年2月2日 下午10:35:05
 * @version 1.0
 */
public class Person {

    String name;
    String sex;
    String QQ;
    String contact;

    public Person() {
        // TODO Auto-generated constructor stub
    }

    public Person(String name, String sex, String qQ, String contact) {
        super();
        this.name = name;
        this.sex = sex;
        QQ = qQ;
        this.contact = contact;
    }

    /**
     * @return the name
     */
    public String getName() {
        return name;
    }

    /**
     * @param name
     *            the name to set
     */
    public void setName(String name) {
        this.name = name;
    }

    /**
     * @return the sex
     */
    public String getSex() {
        return sex;
    }

    /**
     * @param sex
     *            the sex to set
     */
    public void setSex(String sex) {
        this.sex = sex;
    }

    /**
     * @return the qQ
     */
    public String getQQ() {
        return QQ;
    }

    /**
     * @param qQ
     *            the qQ to set
     */
    public void setQQ(String qQ) {
        QQ = qQ;
    }

    /**
     * @return the contact
     */
    public String getContact() {
        return contact;
    }

    /**
     * @param contact
     *            the contact to set
     */
    public void setContact(String contact) {
        this.contact = contact;
    }

    /*
     * (non-Javadoc)
     *
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString() {
        return "Person [name=" + name + ", sex=" + sex + ", QQ=" + QQ
                + ", contact=" + contact + "]";
    }

}

 

2.我寫了一個工具類，用來生成上述的四種類型的數據；

package com.zml.utils;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.zml.pojo.Person;

/**
 * 用於生成四種類型的數據來測試json解析：
 * ①Person對象類型 ②List<Person> ③List<String> ④List<Map<String,Object>>
 *
 * @author 鄭明亮
 * @Time：2016年2月2日 下午10:38:40
 * @version 1.0
 */
public class DataUtil {

    public static Person getPerson() {

        return new Person("鄭明亮", "男", "1072307340", "15733100573");
    }

    public static List<Person> getPersons() {
        List<Person> list = new ArrayList<Person>();
        list.add(getPerson());
        list.add(new Person("張三", "男", "123456789", "98765432"));
        list.add(new Person("李四", "女", "762348234", "12312124324"));
        return list;

    }

    public static List<String>    getStrings(){
        List<String>list = new ArrayList<String>();
        list.add("鄭明亮");
        list.add("張三");
        list.add("李四");

        return list;
    }

    public static List<Map<String,Object>> getMaps(){

        List<Map<String,Object>> list = new ArrayList<Map<String,Object>>();
        Map<String,Object> map = new HashMap<String, Object>();
        map.put("name","鄭明亮" );
        map.put("blog", "blog.csdn.net/zml_2015");
        map.put("person", getPerson());
        list.add(map);
        return list;

    }

}

3.接下來就是寫json數據類型的轉換類了

package com.zml.utils;

import net.sf.json.JSONObject;

/**
 * @author 鄭明亮
 * @Time：2016年2月2日 上午12:18:38
 * @version 1.0
 */
public class JsonTools {


    public static String  createJsonString(String key,Object value){

        JSONObject jsonObject=new JSONObject();
        jsonObject.put(key, value);
        return jsonObject.toString();

        }

}

 

4.進行測試，看是否將上述4種數據轉換爲了json的數據類型

 

package com.zml.test;

import com.zml.utils.DataUtil;
import com.zml.utils.JsonTools;

/**
 * @author 鄭明亮
 * @Time：2016年2月2日 上午12:27:29
 * @version 1.0
 */
public class testjson {

    public static void main(String[] args) {
            String jsonString;
            jsonString = JsonTools.createJsonString("person",DataUtil.getPerson());

            System.out.println(jsonString);
            jsonString = JsonTools.createJsonString("persons",DataUtil.getPersons());

            System.out.println(jsonString);
            jsonString = JsonTools.createJsonString("strings",DataUtil.getStrings());

            System.out.println(jsonString);
            jsonString = JsonTools.createJsonString("maps",DataUtil.getMaps());
            System.out.println(jsonString);
        }



}

5.測試成功後，建立Servlet類，以方便將json數據傳輸給客戶端

<p>package com.zml.test;</p><p>import java.io.IOException;
import java.io.PrintWriter;</p><p>import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;</p><p>import com.zml.utils.DataUtil;
import com.zml.utils.JsonTools;</p><p>/**
 * @author 鄭明亮
 * @Time：2016年2月2日 下午10:54:26
 * @version 1.0
 */
public class JsonServlet extends HttpServlet {</p><p> /**
  * Constructor of the object.
  */
 public JsonServlet() {
  super();
 }</p><p> /**
  * Destruction of the servlet. <br>
  */
 public void destroy() {
  super.destroy(); // Just puts "destroy" string in log
  // Put your code here
 }</p><p> /**
  * The doGet method of the servlet. <br>
  *
  * This method is called when a form has its tag value method equals to get.
  *
  * @param request
  *            the request send by the client to the server
  * @param response
  *            the response send by the server to the client
  * @throws ServletException
  *             if an error occurred
  * @throws IOException
  *             if an error occurred
  */
 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
  this.doPost(request, response);</p><p> }</p><p> /**
  * The doPost method of the servlet. <br>
  *
  * This method is called when a form has its tag value method equals to
  * post.
  *
  * @param request
  *            the request send by the client to the server
  * @param response
  *            the response send by the server to the client
  * @throws ServletException
  *             if an error occurred
  * @throws IOException
  *             if an error occurred
  */
 public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {</p><p>  response.setContentType("text/html;charset=utf-8");
  request.setCharacterEncoding("utf-8");
  response.setCharacterEncoding("utf-8");
  PrintWriter out = response.getWriter();</p><p>  String jsonString="";
  String  actionString = request.getParameter("action");

  if (actionString.equals("person")) {

   jsonString = JsonTools.createJsonString("person",DataUtil.getPerson());</p><p>  } else if (actionString.equals("persons")) {

   jsonString = JsonTools.createJsonString("persons",DataUtil.getPersons());</p><p>  } else if (actionString.equals("strings")) {

   jsonString = JsonTools.createJsonString("strings",DataUtil.getStrings());</p><p>  } else if (actionString.equals("maps")) {

   jsonString = JsonTools.createJsonString("maps",DataUtil.getMaps());

  }

  out.write(jsonString);</p><p> }</p><p> /**
  * Initialization of the servlet. <br>
  *
  * @throws ServletException
  *             if an error occurs
  */
 public void init() throws ServletException {
  // Put your code here
 }</p><p>}
</p>

 通過網址訪問可得到的JSON數據：

二、客戶端解析json數據

這裏暫時只貼出重要的解析部分，

package com.zml.util;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import com.zml.pojo.Person;

/**
 * 解析數據：將json字符串解析還原成原來的數據類型
 *
 * @author 鄭明亮
 * @date 2016-2-3 上午12:11:57
 * @version 1.0
 */
public class JsonTools {

    public static Person getPerson(String key, String jsonString) {
        Person person = new Person();
        // 將json字符串轉換成json對象
        try {
            JSONObject jsonObject = new JSONObject(jsonString);
            // 將json對象根據key(person)，拿到對應的value(Person對象)值
            JSONObject jsonObject2 = jsonObject.getJSONObject(key);
            // 將拿到的對象set到一個person對象中
            person.setName(jsonObject2.getString("name"));
            person.setSex(jsonObject2.getString("sex"));
            person.setQQ(jsonObject2.getString("QQ"));
            person.setContact(jsonObject2.getString("contact"));
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return person;

    }

    public static List<Person> getPersons(String key, String jsonString) {
        List<Person> list = new ArrayList<Person>();
        JSONObject jsonObject;
        try {
            jsonObject = new JSONObject(jsonString);
            JSONArray Persons = jsonObject.getJSONArray(key);
            for (int i = 0; i < Persons.length(); i++) {
                Person person = new Person();
                JSONObject jsonObject2 = Persons.getJSONObject(i);
                person.setName(jsonObject2.getString("name"));
                person.setSex(jsonObject2.getString("sex"));
                person.setQQ(jsonObject2.getString("QQ"));
                person.setContact(jsonObject2.getString("contact"));

                list.add(person);
            }
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return list;
    }

    public static List<String> getStrings(String key, String jsonString) {
        List<String> list = new ArrayList<String>();

        try {
            JSONObject jsonObject = new JSONObject(jsonString);
            JSONArray StringArray = jsonObject.getJSONArray(key);
            for (int i = 0; i < StringArray.length(); i++) {
                String str = StringArray.getString(i);
                list.add(str);

            }

        } catch (Exception e) {
            // TODO: handle exception
        }

        return list;

    }

    public static List<Map<String, Object>> getMaps(String key,
            String jsonString) {
        List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();

        try {
            JSONObject jsonObject = new JSONObject(jsonString);
            JSONArray mapsArray = jsonObject.getJSONArray(key);
            for (int i = 0; i < mapsArray.length(); i++) {
                JSONObject jsonObject2 = mapsArray.getJSONObject(i);
                Map<String, Object> map = new HashMap<String, Object>();
                // 查看Map中的鍵值對的key值
                Iterator<String> iterator = jsonObject2.keys();

                while (iterator.hasNext()) {
                    String json_key = iterator.next();
                    Object json_value = jsonObject2.get(json_key);
                    if(json_value==null){
                        //當鍵值對中的value爲空值時，將value置爲空字符串；
                        json_value="";
                    }
                    map.put(json_key, json_value);
                }
                list.add(map);
            }
        } catch (Exception e) {
            // TODO: handle exception
        }
        return list;
    }

}

需要注意的是上述，客戶端和服務器端雖然都用到了JSONObject類，但是引用的不是一個jar包中的內容哦；客戶端的是引用的 org.json.JSONObject;而服務器端引用的是net.sf.json.JSONObject;