Java JSON解析的两种常用方式

Java常用的解析JSON的方式有两种，一种是JSON-lib，一种是org.json。

JSON-lib:

依赖包:

     commons-beanutils.jar

     commons-collections.jar

     commons-lang.jar

     commons-logging.jar

     ezmorph.jar

     json-lib.jar

基本方法介绍:

     List、数组转换为json     

JSONArray.fromObject(list) or JSONArray.fromObject(arr)

     Map、bean转换为json    

JSONObject.fromObject(map) or JSONObject.fromObject(beanname)

     普通字符串转换为json         

JSONObject.fromObject("{'name':'zs'}") or JSONArray.fromObject("['zs','ls','ww']")

示例:

package net.hkh.json;import java.util.HashMap;import java.util.ArrayList;import java.util.List;import java.util.Map;import net.sf.json.JSONArray;import net.sf.json.JSONObject;/* * JSONTest类 */public class JSONTest{     /* * 解析JSON数据      */     public static void parseJSON(String jsonString){          JSONObject jb=JSONObject.fromObject(jsonString);          JSONObject ja=jb.getJSONArray("employee");          List<Employee>empList=new ArrayList<Employee>();          for(int i=0;i<ja.size();i++){               Employee emp=new Employee();               emp.setName(ja.getJSONObject(i).getString("name"));               emp.setSex(ja.getJSONObject(i).getString("sex"));               emp.setAge(ja.getJSONObject(i).getInt("age"));               empList.add(emp);          }          System.out.println("\n将JSON数据转换为Employee对象:");          for(int i=0;i<empList.size();i++){               Employee emp=empList.get(i);               System.out.println("name:"+emp.getName()+"sex:"+emp.getSex()+"age:"+emp.getAge());          }     }     /*      * 构造JSON数据      */     public static String buildJSON(){          JSONObject jo=new JSONObject();          Map<String,String>map1=new HashMap<String,String>();          map1.put("name","zs");          map1.put("sex","female");          map1.put("age","23");          Map<String,String>map2=new HashMap<String,String>();          map2.put("name","ls");          map2.put("sex","male");          map2.put("age","24");          List<Map<String,String>>list=new ArrayList<Map<String,String>>();          list.add(map1);          list.add(map2);          Employee emp=new Employee();          emp.setName("ww");          emp.setSex("male");          emp.setAge(25);          JSONArray ja1=JSONArray.fromObject(map1);          JSONArray ja2=JSONArray.fromObject(list);          JSONArray ja3=JSONArray.fromObject(employee);          System.out.println("JSONArray对象数据格式:");          System.out.println(ja1.toString());          System.out.println(ja2.toString());          System.out.println(ja3.toString());          jo.put("map",ja1);          jo.put("employee",ja2);          System.out.println("\n最终构造的JSON数据格式:");          System.out.println(jo.toString());          return jo.toString();     }          /*      * main方法      */     public static void main(String[]args){          parseJSON(buildJSON());     }}/* * Employee类 */class Employee {       private String name ;       private String sex ;       private int age ;       public Employee() {      }       public Employee(String name, String sex, int age) {             this.name = name;             this.sex = sex;             this.age = age;      }       public String getName() {             return name ;      }       public void setName(String name) {             this.name = name;      }       public String getSex() {             return sex ;      }       public void setSex(String sex) {             this.sex = sex;      }       public int getAge() {             return age ;      }       public void setAge(int age) {             this.age = age;      }       public String toString() {             return name + "," + sex + "," + age;      }}

========================================================================

org.json

依赖包:

     json.org.jar

基本方法介绍:

     org.json不能直接与bean进行转换，需要通过map进行中转

     1.将bean转换为Map:

public static Map toMap(Object bean) {Map rslt = new HashMap();Method[] methods = bean.getClass().getDeclaredMethods();for (Method method : methods) {try {if (method.getName().startsWith("get")) {String field = method.getName();field = field.substring(field.indexOf("get") + 3);field = field.toLowerCase().charAt(0) + field.substring(1);Object value = method.invoke(bean, (Object[]) null);rslt.put(field, null == value ? "" : value.toString());}} catch (Exception e) {e.printStackTrace();}}return rslt;}

2.将json转换为Map

public static Map toMap(String jsonString) throws JSONException {JSONObject obj = new JSONObject(jsonString);Map rslt = new HashMap();Iterator iter = obj.keys();String key = null;String value = null;while (iter.hasNext()) {key = (String) iter.next();value = obj.getString(key);rslt.put(key, value);}return rslt;}

 3.将Map转换为JavaBean

public static Object toJavaBean(Object bean, Map data) {Method[] methods = bean.getClass().getDeclaredMethods();for (Method method : methods) {try {if (method.getName().startsWith("set")) {String field = method.getName();field = field.substring(field.indexOf("set") + 3);field = field.toLowerCase().charAt(0) + field.substring(1);method.invoke(bean, new Object[] { data.get(field) });}} catch (Exception e) {e.printStackTrace();}}return bean;}

4.将JSON转换为JavaBean

public static Object toJavaBean(Object bean, String jsonString)throws JSONException {return toJavaBean(bean, toMap(jsonString));}

==========================================

json-lib与org.json比较:

     1.org.json比json-lib要轻量得多，前者没有依赖其他任何jar包，而后者要依赖ezmorph和commons的lang、loggin、beanutils、collections等组件

     2.json-lib在构造bean和解析bean时比org.json要方便得多，json-lib可与JavaBean直接互转，而org.json不能与JavaBean进行直接转换需要通过Map进行中转，即先将JavaBean转换为Map，然后再将Map转换为JavaBean