jsonutil.java

因为许多人出去吃饭都一个人付帐

package cn.com.sdcncsi.lunch.utils;

import java.lang.reflect.Array;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;

import org.codehaus.jettison.json.JSONArray;
import org.codehaus.jettison.json.JSONException;
import org.codehaus.jettison.json.JSONObject;
import org.codehaus.jettison.json.JSONString;

/**
* JSON工具类，反射的方式转换整个对象
* @author 
*
*/
public class JSONUtil{

	   private static JSONUtil instance = null;
	    
	   public JSONUtil(){}
	   
	   /**
	    * 代理类时做的检查.返回应该检查的对象.
	    * @param bean
	    * @return
	    */
	    protected Object proxyCheck(Object bean){
	        return bean;
	    }

	    static public String toJSONString(Object obj) throws JSONException{
	        return toJSONString(obj, false);
	    }
	    
	    static public String toJSONString(Object obj, boolean useClassConvert) throws JSONException{
	        if(instance == null)
	            instance = new JSONUtil();
	        return instance.getJSONObject(obj, useClassConvert).toString();
	    }

	    private String getJSONArray(Object arrayObj, boolean useClassConvert) throws JSONException{
	        
	        if(arrayObj == null)
	            return "null";
	        
	        arrayObj = proxyCheck(arrayObj);
	        
	        JSONArray jSONArray = new JSONArray();
	        if(arrayObj instanceof Collection){
	            Iterator iterator = ((Collection)arrayObj).iterator();
	            while(iterator.hasNext()){
	                Object rowObj = iterator.next();
	                if(rowObj == null)
	                    jSONArray.put(new JSONStringObject(null));
	                else if(rowObj.getClass().isArray() || rowObj instanceof Collection)
	                    jSONArray.put(getJSONArray(rowObj, useClassConvert));
	                else
	                    jSONArray.put(getJSONObject(rowObj, useClassConvert));
	            }
	        }
	        if(arrayObj.getClass().isArray()){
	            int arrayLength = Array.getLength(arrayObj);
	            for(int i = 0; i < arrayLength; i ++){
	                Object rowObj = Array.get(arrayObj, i);
	                if(rowObj == null)
	                    jSONArray.put(new JSONStringObject(null));
	                else if(rowObj.getClass().isArray() || rowObj instanceof Collection)
	                    jSONArray.put(getJSONArray(rowObj, useClassConvert));
	                else
	                    jSONArray.put(getJSONObject(rowObj, useClassConvert));
	            }
	        }
	        return jSONArray.toString();
	    }

	    JSONStringObject getJSONObject(Object value, boolean useClassConvert) throws JSONException{

	        //处理原始类型
	        if (value == null) {
	            return new JSONStringObject("null");
	        }
	        value = proxyCheck(value);
	        if (value instanceof JSONString) {
	            Object o;
	            try {
	                o = ((JSONString)value).toJSONString();
	            } catch (Exception e) {
	                throw new JSONException(e);
	            }
	            throw new JSONException("Bad value from toJSONString: " + o);
	        }
	        if (value instanceof Number){
	            return new JSONStringObject(JSONObject.numberToString((Number) value));
	        }
	        if (value instanceof Boolean || value instanceof JSONObject ||
	                value instanceof JSONArray) {
	            return new JSONStringObject(value.toString());
	        }
	        if (value instanceof String)
	            return new JSONStringObject(JSONObject.quote(value.toString()));
	        if (value instanceof Map) {
	            
	            JSONObject jSONObject = new JSONObject();

	            Iterator iterator = ((Map)value).keySet().iterator();
	            while(iterator.hasNext()){
	                String key = iterator.next().toString();
	                Object valueObj = ((Map)value).get(key);
	                jSONObject.put(key, getJSONObject(valueObj, useClassConvert));
	            }
	            return new JSONStringObject(jSONObject.toString());
	        }

	        //class
	        if(value instanceof Class)
	            return new JSONStringObject(JSONObject.quote(((Class)value).getSimpleName()));
	        
	        //数组
	        if (value instanceof Collection || value.getClass().isArray()) {
	            return new JSONStringObject(getJSONArray(proxyCheck(value), useClassConvert));
	        }

	        return reflectObject(value, useClassConvert);
	    }//value.equals(null)

	    private JSONStringObject reflectObject(Object bean, boolean useClassConvert) {
	        JSONObject jSONObject = new JSONObject();

	        Class klass = bean.getClass();
	        Method[] methods = klass.getMethods();
	        for (int i = 0; i < methods.length; i += 1) {
	            try {
	                Method method = methods[i];
	                String name = method.getName();
	                String key = "";
	                if (name.startsWith("get")) {
	                    key = name.substring(3);
	                } else if (name.startsWith("is")) {
	                    key = name.substring(2);
	                }
	                if (key.length() > 0 &&
	                        Character.isUpperCase(key.charAt(0)) &&
	                        method.getParameterTypes().length == 0) {
	                    if (key.length() == 1) {
	                        key = key.toLowerCase();
	                    } else if (!Character.isUpperCase(key.charAt(1))) {
	                        key = key.substring(0, 1).toLowerCase() +
	                            key.substring(1);
	                    }
	                    Object elementObj = method.invoke(bean, null);
	                    if(!useClassConvert && elementObj instanceof Class)
	                        continue;

	                    jSONObject.put(key, getJSONObject(elementObj, useClassConvert));
	                }
	            } catch (Exception e) {
	                 /* forget about it */
	            }
	        }
	        return new JSONStringObject(jSONObject.toString());
	    }
	}