Java操作json的通用类.

package com.baiyyy.polabs.util.json;         
        
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import net.sf.json.JsonConfig;
import net.sf.json.util.CycleDetectionStrategy;
        
/**      
 * 处理json的工具类，负责json数据转换成java对象和java对象转换成json      
 *       
 * @author yongtree      
 * @date 2008-11-22 上午10:47:13      
 * @version 1.0      
 */        
public class JsonUtil {         
        
    /**      
     * 从一个JSON 对象字符格式中得到一个java对象      
     *       
     * @param jsonString      
     * @param pojoCalss      
     * @return      
     */        
    public static Object  getObject4JsonString(String jsonString, Class pojoCalss) {         
        Object pojo;         
        JSONObject jsonObject = JSONObject.fromObject(jsonString);         
        pojo = JSONObject.toBean(jsonObject, pojoCalss);         
        return pojo;         
    }         
        
        
    /**      
     * 从json HASH表达式中获取一个map，改map支持嵌套功能      
     *       
     * @param jsonString      
     * @return      
     */        
    public static Map getMap4Json(String jsonString) {         
        JSONObject jsonObject = JSONObject.fromObject(jsonString);         
        Iterator keyIter = jsonObject.keys();         
        String key;         
        Object value;         
        Map valueMap = new HashMap();         
        
        while (keyIter.hasNext()) {         
            key = (String) keyIter.next();         
            value = jsonObject.get(key);         
            valueMap.put(key, value);         
        }         
        
        return valueMap;         
    }         
        
        
    /**      
     * 从json数组中得到相应java数组      
     *       
     * @param jsonString      
     * @return      
     */        
    public static Object[] getObjectArray4Json(String jsonString) {         
        JSONArray jsonArray = JSONArray.fromObject(jsonString);         
        return jsonArray.toArray();         
        
    }         
        
        
    /**      
     * 从json对象集合表达式中得到一个java对象列表      
     *       
     * @param jsonString      
     * @param pojoClass      
     * @return      
     */        
    public static List getList4Json(String jsonString, Class pojoClass) {         
        
        JSONArray jsonArray = JSONArray.fromObject(jsonString);         
        JSONObject jsonObject;         
        Object pojoValue;         
        
        List list = new ArrayList();         
        for (int i = 0; i < jsonArray.size(); i++) {         
        
            jsonObject = jsonArray.getJSONObject(i);         
            pojoValue = JSONObject.toBean(jsonObject, pojoClass);         
            list.add(pojoValue);         
        
        }         
        return list;         
        
    }         
        
        
    /**      
     * 从json数组中解析出java字符串数组      
     *       
     * @param jsonString      
     * @return      
     */        
    public static String[] getStringArray4Json(String jsonString) {         
        
        JSONArray jsonArray = JSONArray.fromObject(jsonString);         
        String[] stringArray = new String[jsonArray.size()];         
        for (int i = 0; i < jsonArray.size(); i++) {         
            stringArray[i] = jsonArray.getString(i);         
        
        }         
        
        return stringArray;         
    }         
        
        
    /**      
     * 从json数组中解析出javaLong型对象数组      
     *       
     * @param jsonString      
     * @return      
     */        
    public static Long[] getLongArray4Json(String jsonString) {         
        
        JSONArray jsonArray = JSONArray.fromObject(jsonString);         
        Long[] longArray = new Long[jsonArray.size()];         
        for (int i = 0; i < jsonArray.size(); i++) {         
            longArray[i] = jsonArray.getLong(i);         
        
        }         
        return longArray;         
    }         
        
        
    /**      
     * 从json数组中解析出java Integer型对象数组      
     *       
     * @param jsonString      
     * @return      
     */        
    public static Integer[] getIntegerArray4Json(String jsonString) {         
        
        JSONArray jsonArray = JSONArray.fromObject(jsonString);         
        Integer[] integerArray = new Integer[jsonArray.size()];         
        for (int i = 0; i < jsonArray.size(); i++) {         
            integerArray[i] = jsonArray.getInt(i);         
        
        }         
        return integerArray;         
    }         
        
    /**      
     * 从json数组中解析出java Date 型对象数组，使用本方法必须保证      
     *       
     * @param jsonString      
     * @return      
     * @throws ParseException      
     */        
    public static Date[] getDateArray4Json(String jsonString, String DataFormat)         
            throws ParseException {         
        
        JSONArray jsonArray = JSONArray.fromObject(jsonString);         
        Date[] dateArray = new Date[jsonArray.size()];         
        String dateString;         
        Date date;         
        
        for (int i = 0; i < jsonArray.size(); i++) {         
            dateString = jsonArray.getString(i);         
            date = DateUtil.parseDate(dateString, DataFormat);         
            dateArray[i] = date;         
        
        }         
        return dateArray;         
    }         
        
        
    /**      
     * 从json数组中解析出java Integer型对象数组      
     *       
     * @param jsonString      
     * @return      
     */        
    public static Double[] getDoubleArray4Json(String jsonString) {         
        
        JSONArray jsonArray = JSONArray.fromObject(jsonString);         
        Double[] doubleArray = new Double[jsonArray.size()];         
        for (int i = 0; i < jsonArray.size(); i++) {         
            doubleArray[i] = jsonArray.getDouble(i);         
        
        }         
        return doubleArray;         
    }         
        
        
    /**      
     * 将java对象转换成json字符串      
     *       
     * @param javaObj      
     * @return      
     */        
    public static String getJsonString4JavaPOJO(Object javaObj) {         
        
        JSONObject json;         
        json = JSONObject.fromObject(javaObj);         
        return json.toString();         
        
    }         
        
    /**      
     * 将java对象转换成json字符串,并设定日期格式      
     *       
     * @param javaObj      
     * @param dataFormat      
     * @return      
     */        
    public static String getJsonString4JavaPOJO(Object javaObj,         
            String dataFormat) {         
        
        JSONObject json;         
        JsonConfig jsonConfig = configJson(dataFormat);         
        json = JSONObject.fromObject(javaObj, jsonConfig);         
        return json.toString();         
        
    }         
        
    /**      
     * JSON 时间解析器具      
     *       
     * @param datePattern      
     * @return      
     */        
    public static JsonConfig configJson(String datePattern) {         
        JsonConfig jsonConfig = new JsonConfig();         
        jsonConfig.setExcludes(new String[] { "" });         
        jsonConfig.setIgnoreDefaultExcludes(false);         
        jsonConfig.setCycleDetectionStrategy(CycleDetectionStrategy.LENIENT);         
        jsonConfig.registerJsonValueProcessor(Date.class,         
                new JsonDateValueProcessor(datePattern));         
        
        return jsonConfig;         
    }         
        
        
    /**      
     * 除去不想生成的字段（特别适合去掉级联的对象）+时间转换      
     * @param excludes 除去不想生成的字段      
     * @param datePattern      
     * @return      
     */        
    public static JsonConfig configJson(String[] excludes, String datePattern) {         
        JsonConfig jsonConfig = new JsonConfig();         
        jsonConfig.setExcludes(excludes);         
        jsonConfig.setIgnoreDefaultExcludes(true);         
        jsonConfig.setCycleDetectionStrategy(CycleDetectionStrategy.LENIENT);         
        jsonConfig.registerJsonValueProcessor(Date.class,         
                new JsonDateValueProcessor(datePattern));         
        
        return jsonConfig;         
    }         
        
}    

*******************************************************************************************
日期转换
*******************************************************************************************

package com.baiyyy.polabs.util.json;         
        
import java.text.SimpleDateFormat;         
import java.util.Date;         
        
import net.sf.json.JsonConfig;         
import net.sf.json.processors.JsonValueProcessor;         
        
/**      
 *       
 * @author yongtree      
 * @date 2008-11-22 上午10:54:19      
 * @version 1.0      
 */        
public class JsonDateValueProcessor implements JsonValueProcessor {            
               
    private String format = "yyyy-MM-dd HH:mm:ss";            
           
    public JsonDateValueProcessor() {            
           
    }            
           
    public JsonDateValueProcessor(String format) {            
        this.format = format;            
    }            
           
    public Object processArrayValue(Object value, JsonConfig jsonConfig) {            
        String[] obj = {};            
        if (value instanceof Date[]) {            
            SimpleDateFormat sf = new SimpleDateFormat(format);            
            Date[] dates = (Date[]) value;            
            obj = new String[dates.length];            
            for (int i = 0; i < dates.length; i++) {            
                obj[i] = sf.format(dates[i]);            
            }            
        }            
        return obj;            
    }            
           
    public Object processObjectValue(String key, Object value, JsonConfig jsonConfig) {            
        if (value instanceof Date) {            
            String str = new SimpleDateFormat(format).format((Date) value);            
            return str;            
        }            
        return value == null ? null : value.toString();            
    }            
           
    public String getFormat() {            
        return format;            
    }            
           
    public void setFormat(String format) {            
        this.format = format;            
    }            
           
}