JAVA对象转换成JSON字符串

package com.jetsum.util; 
 
import java.io.StringReader; 
import java.lang.reflect.Field; 
import java.util.ArrayList; 
import java.util.List; 
import java.util.Map; 
import java.util.Set; 
 
import antlr.RecognitionException; 
import antlr.TokenStreamException; 
 
import com.sdicons.json.mapper.JSONMapper; 
import com.sdicons.json.mapper.MapperException; 
import com.sdicons.json.model.JSONArray; 
import com.sdicons.json.model.JSONValue; 
import com.sdicons.json.parser.JSONParser; 
 
public class JsonUtil { 
 
    /**
     * JAVA对象转换成JSON字符串
     * @param obj
     * @return
     * @throws MapperException
     */  
    public static String objectToJsonStr(Object obj) throws MapperException{ 
        JSONValue jsonValue = JSONMapper.toJSON(obj);   
        String jsonStr = jsonValue.render(false); 
        return jsonStr; 
    } 
     
    /**
     * 重载objectToJsonStr方法
     * @param obj 需要转换的JAVA对象
     * @param format 是否格式化
     * @return
     * @throws MapperException
     */ 
    public static String objectToJsonStr(Object obj,boolean format) throws MapperException{ 
        JSONValue jsonValue = JSONMapper.toJSON(obj);   
        String jsonStr = jsonValue.render(format); 
        return jsonStr; 
    }    
     
    /**
     * JSON字符串转换成JAVA对象
     * @param jsonStr
     * @param cla
     * @return
     * @throws MapperException
     * @throws TokenStreamException
     * @throws RecognitionException
     */ 
    @SuppressWarnings({ "rawtypes", "unchecked" }) 
    public static Object jsonStrToObject(String jsonStr,Class<?> cla) throws MapperException, TokenStreamException, RecognitionException{ 
        Object obj = null; 
        try{ 
            JSONParser parser = new JSONParser(new StringReader(jsonStr));     
            JSONValue jsonValue = parser.nextValue();            
            if(jsonValue instanceof com.sdicons.json.model.JSONArray){ 
                List list = new ArrayList(); 
                JSONArray jsonArray = (JSONArray) jsonValue; 
                for(int i=0;i<jsonArray.size();i++){ 
                    JSONValue jsonObj = jsonArray.get(i); 
                    Object javaObj = JSONMapper.toJava(jsonObj,cla);  
                    list.add(javaObj); 
                } 
                obj = list; 
            }else if(jsonValue instanceof com.sdicons.json.model.JSONObject){ 
                obj = JSONMapper.toJava(jsonValue,cla);  
            }else{ 
                obj = jsonValue; 
            } 
        }catch(Exception e){ 
            e.printStackTrace(); 
        } 
        return obj;  
    } 
     
    /**
     * 将JAVA对象转换成JSON字符串
     * @param obj
     * @return
     * @throws IllegalArgumentException
     * @throws IllegalAccessException
     */ 
    @SuppressWarnings("rawtypes") 
    public static String simpleObjectToJsonStr(Object obj,List<Class> claList) throws IllegalArgumentException, IllegalAccessException{ 
        if(obj==null){ 
            return "null"; 
        } 
        String jsonStr = "{"; 
        Class<?> cla = obj.getClass(); 
        Field fields[] = cla.getDeclaredFields(); 
        for (Field field : fields) { 
            field.setAccessible(true); 
            if(field.getType() == long.class){ 
                jsonStr += "\""+field.getName()+"\":"+field.getLong(obj)+","; 
            }else if(field.getType() == double.class){ 
                jsonStr += "\""+field.getName()+"\":"+field.getDouble(obj)+","; 
            }else if(field.getType() == float.class){ 
                jsonStr += "\""+field.getName()+"\":"+field.getFloat(obj)+","; 
            }else if(field.getType() == int.class){ 
                jsonStr += "\""+field.getName()+"\":"+field.getInt(obj)+","; 
            }else if(field.getType() == boolean.class){ 
                jsonStr += "\""+field.getName()+"\":"+field.getBoolean(obj)+","; 
            }else if(field.getType() == Integer.class||field.getType() == Boolean.class 
                    ||field.getType() == Double.class||field.getType() == Float.class                    
                    ||field.getType() == Long.class){                
                jsonStr += "\""+field.getName()+"\":"+field.get(obj)+","; 
            }else if(field.getType() == String.class){ 
                jsonStr += "\""+field.getName()+"\":\""+field.get(obj)+"\","; 
            }else if(field.getType() == List.class){ 
                String value = simpleListToJsonStr((List<?>)field.get(obj),claList); 
                jsonStr += "\""+field.getName()+"\":"+value+",";                 
            }else{       
                if(claList!=null&&claList.size()!=0&&claList.contains(field.getType())){ 
                    String value = simpleObjectToJsonStr(field.get(obj),claList); 
                    jsonStr += "\""+field.getName()+"\":"+value+",";                     
                }else{ 
                    jsonStr += "\""+field.getName()+"\":null,"; 
                } 
            } 
        } 
        jsonStr = jsonStr.substring(0,jsonStr.length()-1); 
        jsonStr += "}"; 
            return jsonStr;      
    } 
     
    /**
     * 将JAVA的LIST转换成JSON字符串
     * @param list
     * @return
     * @throws IllegalArgumentException
     * @throws IllegalAccessException
     */ 
    @SuppressWarnings("rawtypes") 
    public static String simpleListToJsonStr(List<?> list,List<Class> claList) throws IllegalArgumentException, IllegalAccessException{ 
        if(list==null||list.size()==0){ 
            return "[]"; 
        } 
        String jsonStr = "["; 
        for (Object object : list) { 
            jsonStr += simpleObjectToJsonStr(object,claList)+","; 
        } 
        jsonStr = jsonStr.substring(0,jsonStr.length()-1); 
        jsonStr += "]";      
        return jsonStr; 
    }    
     
    /**
     * 将JAVA的MAP转换成JSON字符串，
     * 只转换第一层数据
     * @param map
     * @return
     */ 
    public static String simpleMapToJsonStr(Map<?,?> map){ 
        if(map==null||map.isEmpty()){ 
            return "null"; 
        } 
        String jsonStr = "{"; 
        Set<?> keySet = map.keySet(); 
        for (Object key : keySet) { 
            jsonStr += "\""+key+"\":\""+map.get(key)+"\",";      
        } 
        jsonStr = jsonStr.substring(0,jsonStr.length()-1); 
        jsonStr += "}"; 
        return jsonStr; 
    } 
}