java利用反射将pojo转为json对象

最近做以太坊钱包项目需要与前台进行json交互，写一个工具类，经普通javaBean转为json对象

package util;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.List;

import org.web3j.protocol.core.methods.response.Transaction;

import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;

public class JSONUtil {
    
    /**
     * 获取Transaction相应的JSON对象
     * @param trans
     * @return
     */
    public static JSONObject getTransJSON(Transaction trans) {
        JSONObject data = getJSON(Transaction.class, trans);
        return data;
    }
    
    /**
     * 获取交易信息列表
     * @param transList
     * @return
     */
    public static JSONArray getTransListJSON(List<Transaction> transList) {
        JSONArray data = new JSONArray();
        for(Transaction trans : transList) {
            JSONObject transJson = getTransJSON(trans);
            data.add(transJson);
        }
        return data;
    }
    
    /**
     * 获取json对象
     * @param cls
     * @param obj
     * @return
     */
    public static JSONObject getJSON(Class<?> cls, Object obj) {
        JSONObject json = new JSONObject();
        Field[] fieldArray = cls.getDeclaredFields();
        for(Field field : fieldArray) {
            String fieldName = field.getName();
            String methodName = "get" + fieldName.substring(0, 1).toUpperCase() + fieldName.substring(1);
            try {
                Method method = cls.getMethod(methodName);
                Object fieldObject = method.invoke(obj, new Object[0]); 
                String fieldValue = null; 
                if(fieldObject != null) {
                    fieldValue = fieldObject.toString();
                } 
                json.put(fieldName, fieldValue);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return json;
    }
    
}