fastjson json数组字符串形式转为对象列表

package com.ming.ams;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.alibaba.fastjson.TypeReference;
    
    
public class TestFastJson {      
    public static void main(String[] args) {      
        //  转换成对象      
        String jsonstring = "{\"a\":51,\"b\":0}";      
        Usa u1 = JSON.parseObject(jsonstring, new TypeReference<Usa>(){});    
        Usa u2 = JSON.parseObject(jsonstring,Usa.class);    
        // 转换成对象数组       
        String jsonstring2 = "[{\"a\":51,\"b\":0}]";      
        Usa[] usa2 = JSON.parseObject(jsonstring2, new TypeReference<Usa[]>(){});      
        List list = Arrays.asList(usa2);   
        // 转换成ArrayList  
        ArrayList<Usa> list2 = JSON.parseObject(jsonstring2, new TypeReference<ArrayList<Usa>>(){});   
          
        // 转换成ArrayList(默认)    list3  与 list4  效果相同  
        ArrayList<JSONObject> list3 = JSON.parseObject(jsonstring2, new ArrayList<Usa>().getClass());   
        ArrayList<JSONObject> list4 = JSON.parseObject(jsonstring2, ArrayList.class);   
        for (int i = 0; i < list4.size(); i++) { //  推荐用这个  
            JSONObject io = list4.get(i);  
            System.out.println(io.get("a") + "======adn====="+io.get("b"));  
        }  
    }      
}      
class Usa {  
    private int count = 1888;  
    private String base = "project";  
    private Long a;      
    public Long getA() {      
        return a;      
    }      
    public void setA(Long a) {      
        this.a = a;      
    }      
    private String b;      
    public String getB() {      
        return b;      
    }      
    public void setB(String b) {      
        this.b = b;      
    }      
}