Java：Json与其他Java对象集合的转换

一、引入的jar包

　　json-lib-2.4-jdk15.jar

　　

二、Json字符串转换为其他对象

　　1、对象==》json字符串　　2、list和Map集合==》json字符串　　3、Map集合==》json字符串【具体代码如下】

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.TreeMap;

import com.coscon.ferightEntrust.vo.CdViewVo;

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

public class TestCd {
    public static void main(String[] args) {
        collectToStr();
    }
    
    private static void collectToStr(){
       
        CdViewVo cvv=new CdViewVo();
        cvv.setCntrNum("CBHU898637"); cvv.setSealNum("CBHU898637");
        cvv.setCntrType("20Gp"); cvv.setObTrafficTerm("jkd");
        cvv.setIbTrafficTerm("P-预付"); cvv.setPackDesc("12");
        cvv.setGrossWt("100"); cvv.setVol("54.23");
        
        CdViewVo cvv2=new CdViewVo();
        cvv2.setCntrNum("CBHU893437"); cvv2.setSealNum("CBHU893437");
        cvv2.setCntrType("40Gp"); cvv2.setObTrafficTerm("bhc");
        cvv2.setIbTrafficTerm("P-预付"); cvv2.setPackDesc("21");
        cvv2.setGrossWt("10"); cvv2.setVol("84.23");
        //Java对象
        JSONObject cvvo=JSONObject.fromObject(cvv);
        String cvvs=cvvo.toString();
        System.out.println("CdViewVo的json字符串："+cvvs);
        //map集合
        Map<String, String> tm=new TreeMap<String, String>();
        tm.put("a", "ddd");   tm.put("b", "ccc");
        tm.put("c", "bbb");   tm.put("d", "aaa");
        JSONArray array=JSONArray.fromObject(tm);
        String tmstr=array.toString();
        System.out.println("Map集合对应的json字符串："+tmstr);
        
        //list集合
        List<CdViewVo> list=new ArrayList<CdViewVo>();
        list.add(cvv);
        list.add(cvv2);
        JSONArray listArr=JSONArray.fromObject(list);
        String listStr=listArr.toString();
        System.out.println("listStr集合对应的json字符串："+listStr);
    }
}

运行结果如下：

CdViewVo的json字符串：{"cntrNum":"CBHU898637","cntrType":"20Gp","grossWt":"100","ibTrafficTerm":"P-预付","obTrafficTerm":"jkd","packDesc":"12","packNum":"","sealNum":"CBHU898637","vol":"54.23"}
Map集合对应的json字符串：[{"a":"ddd","b":"ccc","c":"bbb","d":"aaa"}]
listStr集合对应的json字符串：[{"cntrNum":"CBHU898637","cntrType":"20Gp","grossWt":"100","ibTrafficTerm":"P-预付","obTrafficTerm":"jkd","packDesc":"12","packNum":"","sealNum":"CBHU898637","vol":"54.23"},
{"cntrNum":"CBHU893437","cntrType":"40Gp","grossWt":"10","ibTrafficTerm":"P-预付","obTrafficTerm":"bhc","packDesc":"21","packNum":"","sealNum":"CBHU893437","vol":"84.23"}]

三、Java对象转换为Json字符串

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

public class TestCd {
    public static void main(String[] args) {
        jsonStrToJava();
    }
    private static void jsonStrToJava(){
        String jsonStr="{"cntrNum":"CBHU898637","cntrType":"20Gp","grossWt":"100"," +
                                ""ibTrafficTerm":"P-预付","obTrafficTerm":"jkd","packDesc":"12"," +
                                ""packNum":"","sealNum":"CBHU898637","vol":"54.23"}";
        JSONObject java=JSONObject.fromObject(jsonStr);
        CdViewVo cvv=(CdViewVo) JSONObject.toBean(java,CdViewVo.class);
        System.out.println("cntrNum:  "+cvv.getCntrNum());
    }
}

运行结果：

cntrNum:  CBHU898637

四、集合转换为Json字符串

　　

String str = "{"lendperson":"李四","lendcompany":"有限公司","checkperson":"李四",
  "lenddate":"2010-07-19T00:00:00","lendcounts":4,"
  passports":[{"passportid":"d","name":"李豫川","passporttype":"K"},
  {"passportid":"K9051","name":"李平","passporttype":"K"},
  {"passportid":"K90517","name":"袁寒梅","passporttype":"K"},
  {"passportid":"K905199","name":"贺明","passporttype":"K"}]}";


  JSONObject jsonobject = JSONObject.fromObject(str);
  PassportLendsEntity passportlends = null;
  try {
   //获取一个json数组
   JSONArray array = jsonobject.getJSONArray("passports");
   //将json数组 转换成 List<PassPortForLendsEntity>泛型
   List<PassPortForLendsEntity> list = new ArrayList<PassPortForLendsEntity>();
   for (int i = 0; i < array.size(); i++) {   
            JSONObject object = (JSONObject)array.get(i);  
            PassPortForLendsEntity passport = (PassPortForLendsEntity)JSONObject.toBean(object,
              PassPortForLendsEntity.class);  //转换成Java对象
            if(passport != null){
             list.add(passport);
            }  
     }