Java单个对象和List对象转换成Json，Json转List

淩亂°似流年 2022-05-05 09:34 2983阅读 0赞

**目录**

（一）使用单个对象转换JSON对象

（二）多个对象存到List，再转换成JSON

（三）json的list对象转List对象

--------------------

# （一）使用单个对象转换JSON对象 #

import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    
    import org.apache.commons.lang.StringUtils;
    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    import org.junit.Test;
    
    import com.css.eshop.exception.DataAccessException;
    import com.css.eshop.model.VoucherInfo;
    import com.css.eshop.util.HttpClientUtil;
    import com.css.eshop.util.LoadStaticReferenceTables;
    
    import net.sf.json.JSONArray;
    import net.sf.json.JSONObject;
    
    public class TestPut {
    	protected Log logger = LogFactory.getLog(this.getClass().getName());
    	
    	@Test
    	public void getOneJson(){//测试转换成Json,单个对象
    		VoucherInfo vo1=new VoucherInfo();
    		vo1.setVoucherValue(2131);vo1.setVoucherCode("小可爱的");
    		JSONObject updateJsonObj = JSONObject.fromObject(vo1);//转换成json格式
    		logger.info("---转换成json格式:---"+updateJsonObj.toString());//提取access_token节点数据
    	}
    }

输出转换后日志：

![70][]

17-10-2018 17:35 INFO  TestPut:35 - ---转换成json格式:---\{"labourCost":0,"refMetalPrice":0,"voucherCoNumber":"","voucherCode":"小可爱的","voucherType":"","voucherValue":2131,"weight":0,"weightUnit":""\}

# （二）多个对象存到List，再转换成JSON #

@Test
    	public void getArrayList(){//测试转换成Json，List转换成JSONList
    		List<VoucherInfo> vouchersList=new ArrayList<VoucherInfo>();
    		VoucherInfo vo1=new VoucherInfo();
    		VoucherInfo vo2=new VoucherInfo();
    		vo1.setVoucherValue(2131);vo1.setVoucherCode("小可爱的");
    		vo2.setVoucherValue(100);vo2.setVoucherCode("小可爱的222");
    		vouchersList.add(vo1);vouchersList.add(vo2);
    		JSONArray jsonArray = JSONArray.fromObject(vouchersList);
    		logger.info("--获取到转换为json格式的内容:"+jsonArray.toString());//提取access_token节点数据
    		
    	}

输出日志：

![70 1][]

17-10-2018 17:36 INFO  TestPut:47 - --获取到转换为json格式的内容:\[\{"labourCost":0,"refMetalPrice":0,"voucherCoNumber":"","voucherCode":"小可爱的","voucherType":"","voucherValue":2131,"weight":0,"weightUnit":""\},\{"labourCost":0,"refMetalPrice":0,"voucherCoNumber":"","voucherCode":"小可爱的222","voucherType":"","voucherValue":100,"weight":0,"weightUnit":""\}\]

# （三）json的list对象转List对象 #

先转jsonArray，再转object提取数据

@Test
    	public void test1210() {
    		List<VoucherInfo> vouchers=new ArrayList<VoucherInfo>();
    		VoucherInfo voucherInfo1=new VoucherInfo();VoucherInfo voucherInfo2=new VoucherInfo();
    		voucherInfo1.setVoucherCode("coupncdeC0000003");voucherInfo1.setVoucherType("DISC_VOUCHER");
    		voucherInfo1.setVoucherCoNumber(null);voucherInfo1.setLabourCost(0.0);voucherInfo1.setWeight(0.0);
    		voucherInfo1.setVoucherValue(1000.0);voucherInfo1.setRefMetalPrice(0.0);
    		
    		voucherInfo2.setVoucherCode("coupncdeC0000001");voucherInfo2.setVoucherType("DISC_VOUCHER");
    		voucherInfo2.setVoucherCoNumber(null);voucherInfo2.setLabourCost(0.0);voucherInfo2.setWeight(0.0);
    		voucherInfo2.setVoucherValue(1000.0);voucherInfo2.setRefMetalPrice(0.0);
    		vouchers.add(voucherInfo1);vouchers.add(voucherInfo2);
    		double ecoupon_amt=0;
    		if(null != vouchers  && vouchers.size()>0){
    			JSONArray vouchersListJsonArray = JSONArray.fromObject(vouchers);
    			String vouchersListJson=vouchersListJsonArray.toString();
    			
    			System.out.println(vouchersListJson);
    			if(null != vouchersListJson){
    				JSONArray jsonArray1 = JSONArray.fromObject(vouchersListJson);
    				//循环获取json数组中的 json 对象，然后转换为 object
    		        for (int j = 0; j < jsonArray1.size(); j++) {  
    		            JSONObject jsonObject2 = jsonArray1.getJSONObject(j);  
    		            VoucherInfo cust = (VoucherInfo) JSONObject.toBean(jsonObject2, VoucherInfo.class);  
    		            ecoupon_amt=ecoupon_amt+cust.getVoucherValue();
    		        }  
    			}
    		}
    		System.out.println(ecoupon_amt);
    	}

[70]: /images/20220505/6154cee652f4419ca9bd1295d9dae792.png
[70 1]: /images/20220505/854066577f00418696c629cc2ef12cf5.png