ps：看这篇博客之前首先要引入工具包json-lib-2.2.2-jdk15.jar
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一、从Object到String
要先用Object对象构造一个JSONObject或者JSONArray对象，然后调用它的toString()方法即可
（1）示例一
Book book=new Book();book.setName("Java");book.setPrice(52.3f);JSONObject object=JSONObject.fromObject(book);System.out.println(object.toString());（2）示例二
Book book=new Book();book.setName("Java");book.setPrice(52.3f); ???????Book book2=new Book();book2.setName("C");book2.setPrice(42.3f);List list=new ArrayList();list.add(book);list.add(book2);JSONArray arry=JSONArray.fromObject(list);System.out.println(arry.toString());//结果如下：[{"name":"Java","price":52.3},{"name":"C","price":42.3}]二、从String到Object
要先用String对象构造一个JSONObject或者JSONArray对象
（1）示例一
String json="{name:‘Java‘,price:52.3}"; ???JSONObject object=JSONObject.fromObject(json);System.out.println(object.get("name")+" "+object.get("price"));（2）示例二
String json="[{name:‘Java‘,price:52.3},{name:‘C‘,price:42.3}]";JSONArray array=JSONArray.fromObject(json);for(int i=0;i<array.size();i++){ ???Map o=(Map)array.get(i); ???System.out.println(o.get("name")+" "+o.get("price"));}三、从String到Bean
（1）单个Bean对象
String json="{name:‘Java‘,price:52.3}";JSONObject object=JSONObject.fromObject(json);Product product=(Product)JSONObject.toBean(object,Product.class);System.out.println(product.getName()+" "+product.getPrice());（2）Bean的数组
String json="[{name:‘Java‘,price:52.3},{name:‘C‘,price:42.3}]";JSONArray array=JSONArray.fromObject(json);Product[] products=(Product[]) JSONArray.toArray(array,Product.class);for(Product p:products){ ??????System.out.println(p.getName()+" "+p.getPrice()); }三、自定义封装JSON操作的类
package com.util;import java.util.List;import java.util.Map;import net.sf.json.JSONArray;import net.sf.json.JSONObject;public class JsonHelper { ???//从普通的Bean转换为字符串 ???public static String getJson(Object o){ ???????JSONObject jo=JSONObject.fromObject(o); ???????return jo.toString(); ???} ???//从Java的列表转换为字符串 ???public static String getJson(List list){ ???????JSONArray ja=JSONArray.fromObject(list); ???????return ja.toString(); ???} ???//从Java对象数组转换为字符串 ???public static String getJson(Object[] arry){ ???????JSONArray ja=JSONArray.fromObject(arry); ???????return ja.toString(); ???} ???//从json格式的字符串转换为Map对象 ???public static Map getObject(String s){ ???????return ????JSONObject.fromObject(s); ???} ???//从json格式的字符串转换为List数组 ???public static List getArray(String s){ ???????return JSONArray.fromObject(s); ???} ???//从json格式的字符串转换为某个Bean ???public static Object getObject(String s,Class cls){ ???????JSONObject jo=JSONObject.fromObject(s); ???????return JSONObject.toBean(jo, cls); ???} ???//从json格式的字符串转换为某类对象的数组 ???public static Object getArray(String s,Class cls){ ???????JSONArray ja=JSONArray.fromObject(s); ???????return JSONArray.toArray(ja, cls); ???}}json-lib使用——JSONObject与JSONArray
原文地址：https://www.cnblogs.com/javahr/p/8278474.html