ps：看这篇博客之前首先要引入工具包json-lib-2.2.2-jdk15.jar
资源链接：百度云：链接：https://pan.baidu.com/s/1o9k7PSu 密码：00lj
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); } }
