1.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
1 Book book=new Book(); 2 book.setName("Java"); 3 book.setPrice(52.3f); 4 JSONObject object=JSONObject.fromObject(book); 5 System.out.println(object.toString());
(2)示例二
1 Book book=new Book(); 2 book.setName("Java"); 3 book.setPrice(52.3f); 4 5 Book book2=new Book(); 6 book2.setName("C"); 7 book2.setPrice(42.3f); 8 List list=new ArrayList(); 9 list.add(book); 10 list.add(book2); 11 JSONArray arry=JSONArray.fromObject(list); 12 System.out.println(arry.toString()); 13 //结果如下: 14 [{"name":"Java","price":52.3},{"name":"C","price":42.3}]
2.从String到Object
要先用String对象构造一个JSONObject或者JSONArray对象
(1)示例一
1 String json="{name:'Java',price:52.3}"; 2 JSONObject object=JSONObject.fromObject(json); 3 System.out.println(object.get("name")+" "+object.get("price"));
(2)示例二
1 String json="[{name:'Java',price:52.3},{name:'C',price:42.3}]"; 2 JSONArray array=JSONArray.fromObject(json); 3 for(int i=0;i<array.size();i++){ 4 Map o=(Map)array.get(i); 5 System.out.println(o.get("name")+" "+o.get("price")); 6 }
3.从String到Bean
(1)单个Bean对象
1 String json="{name:'Java',price:52.3}"; 2 JSONObject object=JSONObject.fromObject(json); 3 Product product=(Product)JSONObject.toBean(object,Product.class); 4 System.out.println(product.getName()+" "+product.getPrice());
(2).Bean的数组
1 String json="[{name:'Java',price:42.3}]"; 2 JSONArray array=JSONArray.fromObject(json); 3 Product[] products=(Product[]) JSONArray.toArray(array,Product.class); 4 for(Product p:products){ 5 System.out.println(p.getName()+" "+p.getPrice()); 6 }
自定义封装JSON操作的类
1 package com.util; 2 3 import java.util.List; 4 import java.util.Map; 5 6 import net.sf.json.JSONArray; 7 import net.sf.json.JSONObject; 8 9 public class JsonHelper { 10 //从普通的Bean转换为字符串 11 public static String getJson(Object o){ 12 JSONObject jo=JSONObject.fromObject(o); 13 return jo.toString(); 14 } 15 //从Java的列表转换为字符串 16 public static String getJson(List list){ 17 JSONArray ja=JSONArray.fromObject(list); 18 return ja.toString(); 19 } 20 //从Java对象数组转换为字符串 21 public static String getJson(Object[] arry){ 22 JSONArray ja=JSONArray.fromObject(arry); 23 return ja.toString(); 24 } 25 //从json格式的字符串转换为Map对象 26 public static Map getObject(String s){ 27 return JSONObject.fromObject(s); 28 } 29 //从json格式的字符串转换为List数组 30 public static List getArray(String s){ 31 return JSONArray.fromObject(s); 32 } 33 //从json格式的字符串转换为某个Bean 34 public static Object getObject(String s,Class cls){ 35 JSONObject jo=JSONObject.fromObject(s); 36 return JSONObject.toBean(jo,cls); 37 } 38 //从json格式的字符串转换为某类对象的数组 39 public static Object getArray(String s,Class cls){ 40 JSONArray ja=JSONArray.fromObject(s); 41 return JSONArray.toArray(ja,cls); 42 } 43 }