JSONPath 用法

以下是利用JSONPath对JSONObject的操作示例代码：

public static void main(String[] args) {
        JSONObject json=new JSONObject();
        json.put("name","张三");
        json.put("sex","女");
        json.put("address","浙江杭州西湖转塘");
        JSONObject son=new JSONObject();
        son.put("name","小明");
        son.put("sex","男");
        son.put("address","浙江杭州萧山宁围");
        json.put("son",son);
        System.out.println("原先："+json.toJSONString());
        JSONPath.set(json,"$.name","小风");
        System.out.println("现在："+json.toJSONString());
        String name =(String) JSONPath.eval(json, "name");
        System.out.println("name:"+name);
        System.out.println(JSONPath.contains(json,"hhh"));
        Map<String, Object> paths = JSONPath.paths(json);
        System.out.println(paths);
    }

输出结果如下：

原先：{"address":"浙江杭州西湖转塘","son":{"address":"浙江杭州萧山宁围","sex":"男","name":"小明"},"sex":"女","name":"张三"}
现在：{"address":"浙江杭州西湖转塘","son":{"address":"浙江杭州萧山宁围","sex":"男","name":"小明"},"sex":"女","name":"小风"}
name:小风
false
{/son/address=浙江杭州萧山宁围, /sex=女, /name=小风, /son={"address":"浙江杭州萧山宁围","sex":"男","name":"小明"}, /son/sex=男, /address=浙江杭州西湖转塘, /son/name=小明, /={"address":"浙江杭州西湖转塘","son":{"address":"浙江杭州萧山宁围","sex":"男","name":"小明"},"sex":"女","name":"小风"}}

总结常用的几种方法：

public class JSONPath {
     //将对象中的属性与值的对应关系转换成  key=value 形式，key包含对象中的对象的属性，可以递归到最底层，这样可以用以直观的判断一个对象中所有的key=value 并操作
     public static Map<String, Object> paths(Object javaObject, SerializeConfig config) {
        Map<Object, String> values = new IdentityHashMap();
        Map<String, Object> paths = new HashMap();
        paths(values, paths, "/", javaObject, config);
        return paths;
    }          
     //  求值，静态方法
     public static Object eval(Object rootObject, String path);

     // 计算Size，Map非空元素个数，对象非空元素个数，Collection的Size，数组的长度。其他无法求值返回-1
     public static int size(Object rootObject, String path);

     // 是否包含，对象中是否包含该path
     public static boolean contains(Object rootObject, String path) { }

     // 是否包含，path中是否存在指定值，如果是集合或者数组，在集合中查找value是否存在
     public static boolean containsValue(Object rootObject, String path, Object value) { }

     // 修改指定路径的值，如果修改成功，返回true，否则返回false
     public static boolean set(Object rootObject, String path, Object value) {}

     // 在数组或者集合中添加元素
     public static boolean array_add(Object rootObject, String path, Object... values);
}

path格式： $.key.key… $表示从根目录起，如上示例代码中
$.son.address=“浙江杭州萧山宁围” 表示jsonObject对象中son 对象里的address属性