标签:sbo headers encoder arch bcd sts 索引 ide 插件
一、简介
org.json是Java常用的Json解析工具,主要提供JSONObject和JSONArray类,现在就各个类的使用解释如下。
二、准备
1.在使用org.json之前,我们应该先从该网址https://github.com/douglascrockford/JSON-java下载org.json源码,并将源码其加入到Eclipse中,即可调用。
2.查看相关的API文档,访问:https://github.com/douglascrockford/JSON-java。
https://github.com/stleary/JSON-Java-unit-test
三、讲解:
1.JSONObject:
是一个无序的键/值对集合。
它的表现形式是一个包裹在花括号的字符串,键和值之间使用冒号隔开,键值和键值之间使用逗号隔开。
内在形式是一个使用get()和opt()方法通过键来访问值,和使用put()方法通过键来添加或者替代值的对象。
值可以是任何这些类型:Boolean,JSONArray,JSONObject,Number和String,或者JOSONObject.NULL对象。
代码演示如下:
注:JSONObject有很多optXXX方法,比如optBoolean, optString, optInt...
他们的意思是,如果这个jsonObject有这个属性,则返回这个属性,否则返回一个默认值。
2.JSONArray:
是一个有序的序列值。
它的表现形式是一个包裹在方括号的字符串,值和值之间使用逗号隔开。
内在形式是一个使用get()和opt()方法通过索引来访问值,和使用put()方法来添加或修改值的对象。
值可以是任何这些类型:Boolean,JSONArray,JSONObject,Number,和String,或者JSONObject.NULL对象。
代码演示如下:
嵌套的JSONObject和JSONArray代码演示如下:
3.JSONStringer:
是一个用于快速构造JSON文本的工具
JSONWriter的子类
bject():开始一个对象,即添加{;enObject():结束一个对象,即添加}
array():开始一个数组,即添加[; endArray():结束一个数组,即添加]
key():表示添加一个key;value():表示添加一个value
代码演示如下:
负载的JSON格式写演示(PrintWriter+JSONStringer可以写入JSON文件):
4.JSONTokener
它和JSONObject和JSONArray的构造函数一起使用,用于解析JSON源字符串
代码演示如下(JSONObject+JSONTokener能够获取JSON格式文本对象):
注意:在Java中,JSON格式的字符串最好用单引号表示
JSON in Java [package org.json] JSON is a light-weight, language independent, data interchange format. See http://www.JSON.org/ The files in this package implement JSON encoders/decoders in Java. It also includes the capability to convert between JSON and XML, HTTP headers, Cookies, and CDL. This is a reference implementation. There is a large number of JSON packages in Java. Perhaps someday the Java community will standardize on one. Until then, choose carefully. The license includes this restriction: "The software shall be used for good, not evil." If your conscience cannot live with that, then choose a different package. The package compiles on Java 1.6-1.8. JSONObject.java: The JSONObject can parse text from a String or a JSONTokener to produce a map-like object. The object provides methods for manipulating its contents, and for producing a JSON compliant object serialization. JSONArray.java: The JSONObject can parse text from a String or a JSONTokener to produce a vector-like object. The object provides methods for manipulating its contents, and for producing a JSON compliant array serialization. JSONTokener.java: The JSONTokener breaks a text into a sequence of individual tokens. It can be constructed from a String, Reader, or InputStream. JSONException.java: The JSONException is the standard exception type thrown by this package. JSONPointer.java: Implementation of [JSON Pointer (RFC 6901)](https://tools.ietf.org/html/rfc6901). Supports JSON Pointers both in the form of string representation and URI fragment representation. JSONString.java: The JSONString interface requires a toJSONString method, allowing an object to provide its own serialization. JSONStringer.java: The JSONStringer provides a convenient facility for building JSON strings. JSONWriter.java: The JSONWriter provides a convenient facility for building JSON text through a writer. CDL.java: CDL provides support for converting between JSON and comma delimited lists. Cookie.java: Cookie provides support for converting between JSON and cookies. CookieList.java: CookieList provides support for converting between JSON and cookie lists. HTTP.java: HTTP provides support for converting between JSON and HTTP headers. HTTPTokener.java: HTTPTokener extends JSONTokener for parsing HTTP headers. XML.java: XML provides support for converting between JSON and XML. JSONML.java: JSONML provides support for converting between JSONML and XML. XMLTokener.java: XMLTokener extends JSONTokener for parsing XML text. Unit tests are maintained in a separate project. Contributing developers can test JSON-java pull requests with the code in this project: https://github.com/stleary/JSON-Java-unit-test
package com.json; import java.text.ParseException; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; /** * 使用json-lib构造和解析Json数据 * * @author Alexia * @date 2013/5/23 * */ public class OrgJsonTest { /** * 构造Json数据 * * @return * @throws JSONException */ public static String BuildJson() throws JSONException { // JSON格式数据解析对象 JSONObject jo = new JSONObject(); // 下面构造两个map、一个list和一个Employee对象 Map<String, String> map1 = new HashMap<String, String>(); map1.put("name", "Alexia"); map1.put("sex", "female"); map1.put("age", "23"); Map<String, String> map2 = new HashMap<String, String>(); map2.put("name", "Edward"); map2.put("sex", "male"); map2.put("age", "24"); List<Map> list = new ArrayList<Map>(); list.add(map1); list.add(map2); Employee employee = new Employee(); employee.setName("wjl"); employee.setSex("female"); employee.setAge(24); // 将Map转换为JSONArray数据 JSONArray ja = new JSONArray(); ja.put(map1); System.out.println("JSONArray对象数据格式:"); System.out.println(ja.toString()); // 将Javabean转换为Json数据(需要Map中转) JSONObject jo1 = JsonHelper.toJSON(employee); System.out.println("\n仅含Employee对象的Json数据格式:"); System.out.println(jo1.toString()); // 构造Json数据,包括一个map和一个含Employee对象的Json数据 jo.put("map", ja); jo.put("employee", jo1.toString()); System.out.println("\n最终构造的JSON数据格式:"); System.out.println(jo.toString()); return jo.toString(); } /** * 解析Json数据 * * @param jsonString * Json数据字符串 * @throws JSONException * @throws ParseException */ public static void ParseJson(String jsonString) throws JSONException, ParseException { JSONObject jo = new JSONObject(jsonString); JSONArray ja = jo.getJSONArray("map"); System.out.println("\n将Json数据解析为Map:"); System.out.println("name: " + ja.getJSONObject(0).getString("name") + " sex: " + ja.getJSONObject(0).getString("sex") + " age: " + ja.getJSONObject(0).getInt("age")); String jsonStr = jo.getString("employee"); Employee emp = new Employee(); JsonHelper.toJavaBean(emp, jsonStr); System.out.println("\n将Json数据解析为Employee对象:"); System.out.println("name: " + emp.getName() + " sex: " + emp.getSex() + " age: " + emp.getAge()); } /** * @param args * @throws JSONException * @throws ParseException */ public static void main(String[] args) throws JSONException, ParseException { // TODO Auto-generated method stub ParseJson(BuildJson()); } }
运行结果如下
json-lib和org.json的使用几乎是相同的,我总结出的区别有两点:
1. org.json比json-lib要轻量得多,前者没有依赖任何其他jar包,而后者要依赖ezmorph和commons的lang、logging、beanutils、collections等组件
2. json-lib在构造bean和解析bean时比org.json要方便的多,json-lib可直接与bean互相转换,而org.json不能直接与bean相互转换而需要map作为中转,若将bean转为json数据,首先需要先将bean转换为map再将map转为json,比较麻烦。
总之,还是那句话—适合自己的才是最好的,大家要按需选取使用哪种方法进行解析。最后给大家介绍两款解析Json数据的工具:一是在线工具JSON Edit(http://braincast.nl/samples/jsoneditor/);另一个是Eclipse的插件JSON Tree Analyzer,都很好用,推荐给大家使用!
http://www.cnblogs.com/lanxuezaipiao/archive/2013/05/24/3096437.html
标签:sbo headers encoder arch bcd sts 索引 ide 插件
原文地址:http://www.cnblogs.com/softidea/p/6102715.html