{"reason":"查询成功!","result":{"city":"苏州","realtime":{"temperature":"17","humidity":"69","info":"阴","wid":"02","direct":"东风","power":"2级","aqi":"30"},"future":[{"date":"2021-10-25","temperature":"12/21℃","weather":"多云","wid":{"day":"01","night":"01"},"direct":"东风"},{"date":"2021-10-26","temperature":"13/21℃","weather":"多云","wid":{"day":"01","night":"01"},"direct":"东风转东北风"},{"date":"2021-10-27","temperature":"13/22℃","weather":"多云","wid":{"day":"01","night":"01"},"direct":"东北风"},{"date":"2021-10-28","temperature":"13/21℃","weather":"多云转晴","wid":{"day":"01","night":"00"},"direct":"东北风"},{"date":"2021-10-29","temperature":"14/21℃","weather":"多云转小雨","wid":{"day":"01","night":"07"},"direct":"东北风"}]},"error_code":0}
当需要解析复杂的JSON时
第一步，我们先将复杂的JSON进行可视化的转换。
我使用的网站：http://www.esjson.com
第二步，通过视图了解复杂JSON的结构关系，并对其进行有效的解析。
下面我们分别基于GSON、alibaba.fastjson两种不同的Jar包对其进行解析。
代码一：Root.class通过http://www.esjson.com将复杂JSON生成JAVA实体类，再通过GSON提供的fromJson方法转换。
//1. 创建Gson对象
Gson g = new Gson();
//2. 转换 : {"reason":"查询成功!","result":{"city":"苏州","realtime":{"temperature":"17","humidity":"69","info":"阴","wid":"02","direct":"东风","power":"2级","aqi":"30"},"future":[{"date":"2021-10-25","temperature":"12/21℃","weather":"多云","wid":{"day":"01","night":"01"},"direct":"东风"},{"date":"2021-10-26","temperature":"13/21℃","weather":"多云","wid":{"day":"01","night":"01"},"direct":"东风转东北风"},{"date":"2021-10-27","temperature":"13/22℃","weather":"多云","wid":{"day":"01","night":"01"},"direct":"东北风"},{"date":"2021-10-28","temperature":"13/21℃","weather":"多云转晴","wid":{"day":"01","night":"00"},"direct":"东北风"},{"date":"2021-10-29","temperature":"14/21℃","weather":"多云转小雨","wid":{"day":"01","night":"07"},"direct":"东北风"}]},"error_code":0}
Root r = g.fromJson("{"reason":"查询成功!","result":{"city":"苏州","realtime":{"temperature":"17","humidity":"69","info":"阴","wid":"02","direct":"东风","power":"2级","aqi":"30"},"future":[{"date":"2021-10-25","temperature":"12\/21℃","weather":"多云","wid":{"day":"01","night":"01"},"direct":"东风"},{"date":"2021-10-26","temperature":"13\/21℃","weather":"多云","wid":{"day":"01","night":"01"},"direct":"东风转东北风"},{"date":"2021-10-27","temperature":"13\/22℃","weather":"多云","wid":{"day":"01","night":"01"},"direct":"东北风"},{"date":"2021-10-28","temperature":"13\/21℃","weather":"多云转晴","wid":{"day":"01","night":"00"},"direct":"东北风"},{"date":"2021-10-29","temperature":"14\/21℃","weather":"多云转小雨","wid":{"day":"01","night":"07"},"direct":"东北风"}]},"error_code":0}",Root.class);
if (r.getError_code() == 0 && "查询成功!".equals(r.getReason())) {
System.out.println("调用接口成功");
System.out.println("返回数据，没得问题");
System.out.printf("城市：%s%n", r.getResult().getCity());
System.out.println("今天天气如下");
System.out.printf("天气：%s%n", r.getResult().getRealtime().getInfo());
System.out.printf("温度：%s%n", r.getResult().getRealtime().getTemperature());
System.out.printf("湿度：%s%n", r.getResult().getRealtime().getHumidity());
System.out.printf("风向：%s%n", r.getResult().getRealtime().getDirect());
System.out.printf("风力：%s%n", r.getResult().getRealtime().getPower());
System.out.printf("空气质量：%s%n", r.getResult().getRealtime().getAqi());
for (int i = 0; i < r.getResult().getFuture().size(); i++) {
System.out.printf("日期：%s%n", r.getResult().getFuture().get(i).getDate());
System.out.printf("天气：%s%n", r.getResult().getFuture().get(i).getWeather());
System.out.printf("温度：%s%n", r.getResult().getFuture().get(i).getTemperature());
System.out.printf("风向：%s%n", r.getResult().getFuture().get(i).getDirect());
}
} else
System.out.println("数据有误");
代码二：通过alibaba.fastjson提供的parseObject(String str)将str转化为相应的JSONObject对象。
然后通逐层调用getJSONObject、getJSONArray等等去获取内部对象或者数组。
JSONObject jsonObject =JSONObject.parseObject("{"reason":"查询成功!","result":{"city":"苏州","realtime":{"temperature":"17","humidity":"69","info":"阴","wid":"02","direct":"东风","power":"2级","aqi":"30"},"future":[{"date":"2021-10-25","temperature":"12\/21℃","weather":"多云","wid":{"day":"01","night":"01"},"direct":"东风"},{"date":"2021-10-26","temperature":"13\/21℃","weather":"多云","wid":{"day":"01","night":"01"},"direct":"东风转东北风"},{"date":"2021-10-27","temperature":"13\/22℃","weather":"多云","wid":{"day":"01","night":"01"},"direct":"东北风"},{"date":"2021-10-28","temperature":"13\/21℃","weather":"多云转晴","wid":{"day":"01","night":"00"},"direct":"东北风"},{"date":"2021-10-29","temperature":"14\/21℃","weather":"多云转小雨","wid":{"day":"01","night":"07"},"direct":"东北风"}]},"error_code":0}");
int error_code = jsonObject.getInteger("error_code");
if (error_code == 0 && "查询成功!".equals((String) jsonObject.get("reason"))) {
System.out.println("调用接口成功");
System.out.println("返回数据，没得问题");
JSONObject result = jsonObject.getJSONObject("result");
JSONObject realtime = result.getJSONObject("realtime");
JSONArray future = result.getJSONArray("future");
System.out.printf("城市：%s%n", result.getString("city"));
System.out.println("今天天气如下");
System.out.printf("天气：%s%n", realtime.getString("info"));
System.out.printf("温度：%s%n", realtime.getString("temperature"));
System.out.printf("湿度：%s%n", realtime.getString("humidity"));
System.out.printf("风向：%s%n", realtime.getString("direct"));
System.out.printf("风力：%s%n", realtime.getString("power"));
System.out.printf("空气质量：%s%n", realtime.getString("aqi"));
for (int i = 0; i < future.size(); i++) {
System.out.printf("日期：%s%n", future.getJSONObject(i).getString("date"));
System.out.printf("天气：%s%n", future.getJSONObject(i).getString("weather"));
System.out.printf("温度：%s%n", future.getJSONObject(i).getString("temperature"));
System.out.printf("风向：%s%n", future.getJSONObject(i).getString("direct"));
}
} else
System.out.println("数据有误");
