本文将会以从聚合网获得数据为例,介绍如何在Android Studio中获取JSON并解析
这里做一个简单的天气查询的应用
文章目录
- 1. 准备工作--导入依赖
- 2. 核心代码部分
- 2.1 Get方式的http请求
- 2.2 写出查询函数,包含解析
- 2.3 写好显示内容的textView和button
- 5. 添加权限
- 6. 最后一点小问题
- 7. 运行结果
1. 准备工作–导入依赖
JSON解析这里会用到net.sf.json.JSONObject
正常的Android studio会报错,这里需要导入几个jar包
一般情况下,去搜索json-lib-2.4-jdk15.jar就可以找到跟它相关的所有包,如下:
接下来导入app->libs中
这里面会有包跟默认的冲突,所以需要手动删除这个文件:
commons-beanutils -> org -> apache -> commons 下的collections文件夹
2. 核心代码部分
2.1 Get方式的http请求
在开始写代码之前,需要先获取聚合网的API_KEY
这里与http连接,和JSON解析,都参考了聚合网的查询接口
// 天气情况查询接口地址
public static String API_URL = "http://apis.juhe.cn/simpleWeather/query";
// 接口请求Key,这里需要输入自己的API_KEY
public static String API_KEY = "xxxxxxxxxxxxxx";
/**
* get方式的http请求
*
* @param httpUrl 请求地址
* @return 返回结果
*/
public static String doGet(String httpUrl, String queryParams) {
HttpURLConnection connection = null;
InputStream inputStream = null;
BufferedReader bufferedReader = null;
String result = null;// 返回结果字符串
try {
// 创建远程url连接对象
URL url = new URL(new StringBuffer(httpUrl).append("?").append(queryParams).toString());
// 通过远程url连接对象打开一个连接,强转成httpURLConnection类
connection = (HttpURLConnection) url.openConnection();
// 设置连接方式:get
connection.setRequestMethod("GET");
// 设置连接主机服务器的超时时间:15000毫秒
connection.setConnectTimeout(5000);
// 设置读取远程返回的数据时间:60000毫秒
connection.setReadTimeout(6000);
// 发送请求
connection.connect();
// 通过connection连接,获取输入流
if (connection.getResponseCode() == 200) {
inputStream = connection.getInputStream();
// 封装输入流,并指定字符集
bufferedReader = new BufferedReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8));
// 存放数据
StringBuilder sbf = new StringBuilder();
String temp;
while ((temp = bufferedReader.readLine()) != null) {
sbf.append(temp);
sbf.append(System.getProperty("line.separator"));
}
result = sbf.toString();
}
} catch (IOException e) {
e.printStackTrace();
} finally {
// 关闭资源
if (null != bufferedReader) {
try {
bufferedReader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (null != inputStream) {
try {
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (connection != null) {
connection.disconnect();// 关闭远程连接
}
}
return result;
}
2.2 写出查询函数,包含解析
先查询JSON返回示例:
{
"reason": "查询成功",
"result": {
"city": "苏州",
"realtime": {
"temperature": "4",
"humidity": "82",
"info": "阴",
"wid": "02",
"direct": "西北风",
"power": "3级",
"aqi": "80"
},
"future": [
{
"date": "2019-02-22",
"temperature": "1/7℃",
"weather": "小雨转多云",
"wid": {
"day": "07",
"night": "01"
},
"direct": "北风转西北风"
},
{
"date": "2019-02-23",
"temperature": "2/11℃",
"weather": "多云转阴",
"wid": {
"day": "01",
"night": "02"
},
"direct": "北风转东北风"
},
{
"date": "2019-02-24",
"temperature": "6/12℃",
"weather": "多云",
"wid": {
"day": "01",
"night": "01"
},
"direct": "东北风转北风"
},
{
"date": "2019-02-25",
"temperature": "5/12℃",
"weather": "小雨转多云",
"wid": {
"day": "07",
"night": "01"
},
"direct": "东北风"
},
{
"date": "2019-02-26",
"temperature": "5/11℃",
"weather": "多云转小雨",
"wid": {
"day": "01",
"night": "07"
},
"direct": "东北风"
}
]
},
"error_code": 0
}
JAVA代码:
/**
* 根据城市名查询天气情况
*
* @param cityName
*/
public static void queryWeather(String cityName) {
Map<String, Object> params = new HashMap<>();//组合参数
params.put("city", cityName);
params.put("key", API_KEY);
String queryParams = urlencode(params);
String response = doGet(API_URL, queryParams);
try {
JSONObject jsonObject = JSONObject.fromObject(response);
int error_code = jsonObject.getInt("error_code");
if (error_code == 0) {
System.out.println("调用接口成功");
JSONObject result = jsonObject.getJSONObject("result");
JSONObject realtime = result.getJSONObject("realtime");
rcvString="";
rcvString+=("\n城市:"+ result.getString("city"));
rcvString+=("\n天气:"+ realtime.getString("info"));
rcvString+=("\n温度:" +realtime.getString("temperature"));
rcvString+=("\n湿度:"+ realtime.getString("humidity"));
rcvString+=("\n风向:"+ realtime.getString("direct"));
rcvString+=("\n风力:"+ realtime.getString("power"));
rcvString+=("\n空气质量:"+ realtime.getString("aqi"));
} else {
Log.d("调用接口失败:" , jsonObject.getString("reason"));
}
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 将map型转为请求参数型
*
* @param data
* @return
*/
public static String urlencode(Map<String, ?> data) {
StringBuilder sb = new StringBuilder();
for (Map.Entry<String, ?> i : data.entrySet()) {
try {
sb.append(i.getKey()).append("=").append(URLEncoder.encode(i.getValue() + "", "UTF-8")).append("&");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
String result = sb.toString();
result = result.substring(0, result.lastIndexOf("&"));
return result;
}
2.3 写好显示内容的textView和button
TextView textView,inputText;
Button msgBtn;
public static String rcvString = "";
textView = findViewById(R.id.textView);
msgBtn = findViewById(R.id.button);
inputText = findViewById(R.id.editTextTextPersonName);
msgBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String cityName = inputText.getText().toString();
queryWeather(cityName);
textView.setText(rcvString);
}
});
5. 添加权限
在AndroidManifest.xml文件中添加:
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
android:usesCleartextTraffic="true"
6. 最后一点小问题
由于传输的数据量可能不小,所以需要在oncreate下面加这么一句话:
if (android.os.Build.VERSION.SDK_INT > 9) {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
}
7. 运行结果