人丑话不多：
直接上代码：
1.根据返回的json数据格式定义数据模型
import java.util.List;//定义一个描述天气的类public class WeatherForecastInfo {private Double pm25;private List<Forecast> mForecasts;public Double getPm25() {return pm25;}public void setPm25(Double pm25) {this.pm25 = pm25;}public List<Forecast> getmForecasts() {return mForecasts;}public void setmForecasts(List<Forecast> mForecasts) {this.mForecasts = mForecasts;}@Overridepublic String toString() {return "天气信息[" +"pm25=" + pm25 +", mForecasts=" + mForecasts +']';}//定义一个内部类public static class Forecast{private String date;//时间private String high;//最高温private String low;//最低温private String fx;//风向private String fl;//风等级private String type;//天气类型private String notice;//温馨提示public String getDate() {return date;}public void setDate(String date) {this.date = date;}public String getHigh() {return high;}public void setHigh(String high) {this.high = high;}public String getLow() {return low;}public void setLow(String low) {this.low = low;}public String getFx() {return fx;}public void setFx(String fx) {this.fx = fx;}public String getFl() {return fl;}public void setFl(String fl) {this.fl = fl;}public String getType() {return type;}public void setType(String type) {this.type = type;}public String getNotice() {return notice;}public void setNotice(String notice) {this.notice = notice;}//重写toString方法@Overridepublic String toString() {return "未来天气[" +"日期='" + date + '\'' +", 最高温='" + high + '\'' +", 最低温='" + low + '\'' +", 风向='" + fx + '\'' +", 风等级='" + fl + '\'' +", 天气类型='" + type + '\'' +", 温馨提示='" + notice + '\'' +']';}}}
2.编写Java代码进行json数据获取和解析
import android.os.Bundle;import android.support.annotation.Nullable;import android.support.v7.app.AppCompatActivity;import android.util.Log;import android.view.View;import android.widget.Button;import android.widget.TextView;import org.json.JSONArray;import org.json.JSONException;import org.json.JSONObject;import java.io.BufferedWriter;import java.io.ByteArrayOutputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import java.io.OutputStreamWriter;import java.io.UnsupportedEncodingException;import .HttpURLConnection;import .MalformedURLException;import .URL;import .URLEncoder;import java.util.ArrayList;import java.util.List;public class NetWorkActivity extends AppCompatActivity{private Button btn_getData;private Button btn_parseData;private TextView tv_result;private String result;//创建一个WeatherForecastInfo对象WeatherForecastInfo weatherForecastInfo=new WeatherForecastInfo();//创建一个Forecast集合List<WeatherForecastInfo.Forecast> forecastList=new ArrayList<>();@Overrideprotected void onCreate(@Nullable Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_network);//初始化控件initialView();//添加事件监听myClickListener();}//初始化控件public void initialView(){btn_getData=findViewById(R.id.btn_getData);btn_parseData=findViewById(R.id.btn_parseData);tv_result=findViewById(R.id.tv_result);}class MyOnClickListener implements View.OnClickListener{@Overridepublic void onClick(View view) {switch (view.getId()){case R.id.btn_getData://获取天气的jason数据//1.耗时操作必须放在线程中执行，否则报异常//2.有网络请求的，必须在开启网络权限new Thread(new Runnable() {@Overridepublic void run() {requestDataByGet();}}).start();break;case R.id.btn_parseData://解析天气的jason数据handleJsonData(result);showWeatherInfo(forecastList);break;}}}//json数据解析private void handleJsonData(String result){//创建一个json对象,捕获异常try {JSONObject jsonObject=new JSONObject(result);//提取日期String date=jsonObject.getString("date");System.out.println("date:"+date);//提取城市String city=jsonObject.getString("city");System.out.println("city:"+city);//提取data数据JSONObject dataObject=jsonObject.getJSONObject("data");//提取data里面的pm25double pm25=dataObject.getDouble("pm25");weatherForecastInfo.setPm25(pm25);//提取data里面的未来天气//注意：forecast中的内容带有中括号[]，所以要转化为JSONArray类型的对象JSONArray forecasts=dataObject.getJSONArray("forecast");//对forecast数组判空if (forecasts!=null&&forecasts.length()>0){//for循环来处理for (int index=0;index<forecasts.length();index++){//提取出forecast中每个数组中的内容JSONObject weather=forecasts.getJSONObject(index);String mdate=weather.getString("date");//时间String mhigh=weather.getString("high");//最高温String mlow=weather.getString("low");//最低温String mfx=weather.getString("fx");//风向String mfl=weather.getString("fl");//风等级String mtype=weather.getString("type");//天气类型String mnotice=weather.getString("notice");//温馨提示//创建WeatherForecastInfo中的内部类ForecastWeatherForecastInfo.Forecast forecastItem=new WeatherForecastInfo.Forecast();//设置Forecast中的数据forecastItem.setDate(mdate);forecastItem.setHigh(mhigh);forecastItem.setLow(mlow);forecastItem.setFx(mfx);forecastItem.setFl(mfl);forecastItem.setType(mtype);forecastItem.setNotice(mnotice);//最后将forecastItem添加到forecastList集合中forecastList.add(forecastItem);}weatherForecastInfo.setmForecasts(forecastList);}tv_result.setText(weatherForecastInfo.toString());}catch (JSONException e){e.printStackTrace();}}//显示天气数据public void showWeatherInfo(List<WeatherForecastInfo.Forecast> forecastList){//将forecastList列表中的数据循环输出if (forecastList!=null){System.out.println(forecastList.toString());}}//get方法获取json的天气数据private void requestDataByGet() {try {String citiName="北京";String weather_url="/open/api/weather/json.shtml?city="+getEncodeValue(citiName);URL url=new URL(weather_url);HttpURLConnection connection=(HttpURLConnection) url.openConnection();connection.setConnectTimeout(30*1000);connection.setRequestMethod("GET");connection.setRequestProperty("Content-Type","application/json");connection.setRequestProperty("Charset","UTF-8");connection.setRequestProperty("Accept-Charset","UTF-8");connection.connect();//发起连接//获取状态码int requestCode=connection.getResponseCode();System.out.println(requestCode);//获取返回信息String requestMessage=connection.getResponseMessage();System.out.println(requestMessage);//根据状态码进行处理if (requestCode==HttpURLConnection.HTTP_OK){//1.从connection中获得输入流InputStream inputStream=connection.getInputStream();//2.将输入流转换成字符串result=streamToString(inputStream);//3.更新UI必须在主线程中完成runOnUiThread(new Runnable() {@Overridepublic void run() {tv_result.setText(result);}});}else {Log.e("TAG", "run:error code: "+requestCode+",message:"+requestMessage);}}catch (MalformedURLException e){e.printStackTrace();}catch (IOException e){e.printStackTrace();}}//post方法/*private void requestDataByPost() {try {URL url=new URL("/open/api/weather/json.shtml");HttpURLConnection connection=(HttpURLConnection) url.openConnection();connection.setConnectTimeout(30*1000);connection.setRequestMethod("Post");connection.setRequestProperty("Content-Type","application/json");connection.setRequestProperty("Charset","UTF-8");connection.setRequestProperty("Accept-Charset","UTF-8");connection.setDoOutput(true);connection.setDoInput(true);//是否使用缓存connection.setUseCaches(false);connection.connect();//发起连接String data="city="+getEncodeValue("北京");OutputStream outputStream=connection.getOutputStream();outputStream.write(data.getBytes());outputStream.flush();//最后关闭输入流outputStream.close();//获取状态码int requestCode=connection.getResponseCode();//获取返回信息String requestMessage=connection.getResponseMessage();//根据状态码进行处理if (requestCode==HttpURLConnection.HTTP_OK){//从connection中获得输入流InputStream inputStream=connection.getInputStream();//将输入流转换成字符串result=streamToString(inputStream);//3.更新UI必须在主线程中完成runOnUiThread(new Runnable() {@Overridepublic void run() {tv_result.setText(result);}});}else {Log.e("TAG", "run:error code: "+requestCode+",message:"+requestMessage);}}catch (MalformedURLException e){e.printStackTrace();}catch (IOException e){e.printStackTrace();}}*///将编码转换成UTF编码public String getEncodeValue(String imooc){String encode=null;try {encode= URLEncoder.encode(imooc,"UTF-8");}catch (UnsupportedEncodingException e){e.printStackTrace();}return encode;}public void myClickListener(){MyOnClickListener myOnClickListener=new MyOnClickListener();btn_getData.setOnClickListener(myOnClickListener);btn_parseData.setOnClickListener(myOnClickListener);}//将输入流转换成字符串public String streamToString(InputStream inputStream){try{ByteArrayOutputStream baos=new ByteArrayOutputStream();byte[] buffer=new byte[1024];int len;while ((len=inputStream.read(buffer))!=-1){//byte数组、偏移量、数组长度baos.write(buffer,0,len);}//关闭输出流baos.close();//关闭输入流inputStream.close();//将输出流转换成字节数组byte[] byteArray=baos.toByteArray();//将字节数组转换成字符串,并进行返回return new String(byteArray);}catch (Exception e){Log.e("TAG",e.toString());return null;}}}
运行情况：
09-17 11:34:05.830 3910-3910/com.example.jiaho.http I/System.out: date:0917city:北京09-17 11:34:05.834 3910-3910/com.example.jiaho.http I/System.out: [未来天气[日期='17日星期一', 最高温='高温 27.0℃', 最低温='低温 17.0℃', 风向='北风', 风等级='<3级', 天气类型='多云', 温馨提示='阴晴之间，谨防紫外线侵扰'], 未来天气[日期='18日星期二', 最高温='高温 25.0℃', 最低温='低温 17.0℃', 风向='西南风', 风等级='<3级', 天气类型='阴', 温馨提示='不要被阴云遮挡住好心情'], 未来天气[日期='19日星期三', 最高温='高温 26.0℃', 最低温='低温 19.0℃', 风向='南风', 风等级='<3级', 天气类型='多云', 温馨提示='阴晴之间，谨防紫外线侵扰'], 未来天气[日期='20日星期四', 最高温='高温 29.0℃', 最低温='低温 16.0℃', 风向='西北风', 风等级='<3级', 天气类型='多云', 温馨提示='阴晴之间，谨防紫外线侵扰'], 未来天气[日期='21日星期五', 最高温='高温 24.0℃', 最低温='低温 12.0℃', 风向='西风', 风等级='4-5级', 天气类型='晴', 温馨提示='愿你拥有比阳光明媚的心情']]
