检查 HTTP 响应代码

heyblood · Jan 23, 2021 · f095676 · f095676
1 parent 4326db4
commit f095676
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Showing 2 changed files with 27 additions and 4 deletions.
diff --git a/.idea/gradle.xml b/.idea/gradle.xml
diff --git a/app/src/main/java/com/example/soonami/MainActivity.java b/app/src/main/java/com/example/soonami/MainActivity.java
@@ -17,6 +17,7 @@
 
 import android.os.AsyncTask;
 import android.os.Bundle;
+import android.text.TextUtils;
 import android.util.Log;
 import android.widget.TextView;
 
@@ -41,12 +42,16 @@
  */
 public class MainActivity extends AppCompatActivity {
 
-    /** Tag for the log messages */
+    /**
+     * Tag for the log messages
+     */
     public static final String LOG_TAG = MainActivity.class.getSimpleName();
 
-    /** URL to query the USGS dataset for earthquake information */
+    /**
+     * URL to query the USGS dataset for earthquake information
+     */
     private static final String USGS_REQUEST_URL =
-            "https://earthquake.usgs.gov/fdsnws/event/1/query?format=geojson&starttime=2014-01-01&endtime=2014-12-01&minmagnitude=7";
+            "https://earthquake.usgs.gov/fdsnws/event/1/query?format=geojson&starttime=2014-01-01&endtime=2014-01-02asdfasdf";
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -155,6 +160,12 @@ private URL createUrl(String stringUrl) {
          */
         private String makeHttpRequest(URL url) throws IOException {
             String jsonResponse = "";
+
+            // If the URL is null, then return early.
+            if (url == null) {
+                return jsonResponse;
+            }
+
             HttpURLConnection urlConnection = null;
             InputStream inputStream = null;
             try {
@@ -164,7 +175,13 @@ private String makeHttpRequest(URL url) throws IOException {
                 urlConnection.setConnectTimeout(15000 /* milliseconds */);
                 urlConnection.connect();
                 inputStream = urlConnection.getInputStream();
-                jsonResponse = readFromStream(inputStream);
+
+                // If the request was successful (response code 200),
+                // then read the input stream and parse the response.
+                if (urlConnection.getResponseCode() == 200) {
+                    inputStream = urlConnection.getInputStream();
+                    jsonResponse = readFromStream(inputStream);
+                }
             } catch (IOException e) {
                 // TODO: Handle the exception
             } finally {
@@ -202,6 +219,11 @@ private String readFromStream(InputStream inputStream) throws IOException {
          * about the first earthquake from the input earthquakeJSON string.
          */
         private Event extractFeatureFromJson(String earthquakeJSON) {
+            // If the JSON string is empty or null, then return early.
+            if (TextUtils.isEmpty(earthquakeJSON)) {
+                return null;
+            }
+
             try {
                 JSONObject baseJsonResponse = new JSONObject(earthquakeJSON);
                 JSONArray featureArray = baseJsonResponse.getJSONArray("features");