BAEL-2454 Reading the error response and building the full response

BAEL-2454 Add examples for reading response content on failed requests. Add example on how to build full response string.

core-java/src/main/java/com/baeldung/http/FullResponseBuilder.java

@@ -0,0 +1,65 @@
+package com.baeldung.http;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.net.HttpURLConnection;
+import java.util.Iterator;
+import java.util.List;
+
+public class FullResponseBuilder {
+    public static String getFullResponse(HttpURLConnection con) throws IOException {
+        StringBuilder fullResponseBuilder = new StringBuilder();
+
+        fullResponseBuilder.append(con.getResponseCode())
+            .append(" ")
+            .append(con.getResponseMessage())
+            .append("\n");
+
+        con.getHeaderFields()
+            .entrySet()
+            .stream()
+            .filter(entry -> entry.getKey() != null)
+            .forEach(entry -> {
+
+                fullResponseBuilder.append(entry.getKey())
+                    .append(": ");
+
+                List<String> headerValues = entry.getValue();
+                Iterator<String> it = headerValues.iterator();
+                if (it.hasNext()) {
+                    fullResponseBuilder.append(it.next());
+
+                    while (it.hasNext()) {
+                        fullResponseBuilder.append(", ")
+                            .append(it.next());
+                    }
+                }
+
+                fullResponseBuilder.append("\n");
+            });
+
+        Reader streamReader = null;
+
+        if (con.getResponseCode() > 299) {
+            streamReader = new InputStreamReader(con.getErrorStream());
+        } else {
+            streamReader = new InputStreamReader(con.getInputStream());
+        }
+
+        BufferedReader in = new BufferedReader(streamReader);
+        String inputLine;
+        StringBuilder content = new StringBuilder();
+        while ((inputLine = in.readLine()) != null) {
+            content.append(inputLine);
+        }
+
+        in.close();
+
+        fullResponseBuilder.append("Response: ")
+            .append(content);
+
+        return fullResponseBuilder.toString();
+    }
+}

core-java/src/test/java/com/baeldung/http/HttpRequestLiveTest.java

@@ -7,6 +7,7 @@ import java.io.BufferedReader;
 import java.io.DataOutputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.io.Reader;
 import java.net.CookieManager;
 import java.net.HttpCookie;
 import java.net.HttpURLConnection;
@@ -48,7 +49,8 @@ public class HttpRequestLiveTest {
         in.close();
 
         assertEquals("status code incorrect", status, 200);
-        assertTrue("content incorrect", content.toString().contains("Example Domain"));
+        assertTrue("content incorrect", content.toString()
+            .contains("Example Domain"));
     }
 
     @Test
@@ -89,18 +91,24 @@ public class HttpRequestLiveTest {
         Optional<HttpCookie> usernameCookie = null;
         if (cookiesHeader != null) {
             List<HttpCookie> cookies = HttpCookie.parse(cookiesHeader);
-            cookies.forEach(cookie -> cookieManager.getCookieStore().add(null, cookie));
-            usernameCookie = cookies.stream().findAny().filter(cookie -> cookie.getName().equals("username"));
+            cookies.forEach(cookie -> cookieManager.getCookieStore()
+                .add(null, cookie));
+            usernameCookie = cookies.stream()
+                .findAny()
+                .filter(cookie -> cookie.getName()
+                    .equals("username"));
         }
 
         if (usernameCookie == null) {
-            cookieManager.getCookieStore().add(null, new HttpCookie("username", "john"));
+            cookieManager.getCookieStore()
+                .add(null, new HttpCookie("username", "john"));
         }
 
         con.disconnect();
 
         con = (HttpURLConnection) url.openConnection();
-        con.setRequestProperty("Cookie", StringUtils.join(cookieManager.getCookieStore().getCookies(), ";"));
+        con.setRequestProperty("Cookie", StringUtils.join(cookieManager.getCookieStore()
+            .getCookies(), ";"));
 
         int status = con.getResponseCode();
 
@@ -125,4 +133,52 @@ public class HttpRequestLiveTest {
         assertEquals("status code incorrect", con.getResponseCode(), 200);
     }
 
+    @Test
+    public void whenFailedRequest_thenOk() throws IOException {
+        URL url = new URL("http://example.com");
+        HttpURLConnection con = (HttpURLConnection) url.openConnection();
+        con.setRequestMethod("POST");
+
+        con.setConnectTimeout(5000);
+        con.setReadTimeout(5000);
+
+        int status = con.getResponseCode();
+
+        Reader streamReader = null;
+
+        if (status > 299) {
+            streamReader = new InputStreamReader(con.getErrorStream());
+        } else {
+            streamReader = new InputStreamReader(con.getInputStream());
+        }
+
+        BufferedReader in = new BufferedReader(streamReader);
+        String inputLine;
+        StringBuilder content = new StringBuilder();
+        while ((inputLine = in.readLine()) != null) {
+            content.append(inputLine);
+        }
+        in.close();
+
+        assertEquals("status code incorrect", status, 411);
+        assertTrue("error content", content.toString()
+            .contains("411 - Length Required"));
+    }
+
+    @Test
+    public void whenGetRequestFullResponse_thenOk() throws IOException {
+        URL url = new URL("http://example.com");
+        HttpURLConnection con = (HttpURLConnection) url.openConnection();
+        con.setRequestMethod("GET");
+
+        con.setConnectTimeout(5000);
+        con.setReadTimeout(5000);
+
+        String fullResponse = FullResponseBuilder.getFullResponse(con);
+
+        assertEquals("status code incorrect", con.getResponseCode(), 200);
+        assertTrue("header incorrect", fullResponse.contains("Content-Type: text/html; charset=UTF-8"));
+        assertTrue("response incorrect", fullResponse.contains("<!doctype html><html><head>"));
+    }
+
 }