BAEL-1555 (#4652)

* BAEL-1555

* Corrected indents and spacing

* RequestMapping to GetMapping

spring-5-mvc/src/main/java/com/baeldung/Constants.java

@@ -0,0 +1,21 @@
+package com.baeldung;
+
+public class Constants {
+
+    public static final String GENERIC_EXCEPTION = "Exception encountered!";
+
+    /**
+     * API endpoints.
+     */
+    public static final String API_RBE = "/rbe";
+    public static final String API_SSE = "/sse";
+    public static final String API_SRB = "/srb";
+
+    /**
+     * API Responses.
+     */
+    public static final String API_RBE_MSG = "I Was Sent From a Response Body Emitter!";
+    public static final String API_SSE_MSG = "I Was Sent From a Sse!";
+    public static final String API_SRB_MSG = "I Was Sent From a Streaming Response Body!";
+
+}

spring-5-mvc/src/main/java/com/baeldung/model/Foo.java

@@ -49,8 +49,6 @@ public class Foo {
         this.name = name;
     }
 
-    //
-
     @Override
     public int hashCode() {
         final int prime = 31;

spring-5-mvc/src/main/java/com/baeldung/persistence/DataSetupBean.java

@@ -16,8 +16,6 @@ public class DataSetupBean implements InitializingBean {
     @Autowired
     private FooRepository repo;
 
-    //
-
     @Override
     public void afterPropertiesSet() throws Exception {
         IntStream.range(1, 5).forEach(i -> repo.save(new Foo(randomAlphabetic(8))));

spring-5-mvc/src/main/java/com/baeldung/web/ResponseBodyEmitterController.java

@@ -0,0 +1,35 @@
+package com.baeldung.web;
+
+import com.baeldung.Constants;
+import java.util.Date;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyEmitter;
+
+@Controller
+public class ResponseBodyEmitterController {
+
+    @GetMapping(Constants.API_RBE)
+    public ResponseEntity<ResponseBodyEmitter> handleRbe() {
+        ResponseBodyEmitter emitter = new ResponseBodyEmitter();
+        ExecutorService nonBlockingService = Executors.newSingleThreadExecutor();
+
+            nonBlockingService.execute(() -> {
+                try {
+                    emitter.send(Constants.API_RBE_MSG + " @ " + new Date(), MediaType.TEXT_PLAIN);
+                    emitter.complete();
+                } catch (Exception ex) {
+                      System.out.println(Constants.GENERIC_EXCEPTION);
+                      emitter.completeWithError(ex);
+                }
+            });
+
+            return new ResponseEntity(emitter, HttpStatus.OK);
+        }
+
+}

spring-5-mvc/src/main/java/com/baeldung/web/SseEmitterController.java

@@ -0,0 +1,32 @@
+package com.baeldung.web;
+
+import com.baeldung.Constants;
+import java.util.Date;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
+
+@Controller
+public class SseEmitterController {
+
+    @GetMapping(Constants.API_SSE)
+    public SseEmitter handleSse() {
+        SseEmitter emitter = new SseEmitter();
+
+        ExecutorService nonBlockingService = Executors.newSingleThreadExecutor();
+        nonBlockingService.execute(() -> {
+            try {
+                emitter.send(Constants.API_SSE_MSG + " @ " + new Date());
+                emitter.complete();
+            } catch (Exception ex) {
+                System.out.println(Constants.GENERIC_EXCEPTION);
+                emitter.completeWithError(ex);
+            }
+        });
+
+        return emitter;
+    }
+
+}

spring-5-mvc/src/main/java/com/baeldung/web/StreamingResponseBodyController.java

@@ -0,0 +1,23 @@
+package com.baeldung.web;
+
+import com.baeldung.Constants;
+import java.util.Date;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.servlet.mvc.method.annotation.StreamingResponseBody;
+
+@Controller
+public class StreamingResponseBodyController {
+
+    @GetMapping(Constants.API_SRB)
+    public ResponseEntity<StreamingResponseBody> handleRbe() {
+        StreamingResponseBody stream = out -> {
+            String msg = Constants.API_SRB_MSG + " @ " + new Date();
+            out.write(msg.getBytes());
+        };
+        return new ResponseEntity(stream, HttpStatus.OK);
+      }
+
+}

spring-5-mvc/src/main/webapp/WEB-INF/jsp/index.jsp

@@ -0,0 +1,86 @@
+<%@taglib uri="http://www.springframework.org/tags" prefix="spring" %>
+<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form" %>
+<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
+<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1" %>
+
+<c:set var="ctx" value="${pageContext.request.contextPath}"/>
+
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <title>Spring MVC Async</title>
+    <link href="<c:url value="/resources/styles/style.css"/>" rel="stylesheet">
+</head>
+<body>
+<main>
+    <h2>Spring MVC Async</h2>
+    <div id="rbe"></div>
+    <div id="sse"></div>
+    <div id="srb"></div>
+</main>
+</body>
+<script>
+
+  /**
+   * AJAX Helpers.
+   */
+
+  var xhr = function(url) {
+    return new Promise(function(resolve, reject) {
+      try {
+        var xmhr = new XMLHttpRequest();
+
+        //Listen for API Response
+        xmhr.onreadystatechange = function() {
+          if (xmhr.readyState == XMLHttpRequest.DONE && xmhr.status == 200) return resolve(xmhr.responseText);
+        };
+
+        //Open connection
+        xmhr.open("GET", url, true);
+        //Additional headers as needed
+        //x.withCredentials = true;
+        //x.setRequestHeader("Accept", "application/json");
+        //x.setRequestHeader("Content-Type", "text/plain");
+
+        //Perform the actual AJAX call
+        xmhr.send();
+
+      } catch (ex) {
+        reject("Exception: Oh CORS's you've made a mistake!");
+      }
+    });
+  };
+
+  /**
+   * RBE
+   */
+
+  xhr('http://localhost:8080/rbe').then(function(success){
+    var el = document.getElementById('rbe');
+    el.appendChild(document.createTextNode(success));
+    el.appendChild(document.createElement('br'))
+  });
+
+  /**
+   * SSE
+   */
+
+  var sse = new EventSource('http://localhost:8080/sse');
+  sse.onmessage = function (evt) {
+    var el = document.getElementById('sse');
+    el.appendChild(document.createTextNode(evt.data));
+    el.appendChild(document.createElement('br'))
+  };
+
+  /**
+   * SRB
+   */
+
+  xhr('http://localhost:8080/srb').then(function(success){
+    var el = document.getElementById('srb');
+    el.appendChild(document.createTextNode(success));
+    el.appendChild(document.createElement('br'))
+  });
+
+</script>
+</html>