소스 파일 최초 업로드

2024-04-05 10:31:45 +09:00
commit 718e6822af
682 changed files with 90848 additions and 0 deletions
--- a/tomcat/webapps.dist/examples/WEB-INF/classes/nonblocking/ByteCounter.java
+++ b/tomcat/webapps.dist/examples/WEB-INF/classes/nonblocking/ByteCounter.java
@@ -0,0 +1,142 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package nonblocking;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+
+import javax.servlet.AsyncContext;
+import javax.servlet.ReadListener;
+import javax.servlet.ServletException;
+import javax.servlet.ServletInputStream;
+import javax.servlet.ServletOutputStream;
+import javax.servlet.WriteListener;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/**
+ * This doesn't do anything particularly useful - it just counts the total
+ * number of bytes in a request body while demonstrating how to perform
+ * non-blocking reads.
+ */
+public class ByteCounter extends HttpServlet {
+
+    private static final long serialVersionUID = 1L;
+
+    @Override
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
+            throws ServletException, IOException {
+
+        resp.setContentType("text/plain");
+        resp.setCharacterEncoding("UTF-8");
+
+        resp.getWriter().println("Try again using a POST request.");
+    }
+
+    @Override
+    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
+            throws ServletException, IOException {
+
+        resp.setContentType("text/plain");
+        resp.setCharacterEncoding("UTF-8");
+
+        // Non-blocking IO requires async
+        AsyncContext ac = req.startAsync();
+
+        // Use a single listener for read and write. Listeners often need to
+        // share state to coordinate reads and writes and this is much easier as
+        // a single object.
+        @SuppressWarnings("unused")
+        CounterListener listener = new CounterListener(
+                ac, req.getInputStream(), resp.getOutputStream());
+    }
+
+
+    /**
+     * Keep in mind that each call may well be on a different thread to the
+     * previous call. Ensure that changes in values will be visible across
+     * threads. There should only ever be one container thread at a time calling
+     * the listener.
+     */
+    private static class CounterListener implements ReadListener, WriteListener {
+
+        private final AsyncContext ac;
+        private final ServletInputStream sis;
+        private final ServletOutputStream sos;
+
+        private volatile boolean readFinished = false;
+        private volatile long totalBytesRead = 0;
+        private byte[] buffer = new byte[8192];
+
+        private CounterListener(AsyncContext ac, ServletInputStream sis,
+                ServletOutputStream sos) {
+            this.ac = ac;
+            this.sis = sis;
+            this.sos = sos;
+
+            // In Tomcat, the order the listeners are set controls the order
+            // that the first calls are made. In this case, the read listener
+            // will be called before the write listener.
+            sis.setReadListener(this);
+            sos.setWriteListener(this);
+        }
+
+        @Override
+        public void onDataAvailable() throws IOException {
+            int read = 0;
+            // Loop as long as there is data to read. If isReady() returns false
+            // the socket will be added to the poller and onDataAvailable() will
+            // be called again as soon as there is more data to read.
+            while (sis.isReady() && read > -1) {
+                read = sis.read(buffer);
+                if (read > 0) {
+                    totalBytesRead += read;
+                }
+            }
+        }
+
+        @Override
+        public void onAllDataRead() throws IOException {
+            readFinished = true;
+
+            // If sos is not ready to write data, the call to isReady() will
+            // register the socket with the poller which will trigger a call to
+            // onWritePossible() when the socket is ready to have data written
+            // to it.
+            if (sos.isReady()) {
+                onWritePossible();
+            }
+        }
+
+        @Override
+        public void onWritePossible() throws IOException {
+            if (readFinished) {
+                // Must be ready to write data if onWritePossible was called
+                String msg = "Total bytes written = [" + totalBytesRead + "]";
+                sos.write(msg.getBytes(StandardCharsets.UTF_8));
+                ac.complete();
+            }
+        }
+
+        @Override
+        public void onError(Throwable throwable) {
+            // Should probably log the throwable
+            ac.complete();
+        }
+    }
+}