Java 结合多线程实现简单 HTTP 服务器

本是古典何须时尚 2022-05-13 01:42 236阅读 0赞

能自己实现一个简单的 HTTP 服务器，还有些小激动的。  
本简单 HTTP Server 实现给客户端返回 HTML 文本和二进制文件（图片），  
啥也不说了，直接上码吧：

import java.io.*;
    import java.net.ServerSocket;
    import java.net.Socket;
    import java.util.concurrent.SynchronousQueue;
    import java.util.concurrent.ThreadPoolExecutor;
    import java.util.concurrent.TimeUnit;
    
    class HttpRequestHandler implements Runnable { 
        private Socket socket;
        private String basePath;
    
        public HttpRequestHandler(Socket socket, String basePath) { 
            this.socket = socket;
            this.basePath = basePath;
        }
    
        @Override
        public void run() { 
            String threadName = Thread.currentThread().getName();
            BufferedReader reader = null;
    
            // 向客户端输出内容
            PrintStream printStream = null;
            InputStream in = null;
            BufferedReader br = null;
    
            try { 
                // 在 socket 上获得输入流，使用默认字符集的 InputStreamReader
                reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
    
                // 读取 HTTP 报文的请求行
                String header = reader.readLine();
                System.out.println("thread name: " + threadName + ", HTTP 报文请求行: " + header);
    
                // 读取HTTP请求报文的起始行，并根据空格分割开，存入数组，得到请求的资源
                // 由相对路径计算出绝对路径
                String filePath = this.basePath + header.split(" ")[1];
    
                printStream = new PrintStream(socket.getOutputStream(), true);
    
                // 如果请求资源的后缀为jpg 或者 ico，则读取资源并输出
                if (filePath.endsWith("jpg") || filePath.endsWith("ico")) { 
                    System.out.println("thread name: " + threadName + ", filePath: " + filePath);
    
                    in = new FileInputStream(filePath);
                    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    
                    byte[] buff = new byte[1024];
                    int i;
                    while ((i = in.read(buff)) != -1) { 
                        baos.write(buff, 0, i);
                    }
                    byte[] array = baos.toByteArray();
    
                    // 设置响应报文
                    printStream.println("HTTP/1.1 200 OK");
                    printStream.println("Server: MyServer");
                    printStream.println("Content-Type: image/jpeg");
                    printStream.println("Content-Length: " + array.length);
                    // 根据 HTTP 协议, 空行将结束头信息
                    printStream.println();
                    printStream.write(array);
                } else if (filePath.endsWith("html")) { 
                    // 客户端请求的是 html 文件
                    br = new BufferedReader(new InputStreamReader(new FileInputStream(filePath)));
                    printStream.println("HTTP/1.1 200 OK");
                    printStream.println("Server: MyServer");
                    printStream.println("Content-Type: text/html; charset=UTF-8");
                    printStream.println();
    
                    String line;
                    while ((line = br.readLine()) != null) { 
                        printStream.println(line);
                    }
                }
                printStream.flush();
            } catch (Exception ex) { 
                ex.printStackTrace();
                printStream.println("HTTP/1.1 500");
                printStream.println();
                printStream.flush();
            } finally { 
                this.close(br, in, reader, socket, printStream);
            }
    
        }
    
        private void close(Closeable... closeables) { 
            if (closeables != null) { 
                for (Closeable closeable : closeables) { 
                    try { 
                        if (closeable != null) { 
                            closeable.close();
                        }
                    } catch (Exception e) { 
    
                    }
                }
            }
    
        }
    }
    
    public class MySimpleHttpServer { 
    
        // 处理 HttpRequest 的线程池
        private static ThreadPoolExecutor executor = new ThreadPoolExecutor(5, 10, 60L, TimeUnit.SECONDS, new SynchronousQueue<>());
    
        /** * SimpleHttpServer 的根路径 */
        private String basePath;
    
        /** * 服务监听端口 */
        private int port = 8080;
    
        public void start() throws Exception { 
            System.out.println("start at " + port + ", basePath: " + this.basePath);
    
            // serverSocket 接受客户端的请求
            ServerSocket serverSocket = new ServerSocket(port);
            Socket socket;
            /** * 服务端 serverSocket 接受客户端请求，并创建客户端 socket 对象 */
            while ((socket = serverSocket.accept()) != null) { 
                /** * 接收一个客户端Socket，生成一个HttpRequestHandler，放入线程池队列 */
                executor.execute(new HttpRequestHandler(socket, this.basePath));
            }
            serverSocket.close();
        }
    
        public void setBasePath(String basePath) { 
            if (basePath != null && new File(basePath).exists() &&
                    new File(basePath).isDirectory()) { 
                this.basePath = basePath;
            }
        }
    
        public void setPort(int port) { 
            if (port > 0) { 
                this.port = port;
            }
        }
    }

运行server：

public class ServerStart { 
        public static void main(String[] args) throws Exception { 
            MySimpleHttpServer httpServer = new MySimpleHttpServer();
            httpServer.setBasePath("/data/simpleHttpServer");
            httpServer.start();
        }
    }

写一个 HTML 页面测试一下吧：

// index.html 
    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="utf-8">
    <link rel=”icon” href=”favicon.ico” mce_href=”favicon.ico” type=”image/x-icon”>
    <title>simple server test</title>
    </head>
    
    <body>
    文档内容......
    <h1>第一张图片</h1>
    <img src="1.jpg" align="middle" />
    <h1>第二张图片</h1>
    <img src="2.jpg" align="middle" />
    <h1>第三张图片</h1>
    <img src="3.jpg" align="middle" />
    
    </body>
    
    </html>

将 `index.html`、`1.jpg`等资源放到`basePath`下，然后在浏览器的地址栏里输入：[http://127.0.0.1:8080/index.html，然后就看到这个奇妙的网页了：][http_127.0.0.1_8080_index.html]  
![这里写图片描述][70]

浏览器并发的请求，因为有了多线程，这个简单的 HTTP Server 的吞吐量也还可以的，响应时间也很小。

参考： [用java实现的一个简单web服务器程序][java_web]  
[java实现简单的http服务器][java_http]  
[HTTP头部详解及使用Java套接字处理HTTP请求][HTTP_Java_HTTP]

[http_127.0.0.1_8080_index.html]: http://127.0.0.1:8080/index.html%EF%BC%8C%E7%84%B6%E5%90%8E%E5%B0%B1%E7%9C%8B%E5%88%B0%E8%BF%99%E4%B8%AA%E5%A5%87%E5%A6%99%E7%9A%84%E7%BD%91%E9%A1%B5%E4%BA%86%EF%BC%9A
[70]: /images/20220513/093f329a001b4903ae31e990122210a9.png
[java_web]: https://blog.csdn.net/lubiaopan/article/details/4913748
[java_http]: http://cugxuan.coding.me/2017/07/20/Java/java%E5%AE%9E%E7%8E%B0%E7%AE%80%E5%8D%95%E7%9A%84http%E6%9C%8D%E5%8A%A1%E5%99%A8/
[HTTP_Java_HTTP]: https://blog.csdn.net/overmaker/article/details/2194921