是否有一种方法可以使用Java SE API在Java中创建一个非常基本的HTTP服务器(只支持GET/POST),而不需要编写代码手动解析HTTP请求和手动格式化HTTP响应?Java SE API在HttpURLConnection中很好地封装了HTTP客户机功能,但是是否有类似的HTTP服务器功能呢?
需要明确的是,我在网上看到的许多ServerSocket示例的问题是,它们自己进行请求解析/响应格式化和错误处理,这很乏味,容易出错,而且不太全面,出于这些原因,我试图避免使用它。
是否有一种方法可以使用Java SE API在Java中创建一个非常基本的HTTP服务器(只支持GET/POST),而不需要编写代码手动解析HTTP请求和手动格式化HTTP响应?Java SE API在HttpURLConnection中很好地封装了HTTP客户机功能,但是是否有类似的HTTP服务器功能呢?
需要明确的是,我在网上看到的许多ServerSocket示例的问题是,它们自己进行请求解析/响应格式化和错误处理,这很乏味,容易出错,而且不太全面,出于这些原因,我试图避免使用它。
当前回答
Spark是最简单的,这里有一个快速入门指南:http://sparkjava.com/
其他回答
这个代码比我们的代码更好,你只需要添加2个库:javax. servlet .jar和org.mortbay.jetty.jar。
类码头:
package jetty;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.mortbay.http.SocketListener;
import org.mortbay.jetty.Server;
import org.mortbay.jetty.servlet.ServletHttpContext;
public class Jetty {
public static void main(String[] args) {
try {
Server server = new Server();
SocketListener listener = new SocketListener();
System.out.println("Max Thread :" + listener.getMaxThreads() + " Min Thread :" + listener.getMinThreads());
listener.setHost("localhost");
listener.setPort(8070);
listener.setMinThreads(5);
listener.setMaxThreads(250);
server.addListener(listener);
ServletHttpContext context = (ServletHttpContext) server.getContext("/");
context.addServlet("/MO", "jetty.HelloWorldServlet");
server.start();
server.join();
/*//We will create our server running at http://localhost:8070
Server server = new Server();
server.addListener(":8070");
//We will deploy our servlet to the server at the path '/'
//it will be available at http://localhost:8070
ServletHttpContext context = (ServletHttpContext) server.getContext("/");
context.addServlet("/MO", "jetty.HelloWorldServlet");
server.start();
*/
} catch (Exception ex) {
Logger.getLogger(Jetty.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
Servlet类:
package jetty;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class HelloWorldServlet extends HttpServlet
{
@Override
protected void doGet(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws ServletException, IOException
{
String appid = httpServletRequest.getParameter("appid");
String conta = httpServletRequest.getParameter("conta");
System.out.println("Appid : "+appid);
System.out.println("Conta : "+conta);
httpServletResponse.setContentType("text/plain");
PrintWriter out = httpServletResponse.getWriter();
out.println("Hello World!");
out.close();
}
}
从Java SE 6开始,在Sun Oracle JRE中有一个内置的HTTP服务器。Java 9模块名称为jdk.httpserver。httpserver包摘要概述了涉及的类并包含示例。
这里有一个从他们的文档复制粘贴的启动示例。你可以复制,粘贴,然后在Java 6+上运行。 (尽管如此,所有试图编辑它的人,因为它是一段丑陋的代码,请不要,这是一个复制粘贴,不是我的,此外,你不应该编辑引文,除非它们在原始来源中发生了变化)
package com.stackoverflow.q3732109; import java.io.IOException; import java.io.OutputStream; import java.net.InetSocketAddress; import com.sun.net.httpserver.HttpExchange; import com.sun.net.httpserver.HttpHandler; import com.sun.net.httpserver.HttpServer; public class Test { public static void main(String[] args) throws Exception { HttpServer server = HttpServer.create(new InetSocketAddress(8000), 0); server.createContext("/test", new MyHandler()); server.setExecutor(null); // creates a default executor server.start(); } static class MyHandler implements HttpHandler { @Override public void handle(HttpExchange t) throws IOException { String response = "This is the response"; t.sendResponseHeaders(200, response.length()); OutputStream os = t.getResponseBody(); os.write(response.getBytes()); os.close(); } } }
应该注意的是,他们示例中的response.length()部分是坏的,它应该是response.getBytes().length。即使这样,getBytes()方法也必须显式地指定在响应头中指定的字符集。唉,尽管对初学者有误导,但毕竟这只是一个基本的启动示例。
执行它并访问http://localhost:8000/test,你将看到以下响应:
这是反应
As to using com.sun.* classes, do note that this is, in contrary to what some developers think, absolutely not forbidden by the well known FAQ Why Developers Should Not Write Programs That Call 'sun' Packages. That FAQ concerns the sun.* package (such as sun.misc.BASE64Encoder) for internal usage by the Oracle JRE (which would thus kill your application when you run it on a different JRE), not the com.sun.* package. Sun/Oracle also just develop software on top of the Java SE API themselves like as every other company such as Apache and so on. Moreover, this specific HttpServer must be present in every JDK so there is absolutely no means of "portability" issue like as would happen with sun.* package. Using com.sun.* classes is only discouraged (but not forbidden) when it concerns an implementation of a certain Java API, such as GlassFish (Java EE impl), Mojarra (JSF impl), Jersey (JAX-RS impl), etc.
从Java 18开始,你可以用Java标准库创建简单的web服务器:
class Main {
public static void main(String[] args) {
var port = 8000;
var rootDirectory = Path.of("C:/Users/Mahozad/Desktop/");
var outputLevel = OutputLevel.VERBOSE;
var server = SimpleFileServer.createFileServer(
new InetSocketAddress(port),
rootDirectory,
outputLevel
);
server.start();
}
}
默认情况下,这将显示指定根目录的目录列表。您可以将index.html文件(以及CSS和JS文件等其他资产)放在该目录中来显示它们。
示例(我把这些放在桌面上,上面指定为我的根目录):
index . html:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Java 18 Simple Web Server</title>
<link rel="stylesheet" href="styles.css">
<style>h1 { color: blue; }</style>
<script src="scripts.js" defer>
let element = document.getElementsByTagName("h1")[0];
element.style.fontSize = "48px";
</script>
</head>
<body>
<h1>I'm <i>index.html</i> in the root directory.</h1>
</body>
</html>
旁注
对于Java标准库HTTP客户端,请参阅Java 11新HTTP客户端API。
这是我简单的web服务器,在JMeter中用于测试webhook(这就是为什么它会在收到请求后关闭并结束自己)。
import java.io.IOException;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
public class HttpServer {
private static int extractContentLength(StringBuilder sb) {
int length = 0;
String[] lines = sb.toString().split("\\n");
for (int i = 0; i < lines.length; i++) {
String s = lines[i];
if (s.toLowerCase().startsWith("Content-Length:".toLowerCase()) && i <= lines.length - 2) {
String slength = s.substring(s.indexOf(":") + 1, s.length()).trim();
length = Integer.parseInt(slength);
System.out.println("Length = " + length);
return length;
}
}
return 0;
}
public static void main(String[] args) throws IOException {
int port = Integer.parseInt(args[0]);
System.out.println("starting HTTP Server on port " + port);
StringBuilder outputString = new StringBuilder(1000);
ServerSocket serverSocket = new ServerSocket(port);
serverSocket.setSoTimeout(3 * 60 * 1000); // 3 minutes timeout
while (true) {
outputString.setLength(0); // reset buff
Socket clientSocket = serverSocket.accept(); // blocking
PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
try {
boolean isBodyRead = false;
int dataBuffer;
while ((dataBuffer = clientSocket.getInputStream().read()) != -1) {
if (dataBuffer == 13) { // CR
if (clientSocket.getInputStream().read() == 10) { // LF
outputString.append("\n");
}
} else {
outputString.append((char) dataBuffer);
}
// do we have Content length
int len = extractContentLength(outputString);
if (len > 0) {
int actualLength = len - 1; // we need to substract \r\n
for (int i = 0; i < actualLength; i++) {
int body = clientSocket.getInputStream().read();
outputString.append((char) body);
}
isBodyRead = true;
break;
}
} // end of reading while
if (isBodyRead) {
// response headers
out.println("HTTP/1.1 200 OK");
out.println("Connection: close");
out.println(); // must have empty line for HTTP
out.flush();
out.close(); // close clients connection
}
} catch (IOException ioEx) {
System.out.println(ioEx.getMessage());
}
System.out.println(outputString.toString());
break; // stop server - break while true
} // end of outer while true
serverSocket.close();
} // end of method
}
你可以这样测试:
curl -X POST -H "Content-Type: application/json" -H "Connection: close" -d '{"name": "gustinmi", "email": "gustinmi at google dot com "}' -v http://localhost:8081/
我玩得很开心,我玩转了一下,拼凑出了这个。我希望这对你有所帮助。 你需要安装Gradle或者使用Maven插件。
build.gradle
plugins {
id 'application'
}
group 'foo.bar'
version '1.0'
repositories {
mavenCentral()
}
application{
mainClass.set("foo.FooServer")
}
dependencies {}
FooServer 主入口点,你的主类。
package foo;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.ByteBuffer;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class FooServer {
public static void main(String[] args) throws IOException {
ServerSocket serverSocket = new ServerSocket(7654);
serverSocket.setPerformancePreferences(0, 1, 2);
/* the higher the numbers, the better the concurrent performance, ha!
we found that a 3:7 ratio to be optimal
3 partitioned executors to 7 network executors */
ExecutorService executors = Executors.newFixedThreadPool(3);
executors.execute(new PartitionedExecutor(serverSocket));
}
public static class PartitionedExecutor implements Runnable {
ServerSocket serverSocket;
public PartitionedExecutor(ServerSocket serverSocket) {
this.serverSocket = serverSocket;
}
@Override
public void run() {
ExecutorService executors = Executors.newFixedThreadPool(30);
executors.execute(new NetworkRequestExecutor(serverSocket, executors));
}
}
public static class NetworkRequestExecutor implements Runnable{
String IGNORE_CHROME = "/favicon.ico";
String BREAK = "\r\n";
String DOUBLEBREAK = "\r\n\r\n";
Integer REQUEST_METHOD = 0;
Integer REQUEST_PATH = 1;
Integer REQUEST_VERSION = 2;
String RENDERER;
Socket socketClient;
ExecutorService executors;
ServerSocket serverSocket;
public NetworkRequestExecutor(ServerSocket serverSocket, ExecutorService executors){
this.serverSocket = serverSocket;
this.executors = executors;
}
@Override
public void run() {
try {
socketClient = serverSocket.accept();
Thread.sleep(19);//do this for safari, its a hack but safari requires something like this.
InputStream requestInputStream = socketClient.getInputStream();
OutputStream clientOutput = socketClient.getOutputStream();
if (requestInputStream.available() == 0) {
requestInputStream.close();
clientOutput.flush();
clientOutput.close();
executors.execute(new NetworkRequestExecutor(serverSocket, executors));
return;
}
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
int bytesRead;
while ((bytesRead = requestInputStream.read(byteBuffer.array())) != -1) {
byteArrayOutputStream.write(byteBuffer.array(), 0, bytesRead);
if (requestInputStream.available() == 0) break;
}
String completeRequestContent = byteArrayOutputStream.toString();
String[] requestBlocks = completeRequestContent.split(DOUBLEBREAK, 2);
String headerComponent = requestBlocks[0];
String[] methodPathComponentsLookup = headerComponent.split(BREAK);
String methodPathComponent = methodPathComponentsLookup[0];
String[] methodPathVersionComponents = methodPathComponent.split("\\s");
String requestVerb = methodPathVersionComponents[REQUEST_METHOD];
String requestPath = methodPathVersionComponents[REQUEST_PATH];
String requestVersion = methodPathVersionComponents[REQUEST_VERSION];
if (requestPath.equals(IGNORE_CHROME)) {
requestInputStream.close();
clientOutput.flush();
clientOutput.close();
executors.execute(new NetworkRequestExecutor(serverSocket, executors));
return;
}
ConcurrentMap<String, String> headers = new ConcurrentHashMap<>();
String[] headerComponents = headerComponent.split(BREAK);
for (String headerLine : headerComponents) {
String[] headerLineComponents = headerLine.split(":");
if (headerLineComponents.length == 2) {
String fieldKey = headerLineComponents[0].trim();
String content = headerLineComponents[1].trim();
headers.put(fieldKey.toLowerCase(), content);
}
}
clientOutput.write("HTTP/1.1 200 OK".getBytes());
clientOutput.write(BREAK.getBytes());
Integer bytesLength = "hi".length();
String contentLengthBytes = "Content-Length:" + bytesLength;
clientOutput.write(contentLengthBytes.getBytes());
clientOutput.write(BREAK.getBytes());
clientOutput.write("Server: foo server".getBytes());
clientOutput.write(BREAK.getBytes());
clientOutput.write("Content-Type: text/html".getBytes());
clientOutput.write(DOUBLEBREAK.getBytes());
clientOutput.write("hi".getBytes());
clientOutput.close();
socketClient.close();
executors.execute(new NetworkRequestExecutor(serverSocket, executors));
} catch (IOException ex) {
ex.printStackTrace();
} catch (InterruptedException ioException) {
ioException.printStackTrace();
}
}
}
}
运行该程序:
gradle run
浏览:
http://localhost:7654/