嵌入式 Tomcat (Embedded Tomcat)

嵌入式 Tomcat 作为嵌入 Java 应用程序的库, 你可以在 mvnrepository 下载 发行版Jar 以及源码

https://mvnrepository.com/search?q=embed+tomcat

作为最基本的依赖, 你需要以下几个库

• Tomcat Embed Core
• Tomcat Embed Logging JULI
• Tomcat Annotations API

现在, 让我们把 tomcat 跑起来

package develon.test;

import java.io.File;
import java.io.IOException;
import java.io.Writer;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.catalina.Context;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.connector.Connector;
import org.apache.catalina.startup.Tomcat;

public final class Main {
    File tmpDir = new File("F:\\Game\\tomcat");
    Tomcat tomcat = new Tomcat();
    
    public static void main(String[] args) throws Throwable {
        new Main().init();
    }
    
    private void init() throws Throwable {
        Runtime.getRuntime().addShutdownHook(new Thread(() -> {
                try {
                    tomcat.destroy();
                } catch (LifecycleException e) {
                    e.printStackTrace();
                }
            })
        );
        test();
    }

    private void test() throws Throwable {
        tomcat.setBaseDir(tmpDir.getAbsolutePath()); // 设置工作目录
        tomcat.setHostname("localhost"); // 主机名, 将生成目录: {工作目录}/work/Tomcat/{主机名}/ROOT
        System.out.println("工作目录: " + tomcat.getServer().getCatalinaBase().getAbsolutePath());

        tomcat.setPort(80);
        Connector conn = tomcat.getConnector(); // Tomcat 9.0 必须调用 Tomcat#getConnector() 方法之后才会监听端口
        System.out.println("连接器设置完成: " + conn);
        
        // contextPath要使用的上下文映射，""表示根上下文
        // docBase上下文的基础目录，用于静态文件。相对于服务器主目录必须存在 ({主目录}/webapps/{docBase})
        Context ctx = tomcat.addContext("", /*{webapps}/~*/ "/ROOT");

        Tomcat.addServlet(ctx, "globalServlet", new HttpServlet() {
            private static final long serialVersionUID = 1L;

            @Override
            protected void service(HttpServletRequest request, HttpServletResponse response)
                    throws ServletException, IOException {
                response.setCharacterEncoding("UTF-8");
                response.setContentType("text/plain");
                response.setHeader("Server", "Embedded Tomcat");
                try (Writer writer = response.getWriter()) {
                    writer.write("Hello, Embedded Tomcat!");
                    writer.flush();
                }
            }
        });
        ctx.addServletMappingDecoded("/", "globalServlet");

        tomcat.start();
        System.out.println("tomcat 已启动");
        tomcat.getServer().await();
    }

}