【脱Eclipse】Visual Studio CodeによるJavaのホットデプロイ環境構築

java_product
├── .devcontainer
│   └── devcontainer.json
├── development
│   └── Dockerfile
├── docker-compose.yml
└── java

# openjdk11のイメージを利用。
FROM openjdk:11
 
# ローカルのソースコードをマウントするためのディレクトリを作成。
RUN mkdir /opt/project
 
# tomcatをダウンロードして/usr/localに配置、mavenもインストールしておく。
RUN apt-get update && \
    apt-get -y install maven && \
    curl -sL https://dlcdn.apache.org/tomcat/tomcat-9/v9.0.58/bin/apache-tomcat-9.0.58.tar.gz \
    | tar zx -C /usr/local

{
  // 任意の名前でOK。
  "name": "java_project",
 
  // コンテナを作成するためのdocker-compose.ymlを指定。
  "dockerComposeFile": [
		"../docker-compose.yml"
  ],
 
  // port転送設定。
  "forwardPorts": [8080],
  //docker-compose.ymlのservicesと合わせる
  "service": "tomcat", 
  // コンテナログインした際のカレントディレクトリ指定。
  "workspaceFolder": "/opt/project",
 
  // コンテナが生成されたときに、コンテナ側にインストールするVSCodeの拡張機能。
  // 今回はJava Extension PackとTomcat for Javaをインストール。
  "extensions": [
    "adashen.vscode-tomcat",
    "vscjava.vscode-java-pack"
  ],
  "settings": {
	 "java.debug.settings.hotCodeReplace": "auto" 
  }
}

version: '3.5'
services:
  tomcat:
    container_name: tomcat
    build: ./development
    volumes:
      - "data:/opt/project"
    environment:
      - TZ=Asia/Tokyo
    network_mode: host
    tty: true
volumes:
  data:
    driver: local
    driver_opts:
      type: none
      device: ${PWD}/java
      o: bind

demo
├── src
│   └── main
│         ├── java ★
│         │     ├── com ★
│         │     │       └── example ★
│         │     │              └── servlet ★
│         │     │                     └── MyServlet.java ★
│         │     └──logback.xml ★
│         └── webapp
│                ├── WEB-INF
│                │      └── web.xml
│                └── index.jsp
├── target
│     └── ・・・
└── pom.xml

package com.example.servlet;

import java.io.IOException;
import javax.servlet.*;
import javax.servlet.http.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


public class MyServlet extends HttpServlet {

  private static final long serialVersionUID = 1L;
  //private static final Logger logger = LoggerFactory.getLogger(MyServlet.class);

  /**
   * @see HttpServlet#HttpServlet()
   */
  public MyServlet() {
      super();
  }

  /**
   * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
   *      response)
   */
  protected void doGet(HttpServletRequest request, HttpServletResponse response)
          throws ServletException, IOException {
      //logger.info("Debug OK");
      response.getWriter().append("Hello Java!");
  }

  /**
   * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
   *      response)
   */
  protected void doPost(HttpServletRequest request, HttpServletResponse response)
          throws ServletException, IOException {
      doGet(request, response);
  }

}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE logback>
<configuration>
    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <pattern>%d{yyyy/MM/dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
        </encoder>
    </appender>

    <root level="info">
        <appender-ref ref="STDOUT" />
    </root>
</configuration>

・・・・・ 
 <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <java.version>11</java.version>
		<maven.compiler.target>${java.version}</maven.compiler.target>
		<maven.compiler.source>${java.version}</maven.compiler.source>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
    <dependency>
			<groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>4.0.1</version>
      <scope>provided</scope>
		</dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
      <version>1.7.25</version>
    </dependency>
    <dependency>
      <groupId>ch.qos.logback</groupId>
      <artifactId>logback-classic</artifactId>
      <version>1.2.10</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>ch.qos.logback</groupId>
      <artifactId>logback-core</artifactId>
      <version>1.2.10</version>
    </dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-simple</artifactId>
      <version>1.6.1</version>
    </dependency>
  </dependencies>
・・・・・

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>My Servlet Web Application</display-name>

  <servlet>
    <servlet-name>MyServlet</servlet-name>
    <servlet-class>com.example.servlet.MyServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>MyServlet</servlet-name>
    <url-pattern>/my-servlet/*</url-pattern>
  </servlet-mapping>
</web-app>

package com.example.servlet;

import java.io.IOException;
import javax.servlet.*;
import javax.servlet.http.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


public class MyServlet extends HttpServlet {

  private static final long serialVersionUID = 1L;
  private static final Logger logger = LoggerFactory.getLogger(MyServlet.class);　//★

  /**
   * @see HttpServlet#HttpServlet()
   */
  public MyServlet() {
      super();
  }

  /**
   * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
   *      response)
   */
  protected void doGet(HttpServletRequest request, HttpServletResponse response)
          throws ServletException, IOException {
      logger.info("Debug OK");　//★
      response.getWriter().append("Hello Java!");
  }

  /**
   * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
   *      response)
   */
  protected void doPost(HttpServletRequest request, HttpServletResponse response)
          throws ServletException, IOException {
      doGet(request, response);
  }

}