Tomcat 手工编译及部署动态网站（Servlet & Spring Core）

[JasonWu73]

D:.
│   pom.xml
│
└───src
    ├───main
    │   ├───java
    │   │   └───net
    │   │       └───wuxianjie
    │   │           └───demo
    │   │                   MyFilter.java
    │   │                   MyListener.java
    │   │                   MyServlet.java
    │   │                   User.java
    │   │
    │   └───resources
    │           spring.xml
    │
    └───test
        └───java

添加 Maven 依赖

创建一个空的 Maven 项目，在 pom.xml 中添加类似如下的内容：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>net.wuxianjie</groupId>
  <artifactId>demo-java-web</artifactId>
  <version>1.0-SNAPSHOT</version>

  <properties>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <!-- 解决执行 `maven test` 时，控制台中文乱码的问题 -->
    <argLine>-Dfile.encoding=UTF-8</argLine>
  </properties>

  <dependencies>
    <!-- Java Servlet API -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
      <scope>provided</scope>
    </dependency>

    <!-- Spring Core -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.2.6.RELEASE</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <!-- 拷贝依赖文件 -->
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-dependency-plugin</artifactId>
        <version>3.1.1</version>
        <executions>
          <execution>
            <id>copy-dependencies</id>
            <phase>package</phase>
            <goals>
              <goal>copy-dependencies</goal>
            </goals>
            <configuration>
              <!-- 排除 JUnit 等运行时依赖 -->
              <includeScope>runtime</includeScope>
              <outputDirectory>${project.build.directory}/lib/</outputDirectory>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>

</project>

Spring Bean

package net.wuxianjie.demo;

public class User {

  private int userId;

  private String userName;

  public User(int userId, String userName) {
    this.userId = userId;
    this.userName = userName;
  }

  public int getUserId() {
    return userId;
  }

  public void setUserId(int userId) {
    this.userId = userId;
  }

  public String getUserName() {
    return userName;
  }

  public void setUserName(String userName) {
    this.userName = userName;
  }
}

src/main/resources/spring.xml：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

  <bean id="user" class="net.wuxianjie.demo.User">
    <constructor-arg index="0" value="101"/>
    <constructor-arg index="1" value="吴仙杰"/>
  </bean>

</beans>

Servlet

package net.wuxianjie.demo;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * 监听器
 *
 * <p>{@code ServletContext} 是一个全局的储存信息的空间。
 * 服务只要存在它就存在，服务关闭它就也没有了
 */
public class MyListener implements ServletContextListener {

  public void contextInitialized(ServletContextEvent sce) {

    ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");

    sce.getServletContext().setAttribute("spring", applicationContext);
  }

  public void contextDestroyed(ServletContextEvent sce) {

  }
}

package net.wuxianjie.demo;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

/**
 * 自定义过滤器（调用链）
 */
public class MyFilter implements Filter {

  /**
   * 初始化，在第一次 {@code doFilter()} 调用前调用
   *
   * <p>可获取 web.xml 文件中指定的参数
   */
  public void init(FilterConfig filterConfig) throws ServletException {

  }

  /**
   * 过滤行为，其中引入的 {@code FilterChain} 对象提供了后续过滤器信息
   *
   */
  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {

    // 需要设置两个编码，以防在某些条件下，其中一个未生效
    response.setCharacterEncoding("UTF-8");
    response.setContentType("text/html; charset=UTF-8");

    HttpServletRequest httpServletRequest = (HttpServletRequest) request;
    if (httpServletRequest.getHeader("User-Agent").toLowerCase().indexOf("chrome") > 0) {
      response.getWriter().write("不支持 Chrome 访问");
    } else {
      chain.doFilter(request, response);
    }
  }

  /**
   * {@code doFilter()} 中的所有活动都被该实例终止后，调用该方法
   */
  public void destroy() {

  }
}

package net.wuxianjie.demo;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.context.ApplicationContext;

public class MyServlet extends HttpServlet {

  @Override
  protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

    ApplicationContext applicationContext = (ApplicationContext) req.getServletContext().getAttribute("spring");

    User user = applicationContext.getBean("user", User.class);

    String userName = req.getParameter("user_name");

    String resultUserName = userName == null || userName.trim().length() <= 0 ? user.getUserName() : userName;

    resp.getWriter().write("你好，" + resultUserName);
  }
}

手工编译及部署

1、编译项目：

$ mvn package

2、在 $CATALINA_HOME/webapps 目录创建一个空的 myweb 文件夹

3、在 myweb 文件夹中再创建一个空的 WEB-INF 文件夹

WEB-INF 是 Tomcat 的安全目录。该目录中的文件不能被浏览器直接访问，如 web.xml、classes 和 lib 等都是放在该目录中的。

4、将项目编译生成的 classes、lib 文件夹拷贝到 $CATALINA_HOME/webapps/myweb/WEB-INF 中

5、在 $CATALINA_HOME/webapps/myweb/WEB-INF 中创建 web.xml 文件，内容如下：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
                      http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
  version="3.1">

  <!-- My Filter -->
  <filter>
    <filter-name>myFilter</filter-name>
    <filter-class>net.wuxianjie.demo.MyFilter</filter-class>
  </filter>

  <filter-mapping>
    <filter-name>myFilter</filter-name>
    <url-pattern>*.do</url-pattern>
  </filter-mapping>
  <!-- ./My Filter -->

  <!-- My Servlet -->
  <servlet>
    <servlet-name>myServlet</servlet-name>
    <servlet-class>net.wuxianjie.demo.MyServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>myServlet</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping>
  <!-- ./My Servlet -->

  <!-- My Listener -->
  <listener>
    <listener-class>net.wuxianjie.demo.MyListener</listener-class>
  </listener>
  <!-- ./My Listener -->

</web-app>

6、启动 Tomcat，然后通过浏览器等 HTTP 工具访问我们的服务，例如：GET http://localhost:8080/myweb/abc.do?user_name=张三