javaweb——嵌入tomcat(spring-boot)

待我称王封你为后i 2022-07-12 06:25 134阅读 0赞

原创文章，转载请注明出处

关于嵌入tomcat的文章，还可以参考之前写的[《javaweb——嵌入tomcat 》][javaweb_tomcat]  
        这里使用spring-boot，实际上spring-boot已经嵌入了常用的servlet容器，tomcat和jetty。默认是tomcat。

看下效果吧

![Center][]

我们看一下怎么搭建吧

使用maven，清单如下：

<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>spring-boot-demo</groupId>
      <artifactId>spring-boot-demo</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      <packaging>war</packaging>
      <name/>
      <description/>
      <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
      </properties>
      <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>1.3.0.RELEASE</version>
      </parent>
      <dependencies>
     
        <dependency>
          <groupId>javax.servlet</groupId>
          <artifactId>jstl</artifactId>
          <version>1.2</version>
          <scope>provided</scope>
        </dependency>
        <dependency>
          <groupId>javax.servlet.jsp</groupId>
          <artifactId>jsp-api</artifactId>
          <version>2.1</version>
          <scope>provided</scope>
        </dependency>
        
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        
        
         
         
        
      </dependencies>
      <build>
        <plugins>
          <plugin>
            <artifactId>maven-war-plugin</artifactId>
          </plugin>
          <plugin>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
              <source>1.6</source>
              <target>1.6</target>
            </configuration>
          </plugin>
        </plugins>
        
        <finalName>spring-boot-demo</finalName>
        
      </build>
    </project>

实现入口类

@SpringBootApplication
    public class Application {
    
    	public static void main(String[] args){
    		SpringApplication.run(Application.class, args);
    	}
    	
    }

最后是tomcat的配置，如果不进行配置将使用默认配置。还可以用配置文件进行，但是没有代码灵活，这里使用代码进行配置

@Configuration
    public class TomcatConfig {
    
    	@Bean
        public EmbeddedServletContainerFactory servletContainer() {
            TomcatEmbeddedServletContainerFactory tomcat = new TomcatEmbeddedServletContainerFactory();
            tomcat.setUriEncoding(Charset.forName("UTF-8"));
            tomcat.setAddress((java.net.InetAddress) null);
            tomcat.setContextPath("/springBootDemo");
            tomcat.setPort(8888);
            return tomcat;
        }
    	
    }

看着是不是很熟悉，和tomcat7的api很像。顺便来看一下源码吧

TomcatEmbeddedServletContainerFactory的getEmbeddedServletContainer方法

@Override
    	public EmbeddedServletContainer getEmbeddedServletContainer(
    			ServletContextInitializer... initializers) {
    		Tomcat tomcat = new Tomcat();
    		File baseDir = (this.baseDirectory != null ? this.baseDirectory
    				: createTempDir("tomcat"));
    		tomcat.setBaseDir(baseDir.getAbsolutePath());
    		Connector connector = new Connector(this.protocol);
    		tomcat.getService().addConnector(connector);
    		customizeConnector(connector);
    		tomcat.setConnector(connector);
    		tomcat.getHost().setAutoDeploy(false);
    		tomcat.getEngine().setBackgroundProcessorDelay(-1);
    		for (Connector additionalConnector : this.additionalTomcatConnectors) {
    			tomcat.getService().addConnector(additionalConnector);
    		}
    		prepareContext(tomcat.getHost(), initializers);
    		return getTomcatEmbeddedServletContainer(tomcat);
    	}

看到没有，Tomcat tomcat=new Tomcat();在这里调用了tomcat api的东西，接下来的配置应该很熟悉把，可以看一下 [《javaweb——嵌入tomcat 》][javaweb_tomcat]这篇文章

然后我们看看getTomcatEmbeddedServletContainer这个方法

protected TomcatEmbeddedServletContainer getTomcatEmbeddedServletContainer(
    			Tomcat tomcat) {
    		return new TomcatEmbeddedServletContainer(tomcat, getPort() >= 0);
    	}

这个工厂最后获得的是一个TomcatEmbeddedServletContainer的对象，该对象封装了原生的tomcat

看看TomcatEmbeddedServletContainer的构造器

public TomcatEmbeddedServletContainer(Tomcat tomcat, boolean autoStart) {
    		Assert.notNull(tomcat, "Tomcat Server must not be null");
    		this.tomcat = tomcat;
    		this.autoStart = autoStart;
    		initialize();
    	}

至此我们已经知道了spring-boot内嵌tomcat的原理了。这样也就清楚为什么spring-boot需要tomcat的版本至少是tomcat7

[javaweb_tomcat]: http://blog.csdn.net/guduyishuai/article/details/55094671
[Center]: /images/20220711/58853b6eeacf46928bd5b120c46ed8c5.png