嵌入式 tomcat的使用

tomcat

@WebServlet

• @WebServlet 是servlet 3.0的写法
• 新建maven项目，结构如下

• pom文件

  4.0.0
  com.adagio
  tomcat-demo
  0.0.1-SNAPSHOT
  war
  
  
    UTF-8
  
  
  
      
         Javax.servlet
         javax.servlet-api
         3.1.0
         provided
     

     
         org.apache.tomcat.maven
         tomcat7-maven-plugin
         2.1
     
  
  
  
      
          
               org.apache.maven.plugins
              maven-compiler-plugin
              2.3.2
              
                  1.8
                  1.8
              
          
      
          
              org.apache.maven.plugins
             maven-war-plugin
             3.2.0
             
                 false
             
          
      
  

• Java Code

package com.adagio;

import java.io.IOException;

import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(urlPatterns = "/demo")
public class DemoServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
        request.setCharacterEncoding("UTF-8");
        response.setCharacterEncoding("UTF-8");
        response.setContentType("text/html;charset=UTF-8");
        
        String message = request.getParameter("message");
        
        response.getWriter().print(message);
        response.getWriter().println("
");
        
    }
    
}

• 打包：mvn -Dmaven.test.skip -U clean package
• 启动：war包放到tomcat/webapps目录下，启动tomcat
• 访问：http://localhost:8080/tomcat-demo-0.0.1-SNAPSHOT/demo?message=hello

使用maven插件，构建嵌入式容器

• POM文件中添加

                org.apache.tomcat.maven
                tomcat7-maven-plugin
                2.1
                
                    
                        tomcat-run
                        
                            exec-war-only
                        
                        package
                        
                            
                            /
                        
                    
                
            

• 打包：mvn -Dmaven.test.skip -U clean package
• 启动：java -jar targettomcat-demo-0.0.1-SNAPSHOT-war-exec.jar
• 访问：http://localhost:8080/demo?message=hello
• 解压jar包，找到 META-INF/MANIFEST.MF

Manifest-Version: 1.0
Main-Class: org.apache.tomcat.maven.runner.Tomcat7RunnerCli

• 可以得出jar 的启动类：org.apache.tomcat.maven.runner.Tomcat7RunnerCli

模拟server.xml，构建嵌入式容器

源码

import java.io.File;

import org.apache.catalina.Context;
import org.apache.catalina.Host;
import org.apache.catalina.Service;
import org.apache.catalina.Wrapper;
import org.apache.catalina.connector.Connector;
import org.apache.catalina.core.StandardContext;
import org.apache.catalina.startup.Tomcat;

/**
 * 访问 ： http://localhost:9527/index.jsp
 * http://localhost:9527/demo?message=hello
 *
 */
public class EmbeddedTomcatServer {

    public static void main(String[] args) throws Exception {
        
        //确定classes 目录绝对路径
        String calssesPath = System.getProperty("user.dir") + 
                File.separator + "target" + File.separator + "classes";
        System.out.println(calssesPath);
        
        //创建Tomcat实例
        Tomcat tomcat = new Tomcat();
        tomcat.setPort(9527);
        
        //设置Host
        Host host = tomcat.getHost();
        host.setName("localhost");
        host.setAppBase("webapps");
        
        //设置 Context
        //server.xml - 
        String webapp = System.getProperty("user.dir") + File.separator
                + "src" + File.separator + "main" + File.separator + "webapp";
        String contextPath = "/";
        //设置 webapp 绝对路径到 Context，作为它的docBase
        Context context = tomcat.addWebapp(contextPath, webapp);
        if(context instanceof StandardContext) {
            StandardContext standardContext = new StandardContext();
            // 设置默认的web.xml文件到Context
            standardContext.setDefaultContextXml(calssesPath + File.separator + "conf/web.xml");
            
            //设置 Classpath 到Context
            // 添加DemoServlet到tomcat 容器
            Wrapper wrapper = tomcat.addServlet(contextPath, "DemoServlet", new DemoServlet());
            wrapper.addMapping("/demo");
        }
        
        
        //http://localhost:9526/demo?message=%E5%B0%8F%E9%A9%AC
        
        //设置Service
        Service service = tomcat.getService();
        Connector connector = new Connector();
        //这里设置了一个port，等于两个端口都可以使用，但是上面那个端口访问中文乱码
        connector.setPort(9526);
        connector.setURIEncoding("UTF-8");
        connector.setProtocol("HTTP/1.1");
        service.addConnector(connector);
        
        
        
        //启动 tomcat 服务器
        tomcat.start();        
        // 强制 Tomcat Server 等待，避免main线程执行结束关闭
        tomcat.getServer().await();
    }
}

文件

• 直接从tomcat/conf copy web.xml到项目中
• 在resources下建 conf目录，把copy的web.xml放进去
• 在webapp下新建 index.jsp
• 具体如图

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