JavaWeb

Tomcat

目录结构

根目录

conf目录

server.xml

配置端口号：

配置地址：

webapps目录

网页页面文件存放目录，可以通过server.xml更改目录名称。

每个目录对应一个app，访问localhost:8080默认进入ROOT下的index.jsp文件

目录结构：

--webapps : tomcat服务器的web目录
    -ROOT
    -someApp : 网站app的目录名
        - WEB-INF
        	-classes : java程序
            -lib : web应用依赖的jar包
            -web.xml : 网站配置文件
        - index.html : 默认的首页
        - static
            -css
            	-style.css
            -js
            -img
        - ...

MAVEN

配置

环境变量配置

MAVEN_HOME：D:\Code\Env\Java\apache-maven-3.6.3

M2_HOME：D:\Code\Env\Java\apache-maven-3.6.3\bin

PATH：%MAVEN_HOME%\bin

镜像配置

作用：加速国内下载

在maven目录下/conf/setting.xml中配置

 <mirrors>
   <!-- mirror
    | Specifies a repository mirror site to use instead of a given repository. The repository that
    | this mirror serves has an ID that matches the mirrorOf element of this mirror. IDs are used
    | for inheritance and direct lookup purposes, and must be unique across the set of mirrors.
    |
   <mirror>
     <id>mirrorId</id>
     <mirrorOf>repositoryId</mirrorOf>
     <name>Human Readable Name for this Mirror.</name>
     <url>http://my.repository.com/repo/path</url>
   </mirror>
    -->
    <mirror>
    <id>alimaven</id>
    <name>aliyun maven</name>
    <url>http://maven.aliyun.com/nexus/content/groups/public/</url>
    <mirrorOf>central</mirrorOf>
</mirror>
 </mirrors>

本地仓库配置

<localRepository>D:/Code/Env/Java/apache-maven-3.6.3/maven-repo</localRepository>

IDEA中配置

新建MAVEN项目/模块，选择相关路径

模块的maven配置文件：pom.xml

<!--项目依赖文件，需要其他模块手动添加到新节点中-->
<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.11</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>4.0.1</version>
    </dependency>

    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>jsp-api</artifactId>
        <version>2.1</version>
    </dependency>
</dependencies>

Servlet

1. 编写servlet

package com.i.hello;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

// 继承自HttpServlet
public class hello extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setCharacterEncoding("utf-8");  // 设置编码
        // 网页打印<h1>hello servlet!</h1>
        PrintWriter writer = resp.getWriter(); 
        writer.println("<h1>hello servlet!</h1>");
        System.out.println("do Get！");
    }

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

2. 配置路由映射

配置web.xml文件

<web-app>
  <display-name>Archetype Created Web Application</display-name>

  <!--    定义一个servlet路由-->
  <servlet>
<!--    servlet名称-->
    <servlet-name>hello</servlet-name>
<!--    对应的类-->
    <servlet-class>com.i.hello.hello</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>hello</servlet-name>
<!--    url映射,访问host:port/hello可以返回页面-->
    <url-pattern>/hello</url-pattern>
  </servlet-mapping>
</web-app>

Mapping

映射路径配置在对应app下web.xml下配置

需要配置servlet对应的类和对应的URL

1. 一个Servlet指定一个映射路径

<!--    定义一个servlet路由-->
<servlet>
  <servlet-name>hello</servlet-name>
  <servlet-class>com.i.hello.hello</servlet-class>
</servlet>

<servlet-mapping>
  <servlet-name>hello</servlet-name>
  <url-pattern>/hello</url-pattern>
</servlet-mapping>

2. 一个Servlet指定多个映射路径

 <servlet>
   <servlet-name>hello</servlet-name>
   <servlet-class>com.i.hello.hello</servlet-class>
 </servlet>

 <servlet-mapping>
   <servlet-name>hello</servlet-name>
   <url-pattern>/hello</url-pattern>
 </servlet-mapping>

<servlet-mapping>
   <servlet-name>hello</servlet-name>
   <url-pattern>/hello1</url-pattern>
 </servlet-mapping>      

<servlet-mapping>
     <servlet-name>hello</servlet-name>
   <url-pattern>/hello2</url-pattern>
 </servlet-mapping>

3. 一个Servlet指定通用映射路径

   访问所有未显式指定的域名时都会访问/*URL映射的Servlet

   但访问/hello时会正常跳转至hello指向的内容

<servlet>
  <servlet-name>idnex</servlet-name>
  <servlet-class>com.i.hello.Index</servlet-class>
</servlet>

<servlet-mapping>
  <servlet-name>index</servlet-name>
  <url-pattern>/*</url-pattern>
</servlet-mapping>

<servlet>
  <servlet-name>hello</servlet-name>
  <servlet-class>com.i.hello.hello</servlet-class>
</servlet>

<servlet>
  <servlet-name>error</servlet-name>
  <servlet-class>com.i.hello.ErrorServlet</servlet-class>
</servlet>

<servlet-mapping>
  <servlet-name>hello</servlet-name>
  <url-pattern>/hello</url-pattern>
</servlet-mapping>

<servlet-mapping>
  <servlet-name>error</servlet-name>
  <url-pattern>/error/*</url-pattern>
</servlet-mapping>

4. 指定url的一些后缀或前缀

<servlet-mapping>
  <servlet-name>hello</servlet-name>
  <url-pattern>*.hello</url-pattern>
</servlet-mapping>

• 注意：*前面不能加/否则会报错。另外，但存在通配符/*时，好像会优先走通配符(未深度测试).

ServletContext

是Tomcat中的一个全局对象，是唯一的，即是个单例，所有应用共享。可以用于网页间传值。

共享数据

// 设置
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    resp.setCharacterEncoding("utf-8");
    resp.setHeader("content-type","text/html;charset=UTF-8");
	// 获取ServletContext全局对象
    ServletContext context = this.getServletContext();
    // 设置属性值
    context.setAttribute("name","Xiaoi");

    PrintWriter writer = resp.getWriter();
    writer.println("<h1>用户名已设置</h1>");
    System.out.println("do Get！");
}

// 获取
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    resp.setCharacterEncoding("utf-8");
    resp.setHeader("content-type","text/html;charset=UTF-8");
    
	// 获取ServletContext全局对象
    ServletContext context = this.getServletContext();
    // 获取属性值
    String contextAttribute = (String) context.getAttribute("name");

    PrintWriter writer = resp.getWriter();
    writer.println("<h1>用户名</h1>");
    writer.println(contextAttribute);
    System.out.println("do Get！");
}