idea 如何新建一个Maven项目并且写第一个servlet

素颜马尾好姑娘i 2022-04-04 09:08 357阅读 0赞

使用idea已经有段时间了，但是一直没有自己亲自新建一个项目，从头开始写一个Servlet，今天就来学习一下，并且记一个笔记。

一。

1.首先，打开idea new-->Project

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXlpbmcxODAyMDI4OTE1_size_16_color_FFFFFF_t_70][]

2.选择Maven 项目 点击下一步

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXlpbmcxODAyMDI4OTE1_size_16_color_FFFFFF_t_70 1][]

3.填写groupid 和 Artifactid  如下：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXlpbmcxODAyMDI4OTE1_size_16_color_FFFFFF_t_70 2][]

4.点击下一步 选择一个路径，这个路径是存放你项目的路径

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXlpbmcxODAyMDI4OTE1_size_16_color_FFFFFF_t_70 3][]

5.完了之后，用一个新窗口打开：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXlpbmcxODAyMDI4OTE1_size_16_color_FFFFFF_t_70 4][]

目录结构如下：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXlpbmcxODAyMDI4OTE1_size_16_color_FFFFFF_t_70 5][]

6.然后将mav项目，转成web项目

右键项目Add Framework Support

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXlpbmcxODAyMDI4OTE1_size_16_color_FFFFFF_t_70 6][]

7.添加Web Application 支持

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXlpbmcxODAyMDI4OTE1_size_16_color_FFFFFF_t_70 7][]

8.点击ok 后，项目就变为了web项目，看如下目录：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXlpbmcxODAyMDI4OTE1_size_16_color_FFFFFF_t_70 8][]

9.然后基本的项目已经起来了，然后就是写代码了，

二。

1.在src-->main-->java 下新建一个包 com.demo.servlet  然后在此包下新建一个 HttpServlet 类

2.然后在此类下书写代码，首先HttpServlet 类要继承HttpServlet ,但是我在写这个继承的时候没有给我提示，如下所示：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXlpbmcxODAyMDI4OTE1_size_16_color_FFFFFF_t_70 9][]

只要是因为这个工程还没有添加 对servlet的支持，下面在pom文件中添加对 servlet的支持

<dependencies>
            
            <dependency>
                <groupId>Javax.servlet</groupId>
                <artifactId>servlet-api</artifactId>
                <version>3.0-alpha-1</version>
            </dependency>
        </dependencies>

pom文件如下：

<?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>com.demo</groupId>
        <artifactId>hellodemo02</artifactId>
        <version>1.0-SNAPSHOT</version>
    
        <dependencies>
            
            <dependency>
                <groupId>Javax.servlet</groupId>
                <artifactId>servlet-api</artifactId>
                <version>3.0-alpha-1</version>
            </dependency>
        </dependencies>
    
    </project>

3.此时再继承HttpServlet 就有这个提示了：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXlpbmcxODAyMDI4OTE1_size_16_color_FFFFFF_t_70 10][]

4.继承HttpServlet之后，需要重写doGet方法，在idea中 使用快捷键 Ctrl+O 选择重写的方法

写完之后下面是HelloServlet的代码

package com.demo.servlet;
    
    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;
    
    public class HelloServlet extends HttpServlet {
        @Override
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            PrintWriter out = response.getWriter();
            try {
                request.setCharacterEncoding("UTF-8");
    
                response.setContentType("text/html; charset=utf-8");
                response.setCharacterEncoding("UTF-8");
                String userId = request.getParameter("userId");
                String pwd = request.getParameter("pwd");
                if("admin".equals(userId) && "password".equals(pwd)){
                    out.println("success");
                }else{
                    out.println("fail");
                }
                out.println("<br/>");
                String servletPath = this.getServletContext().getRealPath("/");
                out.println(servletPath);
                out.close();
    
            } catch (Exception e) {
                // TODO: handle exception
            }
        }
    }

5.写完HelloServlet之后还不行，我们还没有在web.xml中进行配置

下面是web.xml中的内容

<?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_4_0.xsd"
             version="4.0">
    
        <display-name>hellodemo</display-name>
        <servlet>
            <servlet-name>HelloServlet</servlet-name>
            <servlet-class>com.demo.servlet.HelloServlet</servlet-class>
        </servlet>
        <servlet-mapping>
            <servlet-name>HelloServlet</servlet-name>
            <url-pattern>/hello</url-pattern>
        </servlet-mapping>
    </web-app>

6.再然后就是在idea中配置tomcat了 如何配置我这里就不写了 我也会大家都会，我就把截图放一下吧：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXlpbmcxODAyMDI4OTE1_size_16_color_FFFFFF_t_70 11][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXlpbmcxODAyMDI4OTE1_size_16_color_FFFFFF_t_70 12][]

之后启动timcat 访问：

[http://localhost:8080/demo02/hello][http_localhost_8080_demo02_hello]  
页面如下：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXlpbmcxODAyMDI4OTE1_size_16_color_FFFFFF_t_70 13][]  
砍我HelloServlet 中 的写法 我这么访问：

[http://localhost:8080/demo02/hello?userId=admin&pwd=password][http_localhost_8080_demo02_hello_userId_admin_pwd_password]

返回的页面就是success

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpdXlpbmcxODAyMDI4OTE1_size_16_color_FFFFFF_t_70 14][]

至此，使用idea 新建一个Maven项目，并且书写第一个Servlet 完成，接下来，研究一下HttpServlet

不积跬步，无以至千里

不积小流，无以成江海

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[http_localhost_8080_demo02_hello]: http://localhost:8080/demo02/hello
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[http_localhost_8080_demo02_hello_userId_admin_pwd_password]: http://localhost:8080/demo02/hello?userId=admin&pwd=password
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