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JAVA学习笔记（中）——未完待续

发布于2021-05-29 21:57 阅读(1049) 评论(0) 点赞(21) 收藏(1)

Maven

https://maven.apache.org/download.cgi
下载apache-maven-3.8.1-bin.zip
命令行mvn -version

Servlet

1、热身

打开idea，create new project，Maven，maven-archetype-webapp

在这里插入图片描述

导入Tomcat：Add Configuration， Tomcat Server， local
运行Tomcat就会打开浏览器看到首页（第一个项目教程到此结束）
补充说明：右边maven方法

在这里插入图片描述

补充说明：颜色标记意义

2、HelloServlet

创建空maven项目servlet01，再创建HelloServlet与HiServlet两个带首页模板的新module

在这里插入图片描述

设置各模块的Artifacts

在这里插入图片描述

配置Tomcat服务器

在这里插入图片描述

成功访问http://localhost:8080/HelloServlet_war/
成功访问http://localhost:8080/HiServlet_war/
可选项：修改web.xml中web-app字段为最新

3、HiServlet

在main加添加java与resources文件夹并分别标记，在 java文件夹中创建新包，包中创建新类，建立映射
下面我把整个项目当前所有文件的代码放上来

package com.cj.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 ErrorTest extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html");
        resp.setCharacterEncoding("utf-8");
        PrintWriter writer=resp.getWriter();
        writer.print("<h1>对不起404</h1>");
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doGet(req, resp);
    }
}

package com.cj.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 HelloTest extends HttpServlet {
    //ctrl+o可以选择要重写的方法
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        PrintWriter writer=resp.getWriter();
        writer.print("Hello,Servlet");
        //在web.xml文件中绑定com.cj.servlet.servlet_test_01类映射到/hello路径中
        //浏览器访问localhost:8080/hello即可看到"Hello,Servlet"字样
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doGet(req, resp);
    }
}

<!DOCTYPE web-app PUBLIC
        "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
        "http://java.sun.com/dtd/web-app_2_3.dtd" >
<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"
         metadata-complete="true">
  <servlet>
    <servlet-name>hello</servlet-name>
    <servlet-class>com.cj.servlet.HelloTest</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>hello</servlet-name>
    <url-pattern>/hello</url-pattern>
  </servlet-mapping>
  <servlet>
    <servlet-name>error</servlet-name>
    <servlet-class>com.cj.servlet.ErrorTest</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>error</servlet-name>
    <url-pattern>/error</url-pattern>
  </servlet-mapping>
</web-app>

<html>
<body>
<h2>Hello World!1</h2>
</body>
</html>

<?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">
    <parent>
        <artifactId>servlet01</artifactId>
        <groupId>com.cj</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>HelloServlet</artifactId>
    <packaging>war</packaging>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

</project>

<!DOCTYPE web-app PUBLIC
        "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
        "http://java.sun.com/dtd/web-app_2_3.dtd" >
<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"
         metadata-complete="true">
</web-app>

<html>
<body>
<h2>Hello World!2</h2>
</body>
</html>

<?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">
    <parent>
        <artifactId>servlet01</artifactId>
        <groupId>com.cj</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>HiServlet</artifactId>
    <packaging>war</packaging>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

</project>

<?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.cj</groupId>
    <artifactId>servlet01</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>HiServlet</module>
        <module>HelloServlet</module>
    </modules>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>4.0.1</version>
            <scope>provided</scope>
        </dependency>
        <!-- https://mvnrepository.com/artifact/javax.servlet.jsp/javax.servlet.jsp-api -->
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>javax.servlet.jsp-api</artifactId>
            <version>2.3.3</version>
            <scope>provided</scope>
        </dependency>

    </dependencies>

</project>