Maven配置xml文件

<?xml version="1.0" encoding="UTF-8"?>
<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 http://maven.apache.org/xsd/settings-1.0.0.xsd">

    <mirrors>
        <mirror>
            <id>alimaven</id>
            <mirrorOf>central</mirrorOf>
            <name>aliyun maven</name>
            <url>http://maven.aliyun.com/nexus/content/repositories/central/</url>
        </mirror>
        <mirror>
            <id>alimaven</id>
            <name>aliyun maven</name>
            <url>http://maven.aliyun.com/nexus/content/groups/public/</url>
            <mirrorOf>central</mirrorOf>
        </mirror>
        <mirror>
            <id>central</id>
            <name>Maven Repository Switchboard</name>
            <url>http://repo1.maven.org/maven2/</url>
            <mirrorOf>central</mirrorOf>
        </mirror>
        <mirror>
            <id>repo2</id>
            <mirrorOf>central</mirrorOf>
            <name>Human Readable Name for this Mirror.</name>
            <url>http://repo2.maven.org/maven2/</url>
        </mirror>
        <mirror>
            <id>ibiblio</id>
            <mirrorOf>central</mirrorOf>
            <name>Human Readable Name for this Mirror.</name>
            <url>http://mirrors.ibiblio.org/pub/mirrors/maven2/</url>
        </mirror>
        <mirror>
            <id>jboss-public-repository-group</id>
            <mirrorOf>central</mirrorOf>
            <name>JBoss Public Repository Group</name>
            <url>http://repository.jboss.org/nexus/content/groups/public</url>
        </mirror>
        <mirror>
            <id>google-maven-central</id>
            <name>Google Maven Central</name>
            <url>https://maven-central.storage.googleapis.com
            </url>
            <mirrorOf>central</mirrorOf>
        </mirror>
        <!-- 中央仓库在中国的镜像 -->
        <mirror>
            <id>maven.net.cn</id>
            <name>oneof the central mirrors in china</name>
            <url>http://maven.net.cn/content/groups/public/</url>
            <mirrorOf>central</mirrorOf>
        </mirror>
    </mirrors>
</settings>

Maven依赖管理

<?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>org.example</groupId>
    <artifactId>untitled1</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.2.22.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-api</artifactId>
            <version>5.6.3</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>RELEASE</version>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.6</version>
        </dependency>
    </dependencies>
</project>

取得绝对路径

${pageContext.request.contextPath}

需要在web.xml文件中配置web-app高版本

<?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">
</web-app>

获取当前系统时间

            //获取当前的日期
            Date D = new Date();
            SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//设置日期格式
            String date = df.format(D);//获取String类型的时间

Servlet初始化（个人使用）

        request.setCharacterEncoding("UTF-8");
        response.setContentType("text/html; charset=utf-8");
        response.setCharacterEncoding("utf-8");
        PrintWriter out = response.getWriter();

生成随机数

Random rd = new Random();
StringBuilder rs1 = new StringBuilder();
for (int i = 0; i < 5; i++) {
            rs1.append(rd.nextInt(10));
        }

设置循环次数可以设定生成的数的数量，nextInt的参数是数字的范围，例如下面的方法

public String random_Tnum(){
        Random rd = new Random();
        StringBuilder rs1 = new StringBuilder();
        StringBuilder rs2 = new StringBuilder();
        for (int i = 0; i < 5; i++) {
            rs1.append(rd.nextInt(10));
        }
        for (int i = 0; i < 5; i++) {
            rs2.append(rd.nextInt(10));
        }
        return "T"+rs1.toString()+"S"+rs2.toString();
    }

可以生成TxxxxxSxxxxx的一段字符串