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JavaEE 学习笔记 —— Spring Boot

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目录

    • Spring Boot
      • 作用(使用 Spring Boot 的目的)
      • 开发步骤
        • 关于 application.properties 配置文件常用配置

Spring Boot

作用(使用 Spring Boot 的目的)

基于 约定优于配置 的思想,省略了大量的配置(Spring Framework 会使用大量 xml 配置,且很多重复的)

开发步骤

  1. 创建普通 maven 项目
    写入 pom.xml
<?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>

    <!-- 默认使用的Spring Framework版本为5.2.10.RELEASE -->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.5.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>org.example</groupId>
    <artifactId>springboot-study</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>

        <!-- spring-boot-starter-web: 基于SpringBoot开发的依赖包,
                                 会再次依赖spring-framework中基本依赖包,aop相关依赖包,web相关依赖包,
                                 还会引入其他如json,tomcat,validation等依赖 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <!-- 排除tomcat依赖 -->
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-tomcat</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <!-- 添加 Undertow 依赖 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-undertow</artifactId>
        </dependency>

        <!--引入AOP依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>

        <!-- spring-boot-devtools: SpringBoot的热部署依赖包 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <!-- 不能被其它模块继承,如果多个子模块可以去掉 -->
            <optional>true</optional>
        </dependency>

        <!-- lombok: 简化bean代码的框架 -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

        <!-- spring-boot-starter-test: SpringBoot测试框架 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <!-- SpringBoot的maven打包插件 -->
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <!-- 明确指定一些插件的版本,以免受到 maven 版本的影响 -->
            <plugin>
                <artifactId>maven-clean-plugin</artifactId>
                <version>3.1.0</version>
            </plugin>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
            </plugin>
            <plugin>
                <artifactId>maven-deploy-plugin</artifactId>
                <version>2.8.2</version>
            </plugin>
            <plugin>
                <artifactId>maven-install-plugin</artifactId>
                <version>2.5.2</version>
            </plugin>
            <plugin>
                <artifactId>maven-jar-plugin</artifactId>
                <version>3.2.0</version>
            </plugin>
            <plugin>
                <artifactId>maven-resources-plugin</artifactId>
                <version>3.1.0</version>
            </plugin>
            <plugin>
                <artifactId>maven-site-plugin</artifactId>
                <version>3.3</version>
            </plugin>
            <plugin>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>2.22.2</version>
            </plugin>

        </plugins>
    </build>

</project>
  1. 创建启动类
    启动类一定要在 src / main / java / 某一个包 下,并非直接在 src 目录下
package org.example;


import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication  
public class SpringStudy {

    public static void main(String[] args) {
        SpringApplication.run(SpringStudy.class,args);
    }
}

  1. 创建 web 资源文件夹
    在 resource 目录下创建 public 、static 两个包,这两个包下放入的是静态资源
    后续在访问时 url 不需要加 public 或者 static

在这里插入图片描述
在这里插入图片描述
5. resource 目录下创建 Spring Boot 启动配置文件 application.properties
点击运行 启动类,正常情况下,控制台出现如下字符

"C:\Program Files\Java\jdk1.8.0_192\bin\java.exe" -Dspring.output.ansi.enabled=always "-javaagent:D:\Program Files\JetBrains\IntelliJ IDEA 2020.1.3\lib\idea_rt.jar=28748:D:\Program Files\JetBrains\IntelliJ IDEA 2020.1.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_192\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_192\jre\lib\rt.jar;D:\Users\李逍遥\IdeaProjects\spring02\target\classes;C:\Users\李逍遥\.m2\repository\org\springframework\boot\spring-boot-starter-web\2.3.5.RELEASE\spring-boot-starter-web-2.3.5.RELEASE.jar;C:\Users\李逍遥\.m2\repository\org\springframework\boot\spring-boot-starter\2.3.5.RELEASE\spring-boot-starter-2.3.5.RELEASE.jar;C:\Users\李逍遥\.m2\repository\org\springframework\boot\spring-boot-starter-logging\2.3.5.RELEASE\spring-boot-starter-logging-2.3.5.RELEASE.jar;C:\Users\李逍遥\.m2\repository\ch\qos\logback\logback-classic\1.2.3\logback-classic-1.2.3.jar;C:\Users\李逍遥\.m2\repository\ch\qos\logback\logback-core\1.2.3\logback-core-1.2.3.jar;C:\Users\李逍遥\.m2\repository\org\apache\logging\log4j\log4j-to-slf4j\2.13.3\log4j-to-slf4j-2.13.3.jar;C:\Users\李逍遥\.m2\repository\org\apache\logging\log4j\log4j-api\2.13.3\log4j-api-2.13.3.jar;C:\Users\李逍遥\.m2\repository\org\slf4j\jul-to-slf4j\1.7.30\jul-to-slf4j-1.7.30.jar;C:\Users\李逍遥\.m2\repository\jakarta\annotation\jakarta.annotation-api\1.3.5\jakarta.annotation-api-1.3.5.jar;C:\Users\李逍遥\.m2\repository\org\yaml\snakeyaml\1.26\snakeyaml-1.26.jar;C:\Users\李逍遥\.m2\repository\org\springframework\boot\spring-boot-starter-json\2.3.5.RELEASE\spring-boot-starter-json-2.3.5.RELEASE.jar;C:\Users\李逍遥\.m2\repository\com\fasterxml\jackson\core\jackson-databind\2.11.3\jackson-databind-2.11.3.jar;C:\Users\李逍遥\.m2\repository\com\fasterxml\jackson\core\jackson-annotations\2.11.3\jackson-annotations-2.11.3.jar;C:\Users\李逍遥\.m2\repository\com\fasterxml\jackson\core\jackson-core\2.11.3\jackson-core-2.11.3.jar;C:\Users\李逍遥\.m2\repository\com\fasterxml\jackson\datatype\jackson-datatype-jdk8\2.11.3\jackson-datatype-jdk8-2.11.3.jar;C:\Users\李逍遥\.m2\repository\com\fasterxml\jackson\datatype\jackson-datatype-jsr310\2.11.3\jackson-datatype-jsr310-2.11.3.jar;C:\Users\李逍遥\.m2\repository\com\fasterxml\jackson\module\jackson-module-parameter-names\2.11.3\jackson-module-parameter-names-2.11.3.jar;C:\Users\李逍遥\.m2\repository\org\springframework\spring-web\5.2.10.RELEASE\spring-web-5.2.10.RELEASE.jar;C:\Users\李逍遥\.m2\repository\org\springframework\spring-beans\5.2.10.RELEASE\spring-beans-5.2.10.RELEASE.jar;C:\Users\李逍遥\.m2\repository\org\springframework\spring-webmvc\5.2.10.RELEASE\spring-webmvc-5.2.10.RELEASE.jar;C:\Users\李逍遥\.m2\repository\org\springframework\spring-context\5.2.10.RELEASE\spring-context-5.2.10.RELEASE.jar;C:\Users\李逍遥\.m2\repository\org\springframework\spring-expression\5.2.10.RELEASE\spring-expression-5.2.10.RELEASE.jar;C:\Users\李逍遥\.m2\repository\org\springframework\boot\spring-boot-starter-undertow\2.3.5.RELEASE\spring-boot-starter-undertow-2.3.5.RELEASE.jar;C:\Users\李逍遥\.m2\repository\io\undertow\undertow-core\2.1.4.Final\undertow-core-2.1.4.Final.jar;C:\Users\李逍遥\.m2\repository\org\jboss\logging\jboss-logging\3.4.1.Final\jboss-logging-3.4.1.Final.jar;C:\Users\李逍遥\.m2\repository\org\jboss\xnio\xnio-api\3.8.0.Final\xnio-api-3.8.0.Final.jar;C:\Users\李逍遥\.m2\repository\org\wildfly\common\wildfly-common\1.5.2.Final\wildfly-common-1.5.2.Final.jar;C:\Users\李逍遥\.m2\repository\org\wildfly\client\wildfly-client-config\1.0.1.Final\wildfly-client-config-1.0.1.Final.jar;C:\Users\李逍遥\.m2\repository\org\jboss\xnio\xnio-nio\3.8.0.Final\xnio-nio-3.8.0.Final.jar;C:\Users\李逍遥\.m2\repository\org\jboss\threads\jboss-threads\3.1.0.Final\jboss-threads-3.1.0.Final.jar;C:\Users\李逍遥\.m2\repository\io\undertow\undertow-servlet\2.1.4.Final\undertow-servlet-2.1.4.Final.jar;C:\Users\李逍遥\.m2\repository\org\jboss\spec\javax\annotation\jboss-annotations-api_1.3_spec\2.0.1.Final\jboss-annotations-api_1.3_spec-2.0.1.Final.jar;C:\Users\李逍遥\.m2\repository\io\undertow\undertow-websockets-jsr\2.1.4.Final\undertow-websockets-jsr-2.1.4.Final.jar;C:\Users\李逍遥\.m2\repository\org\jboss\spec\javax\websocket\jboss-websocket-api_1.1_spec\2.0.0.Final\jboss-websocket-api_1.1_spec-2.0.0.Final.jar;C:\Users\李逍遥\.m2\repository\jakarta\servlet\jakarta.servlet-api\4.0.4\jakarta.servlet-api-4.0.4.jar;C:\Users\李逍遥\.m2\repository\org\glassfish\jakarta.el\3.0.3\jakarta.el-3.0.3.jar;C:\Users\李逍遥\.m2\repository\org\springframework\boot\spring-boot-starter-aop\2.3.5.RELEASE\spring-boot-starter-aop-2.3.5.RELEASE.jar;C:\Users\李逍遥\.m2\repository\org\springframework\spring-aop\5.2.10.RELEASE\spring-aop-5.2.10.RELEASE.jar;C:\Users\李逍遥\.m2\repository\org\aspectj\aspectjweaver\1.9.6\aspectjweaver-1.9.6.jar;C:\Users\李逍遥\.m2\repository\org\springframework\boot\spring-boot-devtools\2.3.5.RELEASE\spring-boot-devtools-2.3.5.RELEASE.jar;C:\Users\李逍遥\.m2\repository\org\springframework\boot\spring-boot\2.3.5.RELEASE\spring-boot-2.3.5.RELEASE.jar;C:\Users\李逍遥\.m2\repository\org\springframework\boot\spring-boot-autoconfigure\2.3.5.RELEASE\spring-boot-autoconfigure-2.3.5.RELEASE.jar;C:\Users\李逍遥\.m2\repository\org\projectlombok\lombok\1.18.16\lombok-1.18.16.jar;C:\Users\李逍遥\.m2\repository\org\slf4j\slf4j-api\1.7.30\slf4j-api-1.7.30.jar;C:\Users\李逍遥\.m2\repository\org\springframework\spring-core\5.2.10.RELEASE\spring-core-5.2.10.RELEASE.jar;C:\Users\李逍遥\.m2\repository\org\springframework\spring-jcl\5.2.10.RELEASE\spring-jcl-5.2.10.RELEASE.jar" org.example.SpringStudy

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.3.5.RELEASE)

2021-10-22 20:02:54.134  INFO 13528 --- [  restartedMain] org.example.SpringStudy                  : Starting SpringStudy on DESKTOP-AKHVU3E with PID 13528 (D:\Users\李逍遥\IdeaProjects\spring02\target\classes started by 李逍遥 in D:\Users\李逍遥\IdeaProjects\spring02)
2021-10-22 20:02:54.137  INFO 13528 --- [  restartedMain] org.example.SpringStudy                  : No active profile set, falling back to default profiles: default
2021-10-22 20:02:54.232  INFO 13528 --- [  restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : Devtools property defaults active! Set 'spring.devtools.add-properties' to 'false' to disable
2021-10-22 20:02:54.232  INFO 13528 --- [  restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : For additional web related logging consider setting the 'logging.level.web' property to 'DEBUG'
2021-10-22 20:02:56.646  WARN 13528 --- [  restartedMain] io.undertow.websockets.jsr               : UT026010: Buffer pool was not set on WebSocketDeploymentInfo, the default pool will be used
2021-10-22 20:02:56.676  INFO 13528 --- [  restartedMain] io.undertow.servlet                      : Initializing Spring embedded WebApplicationContext
2021-10-22 20:02:56.676  INFO 13528 --- [  restartedMain] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 2443 ms

如果出现错误,可能是 tomcat 端口(8080)被占用,此时可以在 resource 目录下的启动配置文件 application.properties 中添加如下字符(修改端口)

在这里插入图片描述

关于 application.properties 配置文件常用配置

#server.port=8888 端口被占用 修改端口


# 调试模式启动, 开发环境中, 可以看到更多的日志便于排查问题
debug=true

# 基础日志打印级别 ( 从低到高 ):
# 1. debug
# 2. info
# 3. warn
# 4. error
# 代码中, 使用 logger.debug / logger.info 打印日志, 日志级别以下的不会打印
logging.level.root=debug

# json 日期格式
spring.jackson.date-format=yyyy-MM-dd HH:mm:ss

# json 日期地区
spring.jackson.time-zone=GMT+8

# json 格式美化
spring.jackson.serialization.indent-output=true
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