Java - Spring boot - （初嗅）

发布日期：2021-06-30 19:50:48 浏览次数：2 分类：技术文章

本文共 9061 字，大约阅读时间需要 30 分钟。

基础概念

1. 依赖注入(DI)

ApplicationContext Spring IOC 容器负责创建Bean和维护Bean之间的依赖关系

2. 控制反转(IOC)

通过容器来实现对象组件的装配和管理,是通过依赖注入实现的

3. 注解配置

3.1 声明

@Component

@Service

@Repository

@Controller

3.2 注入

@Autowired

@Inject

@Resource

4. Java 配置

4.1 概念

Spring 4.x 推荐使用Java 配置

@Configuration,相当与Spring配置的xml文件

@Bean,当前方法返回值为一个Bean

4.2 原则

全局配置使用Java 配置

业务Bean使用注解配置

4.3. AOP

@Aspect

@After, @Before, @Around

Spring 常用配置

1. @Scope 新建Bean 的实例

2. @Value Spring EL,注入资源

3. 事件

自定义事件,ApplicationEvent

事件监听器, ApplicationListener

容器发布事件

4. @Profile,实例化不同的Bean

Spring 高级

1. 多线程

使用ThreadPoolTaskExecutor 实现一个基于线程池的TaskExecutor,然后@EnableAsync开启异步支持并通过Bean中的@Async注解来声明一个异步任务

2. 计划任务

@EnableScheduling 开启对计划任务的支持

@Scheduled, 声明计划任务

3. 条件注解,@Conditional,根据满足某一个特定条件创建一个特定的Bean

4. 组合注解与元注解

元注解,最原来的注解

组合注解,多个元注解注解后的注解,应用到Bean

Spring Boot 基础概念

独立运行Spring 项目，只需要java -jar xxx.jar

内嵌Servlet 容器，无需使用war包部署

使用starter 简化maven 配置

提供基于http, ssh, telnet 对项目进行监控

无代码生成和xml配置

Hello Spring Boot ！

1. pom.xml


      
     
      4.0.0
       
     
      peerslee
       
     
      yierling
       
     
      0.0.1-SNAPSHOT
       
     
      jar
       
     
      yierling
       
     
      http://maven.apache.org
       
       
         
      
       org.springframework.boot
          
      
       spring-boot-starter-parent
          
      
       1.3.3.RELEASE
        
       
       	
      
       1.8
          
      
       UTF-8
        
       
     	
      	
      	    
       
        org.springframework.boot
       	    
       
        spring-boot-starter-web
       	
      	
      	
      	    
       
        junit
       	    
       
        junit
       	
        
       
       
         
            
               
        
         org.springframework.boot
                
        
         spring-boot-maven-plugin

2. App.Java

package peerslee.yierling;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;/** * Hello world! * */@RestController@SpringBootApplication //Spring Boot 项目和核心注解，开启自动配置public class App {	@RequestMapping("/")	String index() {		return "Hello Spring Boot！";	}    public static void main( String[] args ) throws Exception    {        SpringApplication.run(App.class, args);    }}

3. Run

.   ____          _            __ _ _ /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ \\/  ___)| |_)| | | | | || (_| |  ) ) ) )  '  |____| .__|_| |_|_| |_\__, | / / / / =========|_|==============|___/=/_/_/_/ :: Spring Boot ::        (v1.3.3.RELEASE)2017-06-04 15:28:13.006  INFO 7312 --- [           main] peerslee.yierling.App                    : Starting App on WIN10-703302300 with PID 7312 (D:\code\eclipse\yierling\target\classes started by Administrator in D:\code\eclipse\yierling)2017-06-04 15:28:13.008  INFO 7312 --- [           main] peerslee.yierling.App                    : No active profile set, falling back to default profiles: default2017-06-04 15:28:13.052  INFO 7312 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@df27fae: startup date [Sun Jun 04 15:28:13 CST 2017]; root of context hierarchy2017-06-04 15:28:13.575  INFO 7312 --- [           main] o.s.b.f.s.DefaultListableBeanFactory     : Overriding bean definition for bean 'beanNameViewResolver' with a different definition: replacing [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration.class]] with [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter.class]]2017-06-04 15:28:14.039  INFO 7312 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)2017-06-04 15:28:14.091  INFO 7312 --- [           main] o.apache.catalina.core.StandardService   : Starting service Tomcat2017-06-04 15:28:14.092  INFO 7312 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.0.322017-06-04 15:28:14.191  INFO 7312 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext2017-06-04 15:28:14.191  INFO 7312 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1142 ms2017-06-04 15:28:14.445  INFO 7312 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean        : Mapping servlet: 'dispatcherServlet' to [/]2017-06-04 15:28:14.451  INFO 7312 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'characterEncodingFilter' to: [/*]2017-06-04 15:28:14.452  INFO 7312 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]2017-06-04 15:28:14.452  INFO 7312 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'httpPutFormContentFilter' to: [/*]2017-06-04 15:28:14.452  INFO 7312 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean  : Mapping filter: 'requestContextFilter' to: [/*]2017-06-04 15:28:14.672  INFO 7312 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@df27fae: startup date [Sun Jun 04 15:28:13 CST 2017]; root of context hierarchy2017-06-04 15:28:14.722  INFO 7312 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/]}" onto java.lang.String peerslee.yierling.App.index()2017-06-04 15:28:14.725  INFO 7312 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity
    
     
      > org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)2017-06-04 15:28:14.725  INFO 7312 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)2017-06-04 15:28:14.746  INFO 7312 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]2017-06-04 15:28:14.746  INFO 7312 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]2017-06-04 15:28:14.778  INFO 7312 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]2017-06-04 15:28:14.861  INFO 7312 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup2017-06-04 15:28:14.929  INFO 7312 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)2017-06-04 15:28:14.934  INFO 7312 --- [           main] peerslee.yierling.App                    : Started App in 2.134 seconds (JVM running for 2.432)2017-06-04 15:28:36.706  INFO 7312 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring FrameworkServlet 'dispatcherServlet'2017-06-04 15:28:36.707  INFO 7312 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization started2017-06-04 15:28:36.721  INFO 7312 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization completed in 14 ms

4. 测试

http://localhost:8080/

问题

1. 使用maven 更新项目

Project configuration is not up-to-date with pom.xml. Select: Maven->Update Project... from the project context menu or use Quick Fix.	yierling		line 1	Maven Configuration Problem

2. localhost:8080拒绝访问解决方案（win10系统）

打开“我的电脑”，选择左上角的“计算机”中的“卸载或更改程序”。

点击“启用或关闭Windows功能”。

选中“Internet Information Service”

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