spring boot介绍及使用详解

亦凉 2022-10-01 08:47 179阅读 0赞

Spring Boot是由Pivotal团队提供的全新框架，其设计目的是用来简化新Spring应用的初始搭建以及开发过程。该框架使用了特定的方式来进行配置，从而使开发人员不再需要定义样板化的配置。通过这种方式，Boot致力于在蓬勃发展的快速应用开发领域（rapid application development）成为领导者。

**Spring boot的特点**

1. 创建独立的Spring应用程序  
2. 嵌入的Tomcat，无需部署WAR文件  
3. 简化Maven配置  
4. 自动配置Spring  
5. 提供生产就绪型功能，如指标，健康检查和外部配置  
6. 绝对没有代码生成和对XML没有要求配置

**Spring boot的使用**

1、maven配置文件

>     <?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.springboot.sample</groupId>
>     	<artifactId>spring-boot-sample</artifactId>
>     	<version>0.0.1-SNAPSHOT</version>
>     	<packaging>war</packaging>
>     	<name>spring-boot-sample</name>
>     	<description>Spring Boot Sample Web Application</description>
>     	<parent>
>     		<groupId>org.springframework.boot</groupId>
>     		<artifactId>spring-boot-starter-parent</artifactId>
>     		<version>1.3.2.RELEASE</version>
>     		<relativePath /> 
>     	</parent>
>     	<properties>
>     		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
>     		<java.version>1.8</java.version>
>     	</properties>
>     	<dependencies>
>     		<dependency>
>     			<groupId>org.springframework.boot</groupId>
>     			<artifactId>spring-boot-starter-web</artifactId>
>     		</dependency>
>     		
>     		<dependency>
>     			<groupId>mysql</groupId>
>     			<artifactId>mysql-connector-java</artifactId>
>     		</dependency>
>     		
>     		<dependency>
>     			<groupId>org.springframework.boot</groupId>
>     			<artifactId>spring-boot-starter-jdbc</artifactId>
>     		</dependency>
>     		<dependency>
>     			<groupId>org.springframework.boot</groupId>
>     			<artifactId>spring-boot-configuration-processor</artifactId>
>     			<optional>true</optional>
>     		</dependency>
>     	</dependencies>
>     	<build>
>     		<plugins>
>     			<plugin>
>     				<groupId>org.springframework.boot</groupId>
>     				<artifactId>spring-boot-maven-plugin</artifactId>
>     			</plugin>
>     		</plugins>
>     	</build>
>     </project>
>     
>     复制代码

**2、application类**

@SpringBootApplication
    @ServletComponentScan
    public class SpringBootApplication extends SpringBootServletInitializer {
     
    	private static final Logger logger = LoggerFactory.getLogger(SpringBootSampleApplication.class);
        public static void main(String[] args) {
    		SpringApplication.run(SpringBootSampleApplication.class, args);
    	}
    }
    复制代码

**3、配置类**

@Repository
    @Component
    @Configuration
    public class MyWebAppConfigurer extends WebMvcConfigurerAdapter implements EnvironmentAware{
    	private static final Logger logger = LoggerFactory.getLogger(MyWebAppConfigurer.class);
    	private RelaxedPropertyResolver propertyResolver;
    	@Override
    	public void addInterceptors(InterceptorRegistry registry) {
    		// 多个拦截器组成一个拦截器链
    		// addPathPatterns 用于添加拦截规则
    		// excludePathPatterns 用户排除拦截
    		registry.addInterceptor(new MyInterceptor1()).addPathPatterns("/**");
    		registry.addInterceptor(new MyInterceptor2()).addPathPatterns("/**");
    		super.addInterceptors(registry);
    	}
    	@Override
    	public void addResourceHandlers(ResourceHandlerRegistry registry) {
    		registry.addResourceHandler("/res/**").addResourceLocations("classpath:/res/");
    		// 可以直接使用addResourceLocations 指定磁盘绝对路径，同样可以配置多个位置，注意路径写法需要加上file:
    		registry.addResourceHandler("/imgs/**").addResourceLocations("file:D:/imgs/");
    		super.addResourceHandlers(registry);
    	}
    }
    
    复制代码

**4、添加filter**

@WebFilter(filterName="myFilter",urlPatterns="/*")
    public class MyFilter implements Filter {
        @Override
        public void destroy() {
            System.out.println("过滤器销毁");
        }
        @Override
        public void doFilter(ServletRequest request, ServletResponse response,
                FilterChain chain) throws IOException, ServletException {
            System.out.println("执行过滤操作");	
            chain.doFilter(request, response);
        }
        @Override
        public void init(FilterConfig config) throws ServletException {
            System.out.println("过滤器初始化");
        }
    }
    复制代码

**5、controller**

@RestController
    @RequestMapping("/hello")
    public class HelloController {
    	@RequestMapping("/info")
    	public Map<String, String> getInfo(@RequestParam String name) {
    		Map<String, String> map = new HashMap<>();
    		return map;
    	}	
    }
    复制代码

**6、service**

@Service
    public class HelloWorldService {
    	public String getHelloMessage() {
    		return "Hello world";
    	}
    }
    复制代码

**7、全局异常处理**

@ControllerAdvice
     public class GlobalExceptionHandler {
         @ExceptionHandler(RuntimeException.class)
         @ResponseBody //在返回自定义相应类的情况下必须有，这是@ControllerAdvice注解的规定
         public MyExceptionResponse exceptionHandler(RuntimeException e, HttpServletResponse response) {
           
             return resp;
         }
     }
    复制代码

说明：

@ControllerAdvice是controller的一个辅助类，最常用的就是作为全局异常处理的切面类

@ControllerAdvice可以指定扫描范围

@ControllerAdvice约定了几种可行的返回值，如果是直接返回model类的话，需要使用@ResponseBody进行json转换

1、返回String，表示跳到某个view

2、返回modelAndView

3、返回model + @ResponseBody

8、添加被其他配置使用的bean

@Bean
    public PageHelper pageHelper(DataSource dataSource) {
    	PageHelper pageHelper = new PageHelper();
    	return pageHelper;
    }
    复制代码

**9、添加数据加载类**

@Component
    public class MyStartupRun implements CommandLineRunner {
        @Override
        public void run(String... args) throws Exception {
            System.out.println(">>>>>>>>>>>>>>>服务启动执行");
        }
    }
    复制代码

**该组件在项目启动时会立即执行**

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转载于:https://juejin.im/post/5ccd3de751882540e974b2a3