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
创建独立的Spring应用程序
嵌入的Tomcat,无需部署WAR文件
简化Maven配置
自动配置Spring
提供生产就绪型功能,如指标,健康检查和外部配置
绝对没有代码生成和对XML没有要求配置
Spring boot的优点
spring boot 可以支持你快速的开发出 restful 风格的微服务架构
自动化确实方便,做微服务再合适不过了,单一jar包部署和管理都非常方便。只要系统架构设计合理,大型项目也能用,加上nginx负载均衡,轻松实现横向扩展
spring boot 要解决的问题, 精简配置是一方面, 另外一方面是如何方便的让spring生态圈和其他工具链整合(比如redis, email, elasticsearch)
Spring boot的使用
<?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> <!-- MYSQL --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <!-- Spring Boot JDBC --> <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>
@SpringBootApplication@ServletComponentScanpublic class SpringBootApplication extends SpringBootServletInitializer { private static final Logger logger = LoggerFactory.getLogger(SpringBootSampleApplication.class); public static void main(String[] args) { SpringApplication.run(SpringBootSampleApplication.class, args); } }
@Repository@Component@Configurationpublic 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); } }
@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"); } }
@RestController@RequestMapping("/hello") public class HelloController { @RequestMapping("/info") public Map<String, String> getInfo(@RequestParam String name) { Map<String, String> map = new HashMap<>(); return map; } }
@Servicepublic class HelloWorldService { public String getHelloMessage() { return "Hello world"; } }
@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; } }
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
@Beanpublic PageHelper pageHelper(DataSource dataSource) { PageHelper pageHelper = new PageHelper(); return pageHelper; }
@Componentpublic class MyStartupRun implements CommandLineRunner { @Override public void run(String... args) throws Exception { System.out.println(">>>>>>>>>>>>>>>服务启动执行"); } }
该组件在项目启动时会立即执行