spring boot介紹及使用詳解,帶你走進spring
Spring Boot是由Pivotal團隊提供的全新框架,其設計目的是用來簡化新Spring應用的初始搭建以及開發過程。該框架使用了特定的方式來進行配置,從而使開發人員不再需要定義樣板化的配置。通過這種方式,Boot致力於在蓬勃發展的快速應用開發領域(rapid application development)成為領導者。
Spring boot的特點
1. 建立獨立的Spring應用程式
2. 嵌入的Tomcat,無需部署WAR檔案
3. 簡化Maven配置
4. 自動配置Spring
5. 提供生產就緒型功能,如指標,健康檢查和外部配置
6. 絕對沒有程式碼生成和對XML沒有要求配置
Spring boot的優點
spring boot 可以支援你快速的開發出 restful 風格的微服務架構
自動化確實方便,做微服務再合適不過了,單一jar包部署和管理都非常方便。只要系統架構設計合理,大型專案也能用,加上nginx負載均衡,輕鬆實現橫向擴充套件
spring boot 要解決的問題, 精簡配置是一方面, 另外一方面是如何方便的讓spring生態圈和其他工具鏈整合(比如redis, email, elasticsearch)
Spring boot的使用
1、maven配置檔案
<?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>
2、application類
@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); } }
3、配置類
@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) {
// 多個攔截器組成一個攔截器鏈
// addPathPatterns 用於新增攔截規則
// excludePathPatterns 使用者排除攔截
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 指定磁碟絕對路徑,同樣可以配置多個位置,注意路徑寫法需要加上file:
registry.addResourceHandler("/imgs/**").addResourceLocations("file:D:/imgs/");
super.addResourceHandlers(registry);
}
}
4、新增filter
@WebFilter(filterName="myFilter",urlPatterns="/*")
public class MyFilter implements Filter {
@Override
public void destroy() {
System.out.println("過濾器銷燬");
}
@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
System.out.println("執行過濾操作");
chain.doFilter(request, response);
}
@Override
public void init(FilterConfig config) throws ServletException {
System.out.println("過濾器初始化");
}
}
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;
}
6、service
@Service
public class HelloWorldService {
public String getHelloMessage() {
return "Hello world";
}
}
7、全域性異常處理
@ControllerAdvice
public class GlobalExceptionHandler {
@ExceptionHandler(RuntimeException.class)
@ResponseBody //在返回自定義相應類的情況下必須有,這是@ControllerAdvice註解的規定
public MyExceptionResponse exceptionHandler(RuntimeException e, HttpServletResponse response) {
return resp;
}
}
說明:
@ControllerAdvice是controller的一個輔助類,最常用的就是作為全域性異常處理的切面類
@ControllerAdvice可以指定掃描範圍
@ControllerAdvice約定了幾種可行的返回值,如果是直接返回model類的話,需要使用@ResponseBody進行json轉換
1、返回String,表示跳到某個view
2、返回modelAndView
3、返回model + @ResponseBody
8、新增被其他配置使用的bean
@Bean
public PageHelper pageHelper(DataSource dataSource) {
PageHelper pageHelper = new PageHelper();
return pageHelper;
}
9、新增資料載入類
@Component
public class MyStartupRun implements CommandLineRunner {
@Override
public void run(String... args) throws Exception {
System.out.println(">>>>>>>>>>>>>>>服務啟動執行");
}
}
該元件在專案啟動時會立即執行
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