1蝌戒、什么是Spring Boot？使用Spring Boot有什么好處战转？
Spring Boot是基于Spring框架的快速開發(fā)整合包痛黎。
1）編碼變得簡單
快速搭建項目予弧，無需編寫繁瑣的配置文件；
2）配置變得簡單
遵循"習(xí)慣優(yōu)于配置"原則,使用Spirng Boot只需很少的配置,大部分時候可以使用默認(rèn)配置;
3）部署變得簡單
內(nèi)嵌Tomcat容器,項目部署可以直接用jar包運行(java -jar)湖饱；
4）監(jiān)控變得簡單
Spring Boot 提供基于 http掖蛤、ssh、telnet 對運行時的項目進行監(jiān)控井厌。
2蚓庭、SpringBoot中默認(rèn)配置文件有幾種格式致讥，以及有哪些區(qū)別?
有.yaml和.properties兩種文件格式。
1）.yaml是key:value的形式器赞，.properties是key=value的形式垢袱，.yaml更加簡潔明了，查看更加形象港柜；
2）.yaml中加載的屬性是有順序的请契，properties中的數(shù)據(jù)是無序的。在一些需要路徑匹配的的配置中夏醉，順序就顯得尤為重要爽锥，此時我們一般采用.yaml。
3畔柔、SpringBoot讀取配置文件的方式有哪幾種?
1）使用注解@Value進行獲取
先在application.properties中配置屬性
book.author=石紅英
然后在controller類氯夷，調(diào)用屬性，通過@Value修飾的變量會和book.author映射起來
@Controller
public class HelloController {
@Value("${book.author}")
private String name;
@ResponseBody
@RequestMapping("testConfigM1")
public String testConfigM1(ModelMap modelMap) {
return name;
}
}
2）使用bean封裝
先在application.properties配置屬性
student.name=你真漂亮
student.age=25
定義一個bean靶擦，@ConfigurationProperties(prefix = "student")將配置文件的值映射到類上使用腮考，prefix = "student"表示映射前綴是student
@Component
@ConfigurationProperties(prefix = "student")
public class StudentProperties {
private String name;
private Integer age;
// 省略get,set方法
}
然后在controller類，注入bean
@Controller
public class HelloController {
@Autowired
private StudentProperties studentProperties;
@ResponseBody
@RequestMapping("testConfigM2")
public String testConfigM2(){
System.out.println(studentProperties.getName()+"-----"+studentProperties.getAge());
return studentProperties.getName();
}
}
3）使用Environment進行獲取
先在application.properties配置屬性
name2=白骨精
然后在controller類奢啥，注入Environment類
@Controller
public class HelloController {
@Autowired
private Environment environment;
@ResponseBody
@RequestMapping("testConfigM3")
public String testConfigM3(){
return environment.getProperty("name2");
}
}
4秸仙、SpringBoot如何配置多套不同的攔截配置?
SpringBoot的攔截器實現(xiàn)和SpringMVC一致嘴拢，通過配置把攔截器注入到Spring容器中去; 但配置方式不一樣：
1）新建兩個攔截器類
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@Component
public class MyInterceptor implements HandlerInterceptor {
private static final Logger LOG= LoggerFactory.getLogger(MyInterceptor.class);
@Override
public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
LOG.info("執(zhí)行攔截器的preHandle方法");
return true;
}
@Override
public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
LOG.info("執(zhí)行攔截器的postHandle方法");
}
@Override
public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
LOG.info("執(zhí)行攔截器的afterCompletion方法");
}
}
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@Component
public class MyInterceptorTwo implements HandlerInterceptor {
private static final Logger LOG= LoggerFactory.getLogger(MyInterceptor.class);
@Override
public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
LOG.info("執(zhí)行攔截器的preHandle方法");
return true;
}
@Override
public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
LOG.info("執(zhí)行攔截器的postHandle方法");
}
@Override
public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
LOG.info("執(zhí)行攔截器的afterCompletion方法");
}
}
2）攔截器配置類
import com.jd.m.tg.interceptor.MyInterceptor;
import com.jd.m.tg.interceptor.MyInterceptorTwo;
import lombok.AllArgsConstructor;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
@Configuration
@AllArgsConstructor
public class InterceptorConfig extends WebMvcConfigurerAdapter{
private MyInterceptor myInterceptor;
private MyInterceptorTwo myInterceptorTwo;
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(myInterceptorTwo).addPathPatterns("/test/**");
registry.addInterceptor(myInterceptor).addPathPatterns("/test/**");
}
}
攔截器的添加順序就是執(zhí)行順序桩盲，攔截器執(zhí)行順序第一個是myInterceptorTwo，第二個是myInterceptor席吴。
5赌结、如何啟動一個SpringBoot項目以及需要添加什么注解?
直接像運行Java程序一樣運行啟動類就可以了。
啟動類就相當(dāng)于我們Java程序的main方法孝冒， 而啟動類中會用到一個關(guān)鍵的注解--@SpringBootApplication柬姚，@SpringBootApplication標(biāo)注這個類是屬于SpringBoot的啟動類，從源代碼中可以獲悉庄涡，這個注解被@Configuration量承、@EnableAutoConfiguration、@ComponentScan 注解所修飾穴店，換言之 Springboot 提供了統(tǒng)一的注解來替代以上三個注解撕捍。
6、SpringBoot是否需要一個獨立的web容器來運行?
不需要泣洞，Spring Boot有內(nèi)嵌的Tomcat服務(wù)器忧风，不過要注意的是，當(dāng)你打war包部署在服務(wù)器上的Tomcat的時候球凰，要記得去除Spring Boot自帶的Tomcat服務(wù)器狮腿。
未完待續(xù)
