1、Springboot開發，第一天
阿新 • • 發佈：2019-10-08
SpringBoot學習，第一天
目錄：1、springboot入門 2、springboot整合servlet 3、springboot整合filter
一、springboot入門
• Spring Boot設計目的是用來簡化新 Spring 應用的初始搭建以及開發過程。
• 嵌入的 Tomcat，無需部署 WAR 檔案
• Spring Boot 並不是對 Spring 功能上的增強，而是提供了一種快速使用 Spring 的方式。
POM.xml
<!--springboot專案的父類，所有springboot專案都必須繼承於它--> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.9.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <!--springboot啟動器--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency>
springBoot啟動器其實就是一些jar包的集合。SprigBoot一共提供44啟動器。
1 spring-boot-starter-web
支援全棧式的web開發，包括了romcat和springMVC等jar
2 spring-boot-starter-jdbc
支援spring以jdbc方式操作資料庫的jar包的集合
3 spring-boot-starter-redis
支援redis鍵值儲存的資料庫操作
Controller
package com.lee.controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import java.util.HashMap; import java.util.Map; @RestController public class HelloWorld { @RequestMapping("/hello") public Map<String,Object> hello(){ Map<String,Object> resultMap = new HashMap<>(); resultMap.put("msg","hello world"); return resultMap; } }
啟動類
package com.lee; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class SpringbootApplication { public static void main(String[] args) { SpringApplication.run(SpringbootApplication.class, args); } }
@SpringBootApplication包含：
@SpringBootConfiguration、@EnableAutoConfiguration、@ComponentScan、@Configuration等註解，它是一個配置類,掃描了當前包和當前包下所有子包下的所有檔案
**結果：**http://localhost:8080/hello
{"msg":"hello world"}
二、Springboot整合Servlet
兩種方式完成元件的註冊：
1、通過註解掃描完成元件的註冊
FirstServlet
package com.lee.servlet;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
/**
* springboot整合servlet的第一種方式：
* 原來
* <servlet>
* <servlet-name>firstServlet</servlet-name>
* <servlet-class>com.lee.FirstServlet</servlet-class>
* </servlet>
* <servlet-mapping>
* <servlet-name>firstServlet</servlet-name>
* <url-pattern>/firstServlet</url-pattern>
* </servlet-mapping>
*/
@WebServlet(name="firstServlet",urlPatterns = "/firstServlet")
public class FirstServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doPost(req,resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println("firstServlet............");
}
}
啟動類：
package com.lee;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;
//該註解會掃描當前包和其子包下的 @WebServlet,
//並在啟動類啟動的時候將其例項化
@ServletComponentScan
@SpringBootApplication
public class SpringbootApplicationServlet1 {
public static void main(String[] args) {
SpringApplication.run(SpringbootApplicationServlet1.class,args);
}
}
**結果：**http://localhost:8080/firstServlet
firstServlet............
2、通過方法完成元件的註冊
SecondServlet
package com.lee.servlet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class SecondServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println("secondServlet....");
}
}
啟動類
package com.lee;
import com.lee.servlet.SecondServlet;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
@SpringBootApplication
public class SpringbootApplicationServlet2 {
public static void main(String[] args) {
SpringApplication.run(SpringbootApplicationServlet2.class,args);
}
//將scondServlet註冊到servletRegistrationBean中
@Bean
public ServletRegistrationBean secondServlet(){
ServletRegistrationBean bean = new ServletRegistrationBean();
bean.setServlet(new SecondServlet());
bean.addUrlMappings("/secondServlet");
return bean;
}
}
**結果：**http://localhost:8080/secondServlet
secondServlet....
三、Springboot整合Filter
兩種方式完成元件的註冊
1、通過註解掃描完成元件的註冊
FirstFilter
package com.lee.filter;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;
/**
* <filter>
* <filter-name>FirstFilter</filter-name>
* <filter-class>com.lee.filter.FirstFilter</filter-class>
* </filter>
* <filter-mapping>
* <filter-name>FirstFilter</filter-name>
* <url-patter>/firstServlet</url-patter>
* </filter-mapping>
*/
//@WebFilter(filterName = "firstFilter",urlPatterns = {"*.do","*.action"})
@WebFilter(filterName = "firstFilter",urlPatterns = "/firstServlet")
public class FirstFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
System.out.println(" first filter init");
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
System.out.println("enter first filter");
filterChain.doFilter(servletRequest, servletResponse);
System.out.println("leave first filter");
}
@Override
public void destroy() {
System.out.println(" first filter destroy");
}
}
啟動類
package com.lee;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;
//該註解會掃描當前包和其子包下的 @WebServlet @WebFilter等,
//並在啟動類啟動的時候將其例項化
@ServletComponentScan
@SpringBootApplication
public class SpringbootApplicationFilter1 {
public static void main(String[] args) {
SpringApplication.run(SpringbootApplicationFilter1.class,args);
}
}
**結果：**http://localhost:8080/firstServlet
first filter init
enter first filter
firstServlet............
leave first filter
2、通過方法完成元件的註冊
SecondFilter
package com.lee.filter;
import javax.servlet.*;
import java.io.IOException;
public class SecondFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
System.out.println(" second filter init");
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
System.out.println("enter second filter");
filterChain.doFilter(servletRequest, servletResponse);
System.out.println("leave second filter");
}
@Override
public void destroy() {
System.out.println(" second filter destroy");
}
}
啟動類
package com.lee;
import com.lee.filter.SecondFilter;
import com.lee.servlet.SecondServlet;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
@SpringBootApplication
public class SpringbootApplicationFilter2 {
public static void main(String[] args) {
SpringApplication.run(SpringbootApplicationFilter2.class,args);
}
//將scondServlet註冊到servletRegistrationBean中
@Bean
public ServletRegistrationBean secondServlet(){
ServletRegistrationBean bean = new ServletRegistrationBean();
bean.setServlet(new SecondServlet());
bean.addUrlMappings("/secondServlet");
return bean;
}
@Bean
public FilterRegistrationBean secondFilter(){
FilterRegistrationBean bean = new FilterRegistrationBean();
bean.setFilter(new SecondFilter());
bean.addUrlPatterns("/secondServlet");
return bean;
}
}
結果：
second filter init
enter second filter
secondServlet....
leave se