一、JSP相关配置
JSP （Spring Boot官方不推荐，STS创建的项目会在src/main/resources 下有个templates 目录，这里就是让我们放模版文件的，然后并没有生成诸如 SpringMVC 中的webapp目录）
1、在pom.xml文件添加依赖；
<!-- tomcat 的支持.-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
<scope>provided</scope>
</dependency>
<!-- servlet 依赖. -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<scope>provided</scope>
</dependency>
<!--
JSTL（JSP Standard Tag Library，JSP标准标签库)是一个不断完善的开放源代码的JSP标签库，是由apache的jakarta小组来维护的。JSTL只能运行在支持JSP1.2和Servlet2.3规范的容器上，如tomcat 4.x。在JSP 2.0中也是作为标准支持的。
不然报异常信息：
javax.servlet.ServletException: Circular view path [/helloJsp]: would dispatch back to the current handler URL [/helloJsp] again. Check your ViewResolver setup! (Hint: This may be the result of an unspecified view, due to default view name generation.)
-->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.0.18</version>
<exclusions>
<exclusion>
<groupId>com.alibaba</groupId>
<artifactId>jconsole</artifactId>
</exclusion>
<exclusion>
<groupId>com.alibaba</groupId>
<artifactId>tools</artifactId>
</exclusion>
</exclusions>
</dependency>
jdk版本
<!-- Jdk编译版本 -->
<build>
<plugins>
<finalName>spring-boot-jsp</finalName>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
</build>
2、配置application.properties支持jsp
因为spring-boot 不推荐JSP，想使用JSP需要配置application.properties。
添加src/main/resources/application.properties内容：
# 页面默认前缀目录 spring.mvc.view.prefix=/WEB-INF/jsp/ # 响应页面默认后缀 spring.mvc.view.suffix=.jsp # 自定义属性，可以在Controller中读取 application.hello=Hello Angel From application
3、编写测试Controller
@Controller
public class IndexController {
// 从application.properties 中读取配置，如取不到默认值为Hello Shanhy
@Value("${application.hello:Hello Angel}")
private String hello;
@RequestMapping("/helloJsp")
public String helloJsp(Map<String,Object> map){
System.out.println("HelloController.helloJsp().hello="+hello);
map.put("hello", hello);
return "hello";
}
}
4、编写JSP页面
在 src/main 下面创建 webapp/WEB-INF/jsp 目录用来存放我们的jsp页面：helloJsp.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
helloJsp
<hr>
${hello}
</body>
</html>
右键Run As Java Application访问：http://127.0.0.1:8080/helloJsp 可以访问到：
helloJsp
Hello Angel From application
二、Servlet 相关配置
Web开发使用 Controller 基本上可以完成大部分需求，但是我们还可能会用到 Servlet、Filter、Listener、Interceptor 等等。
当使用Spring-Boot时，嵌入式Servlet容器通过扫描注解的方式注册Servlet、Filter和Servlet规范的所有监听器（如HttpSessionListener监听器）。
Spring boot 的主 Servlet 为 DispatcherServlet，其默认的url-pattern为“/”。也许我们在应用中还需要定义更多Servlet，该如何使用SpringBoot来完成呢？
在spring boot中添加自己的Servlet有两种方法，代码注册Servlet和注解自动注册（Filter和Listener也是如此）。
一、代码注册通过ServletRegistrationBean、 FilterRegistrationBean 和 ServletListenerRegistrationBean 获得控制。
也可以通过实现 ServletContextInitializer 接口直接注册，如下：
package com.gongh.config;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* 自定义servlet1
* @author gh
* @version v.0.1
*/
public class MyServlet1 extends HttpServlet{
static final long serialVersionUID = 1L;
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println("=====MyServlet1 doGet()======");
doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println("=====MyServlet1 doPost()======");
resp.setContentType("text/html");
PrintWriter out = resp.getWriter();
out.println("<html>");
out.println("<head>");
out.println("<title>Hello World</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>this is MyServlet1</h1>");
out.println("</body>");
out.println("</html>");
}
}
然后在App.java启动类中进行注册
@SpringBootApplication
@ServletComponentScan //是的spring能够扫描到我们自己编写的servlet和filter。
public class App extends WebMvcConfigurerAdapter{
public static void main(String[] args) {
SpringApplication.run(App.class, args);
}
@Bean
public ServletRegistrationBean MyServlet1(){
return new ServletRegistrationBean(new MyServlet1(),"/myServlet/*");
}}
右键Run As Java Application进行访问http://127.0.0.1:8080/myServlet
二、在 SpringBootApplication 上使用@ServletComponentScan注解后，Servlet、Filter、Listener 可以直接通过 @WebServlet、@WebFilter、@WebListener 注解自动注册，无需其他代码。
package com.gongh.config;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* 自定义servlet2
* @author gh
* @version v.0.1
*/
@WebServlet(urlPatterns="/myServlet2/*", description="Servlet的说明")
public class MyServlet2 extends HttpServlet{
private static final long serialVersionUID = 1L;
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println("=====MyServlet2 doGet()======");
doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println("=====MyServlet2 doPost()======");
resp.setContentType("text/html");
PrintWriter out = resp.getWriter();
out.println("<html>");
out.println("<head>");
out.println("<title>Hello World</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>this is MyServlet2</h1>");
out.println("</body>");
out.println("</html>");
}
}
右键Run As Java Application进行访问http://127.0.0.1:8080/myServlet2
