Spring Boot 整合JSP之Hello World
前半部分译自https://hellokoding.com/spring-boot-hello-world-example-with-jsp/
其实原文已经相当简单了。
本教程手把手教你如何使用SpringBoot 和 JSP来创建一个Hello World的web app样例程序。
你想要的
你所需要的
JDK 8+ or OpenJDK 8+
Maven 3+
初始化项目结构和依赖
项目结构
├── src
│ └── main
│ ├── java
│ │ └── com
│ │ └── hellokoding
│ │ └── springboot
│ │ └── view
│ │ ├── Application.java
│ │ └── HelloController.java
│ ├── resources
│ │ ├── static
│ │ │ ├── css
│ │ │ │ └── main.css
│ │ │ └── js
│ │ │ └── main.js
│ │ └── application.properties
│ └── webapp
│ └── WEB-INF
│ └── jsp
│ └── hello.jsp
└── pom.xml依赖
<?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>com.hellokoding.springboot</groupId>
<artifactId>springboot-jsp-helloworld</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.1.RELEASE</version>
</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>
<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>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>定义Controller和视图模版
Hello Controller
Controller 通过 View 映射HTTP的请求。
package com.hellokoding.springboot.view;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
@Controller
public class HelloController {
@GetMapping({"/", "/hello"})
public String hello(Model model, @RequestParam(value="name", required=false, defaultValue="World") String name) {
model.addAttribute("name", name);
return "hello";
}
}@RequestMapping 映射 /hello 请求到 hello() 方法.
name 是 /hello 请求的参数。
Model 对象传递数据到 hello 视图 (hello.jsp).
视图模版
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Hello ${name}!</title>
<link href="/css/main.css" rel="stylesheet">
</head>
<body>
<h2 class="hello-title">Hello ${name}!</h2>
<script src="/js/main.js"></script>
</body>
</html>静态文件
.hello-title{
color: darkgreen;
}(function(){
console.log("Hello World!");
})();配置和运行
应用程序配置
package com.hellokoding.springboot.view;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
@SpringBootApplication
public class Application extends SpringBootServletInitializer {
@Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
return application.sources(Application.class);
}
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}spring.mvc.view.prefix: /WEB-INF/jsp/
spring.mvc.view.suffix: .jsp通过Maven运行
在项目根目录下运行下面命令行，然后可以访问 localhost:8080
mvn clean spring-boot:run源码
以上翻译结束。
No Java Compiler avaliable错误
本文为何还没结束？因为在打包运行的时候，可能会出现No Java compiler avaliable的错误。
至于真正是否出现要看你的环境了。
错误输出：
$ mvn spring-boot:run
...
java.lang.IllegalStateException: No Java compiler available
at org.apache.jasper.JspCompilationContext.createCompiler(JspCompilationContext.java:235) ~[tomcat-embed-jasper-8.5.6.jar:8.5.6]
at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:592) ~[tomcat-embed-jasper-8.5.6.jar:8.5.6]
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:368) ~[tomcat-embed-jasper-8.5.6.jar:8.5.6]
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385) ~[tomcat-embed-jasper-8.5.6.jar:8.5.6]
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329) ~[tomcat-embed-jasper-8.5.6.jar:8.5.6]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) [tomcat-embed-core-8.5.6.jar:8.5.6]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) [tomcat-embed-core-8.5.6.jar:8.5.6]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.6.jar:8.5.6]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat-embed-websocket-8.5.6.jar:8.5.6]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) [tomcat-embed-core-8.5.6.jar:8.5.6]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.6.jar:8.5.6]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101) [spring-web-4.3.4.RELEASE.jar:4.3.4.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)解决方法：
在maven里面添加依赖
<dependency>
<groupId>org.eclipse.jdt.core.compiler</groupId>
<artifactId>ecj</artifactId>
<version>4.6.1</version>
<scope>provided</scope>
</dependency>其实通过dependies看，都依赖了，就是不知为何没有自动挂载。
解决方法来自：
https://www.mkyong.com/spring-boot/spring-boot-web-jsp-no-java-compiler-available/