spring boot: Whitelabel Error Page的解决方案

初次使用spring boot，按照其官网Building a RESTful Web Service搭建运行一个demo，代码如下:

pom.xml

[html] view plain copy print?<?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>personal.timeless</groupId>
<artifactId>CommentSystem</artifactId>
<packaging>war</packaging>
<version>0.0.1-SNAPSHOT</version>

<name>CommentSystem Maven Webapp</name>
<url>http://maven.apache.org</url>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.2.RELEASE</version>
</parent>

<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.jayway.jsonpath</groupId>
<artifactId>json-path</artifactId>
<scope>test</scope>
</dependency>
</dependencies>

<properties>
<java.version>1.8</java.version>
</properties>

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>

<repositories>
<repository>
<id>spring-releases</id>
<url>https://repo.spring.io/libs-release</url>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-releases</id>
<url>https://repo.spring.io/libs-release</url>
</pluginRepository>
</pluginRepositories>
</project>

<?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>personal.timeless</groupId>
<artifactId>CommentSystem</artifactId>
<packaging>war</packaging>
<version>0.0.1-SNAPSHOT</version>

<name>CommentSystem Maven Webapp</name>
<url>http://maven.apache.org</url>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.2.RELEASE</version>
</parent>

<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.jayway.jsonpath</groupId>
<artifactId>json-path</artifactId>
<scope>test</scope>
</dependency>
</dependencies>

<properties>
<java.version>1.8</java.version>
</properties>

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>

<repositories>
<repository>
<id>spring-releases</id>
<url>https://repo.spring.io/libs-release</url>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-releases</id>
<url>https://repo.spring.io/libs-release</url>
</pluginRepository>
</pluginRepositories>
</project>

controller Comment.java

[java] view plain copy print?import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class Comments {

@RequestMapping(“/greeting”)
public String greeting(@RequestParam(value=“name”, defaultValue=“World”) String name) {
return name;
}
}

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class Comments {

@RequestMapping("/greeting")
public String greeting(@RequestParam(value="name", defaultValue="World") String name) {
return name;
}
}

主文件 App.java

[java] view plain copy print?import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class App { public static void main(String[] args) throws Exception { SpringApplication.run(App.class, args); } }

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class App
{
public static void main(String[] args) throws Exception {
SpringApplication.run(App.class, args);
}
}

运行起来没报错，但是打开浏览器输入地址http://localhost:8080/greeting出现以下页面



检查地址没问题，核对jar包也正确。google,有说少jar包，按照回答添加以后也无济于事。折腾了一会找到了原因



竟然时目录文件结构问题，最后附上官网说明http://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/htmlsingle/#using-boot-structuring-your-code

[html] view plain copy print?14.2 Locating the main application class We generally recommend that you locate your main application class in a root package above other classes. The @EnableAutoConfiguration annotation is often placed on your main class, and it implicitly defines a base “search package” for certain items. For example, if you are writing a JPA application, the package of the @EnableAutoConfiguration annotated class will be used to search for @Entity items. Using a root package also allows the @ComponentScan annotation to be used without needing to specify a basePackage attribute. You can also use the @SpringBootApplication annotation if your main class is in the root package. Here is a typical layout: com +- example +- myproject +- Application.java | +- domain | +- Customer.java | +- CustomerRepository.java | +- service | +- CustomerService.java | +- web +- CustomerController.java

14.2 Locating the main application class
We generally recommend that you locate your main application class in a root package above other classes. The @EnableAutoConfiguration annotation is often placed on your main class, and it implicitly defines a base “search package” for certain items. For example, if you are writing a JPA application, the package of the @EnableAutoConfiguration annotated class will be used to search for @Entity items.

Using a root package also allows the @ComponentScan annotation to be used without needing to specify a basePackage attribute. You can also use the @SpringBootApplication annotation if your main class is in the root package.

Here is a typical layout:

com
+- example
+- myproject
+- Application.java
|
+- domain
|   +- Customer.java
|   +- CustomerRepository.java
|
+- service
|   +- CustomerService.java
|
+- web
+- CustomerController.java

</div>