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

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print ?

1. <?xml version=“1.0” encoding=“UTF-8”?>  
2. <project xmlns=“http://maven.apache.org/POM/4.0.0” xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”  
3.     xsi:schemaLocation=“http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd”>  
4.     <modelVersion>4.0.0</modelVersion>  
5.       
6.     <groupId>personal.timeless</groupId>  
7.     <artifactId>CommentSystem</artifactId>  
8.     <packaging>war</packaging>  
9.     <version>0.0.1-SNAPSHOT</version>  
10.       
11.     <name>CommentSystem Maven Webapp</name>  
12.     <url>http://maven.apache.org</url>  
13.       
14.     <parent>  
15.         <groupId>org.springframework.boot</groupId>  
16.         <artifactId>spring-boot-starter-parent</artifactId>  
17.         <version>1.4.2.RELEASE</version>  
18.     </parent>  
19.   
20.     <dependencies>  
21.         <dependency>  
22.             <groupId>org.springframework.boot</groupId>  
23.             <artifactId>spring-boot-starter-web</artifactId>  
24.         </dependency>  
25.         <dependency>  
26.             <groupId>org.springframework.boot</groupId>  
27.             <artifactId>spring-boot-starter-test</artifactId>  
28.             <scope>test</scope>  
29.         </dependency>  
30.         <dependency>  
31.             <groupId>com.jayway.jsonpath</groupId>  
32.             <artifactId>json-path</artifactId>  
33.             <scope>test</scope>  
34.         </dependency>  
35.     </dependencies>  
36.   
37.     <properties>  
38.         <java.version>1.8</java.version>  
39.     </properties>  
40.   
41.   
42.     <build>  
43.         <plugins>  
44.             <plugin>  
45.                 <groupId>org.springframework.boot</groupId>  
46.                 <artifactId>spring-boot-maven-plugin</artifactId>  
47.             </plugin>  
48.         </plugins>  
49.     </build>  
50.   
51.     <repositories>  
52.         <repository>  
53.             <id>spring-releases</id>  
54.             <url>https://repo.spring.io/libs-release</url>  
55.         </repository>  
56.     </repositories>  
57.     <pluginRepositories>  
58.         <pluginRepository>  
59.             <id>spring-releases</id>  
60.             <url>https://repo.spring.io/libs-release</url>  
61.         </pluginRepository>  
62.     </pluginRepositories>  
63. </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 ?

1. import org.springframework.web.bind.annotation.RequestMapping;  
2. import org.springframework.web.bind.annotation.RequestParam;  
3. import org.springframework.web.bind.annotation.RestController;  
4.   
5. @RestController  
6. public class Comments {  
7.       
8.     @RequestMapping(“/greeting”)  
9.     public String greeting(@RequestParam(value=“name”, defaultValue=“World”) String name) {  
10.         return name;  
11.     }  
12. }  

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 ?

1. import org.springframework.boot.SpringApplication;  
2. import org.springframework.boot.autoconfigure.SpringBootApplication;  
3.   
4. @SpringBootApplication  
5. public class App  
6. {  
7.     public static void main(String[] args) throws Exception {  
8.         SpringApplication.run(App.class, args);  
9.     }  
10. }  

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 ?

1. 14.2 Locating the main application class  
2. 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.  
3.   
4. 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.  
5.   
6. Here is a typical layout:  
7.   
8. com  
9.  +- example  
10.      +- myproject  
11.          +- Application.java  
12.          |  
13.          +- domain  
14.          |   +- Customer.java  
15.          |   +- CustomerRepository.java  
16.          |  
17.          +- service  
18.          |   +- CustomerService.java  
19.          |  
20.          +- web  
21.              +- 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>

          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 ?

1. <?xml version=“1.0” encoding=“UTF-8”?>  
2. <project xmlns=“http://maven.apache.org/POM/4.0.0” xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”  
3.     xsi:schemaLocation=“http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd”>  
4.     <modelVersion>4.0.0</modelVersion>  
5.       
6.     <groupId>personal.timeless</groupId>  
7.     <artifactId>CommentSystem</artifactId>  
8.     <packaging>war</packaging>  
9.     <version>0.0.1-SNAPSHOT</version>  
10.       
11.     <name>CommentSystem Maven Webapp</name>  
12.     <url>http://maven.apache.org</url>  
13.       
14.     <parent>  
15.         <groupId>org.springframework.boot</groupId>  
16.         <artifactId>spring-boot-starter-parent</artifactId>  
17.         <version>1.4.2.RELEASE</version>  
18.     </parent>  
19.   
20.     <dependencies>  
21.         <dependency>  
22.             <groupId>org.springframework.boot</groupId>  
23.             <artifactId>spring-boot-starter-web</artifactId>  
24.         </dependency>  
25.         <dependency>  
26.             <groupId>org.springframework.boot</groupId>  
27.             <artifactId>spring-boot-starter-test</artifactId>  
28.             <scope>test</scope>  
29.         </dependency>  
30.         <dependency>  
31.             <groupId>com.jayway.jsonpath</groupId>  
32.             <artifactId>json-path</artifactId>  
33.             <scope>test</scope>  
34.         </dependency>  
35.     </dependencies>  
36.   
37.     <properties>  
38.         <java.version>1.8</java.version>  
39.     </properties>  
40.   
41.   
42.     <build>  
43.         <plugins>  
44.             <plugin>  
45.                 <groupId>org.springframework.boot</groupId>  
46.                 <artifactId>spring-boot-maven-plugin</artifactId>  
47.             </plugin>  
48.         </plugins>  
49.     </build>  
50.   
51.     <repositories>  
52.         <repository>  
53.             <id>spring-releases</id>  
54.             <url>https://repo.spring.io/libs-release</url>  
55.         </repository>  
56.     </repositories>  
57.     <pluginRepositories>  
58.         <pluginRepository>  
59.             <id>spring-releases</id>  
60.             <url>https://repo.spring.io/libs-release</url>  
61.         </pluginRepository>  
62.     </pluginRepositories>  
63. </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 ?

1. import org.springframework.web.bind.annotation.RequestMapping;  
2. import org.springframework.web.bind.annotation.RequestParam;  
3. import org.springframework.web.bind.annotation.RestController;  
4.   
5. @RestController  
6. public class Comments {  
7.       
8.     @RequestMapping(“/greeting”)  
9.     public String greeting(@RequestParam(value=“name”, defaultValue=“World”) String name) {  
10.         return name;  
11.     }  
12. }  

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 ?

1. import org.springframework.boot.SpringApplication;  
2. import org.springframework.boot.autoconfigure.SpringBootApplication;  
3.   
4. @SpringBootApplication  
5. public class App  
6. {  
7.     public static void main(String[] args) throws Exception {  
8.         SpringApplication.run(App.class, args);  
9.     }  
10. }  

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 ?

1. 14.2 Locating the main application class  
2. 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.  
3.   
4. 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.  
5.   
6. Here is a typical layout:  
7.   
8. com  
9.  +- example  
10.      +- myproject  
11.          +- Application.java  
12.          |  
13.          +- domain  
14.          |   +- Customer.java  
15.          |   +- CustomerRepository.java  
16.          |  
17.          +- service  
18.          |   +- CustomerService.java  
19.          |  
20.          +- web  
21.              +- 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>