不支持请求方法'HEAD'

Question

我用apache tomcat 7.0.55运行了Intellij Idea的一个新实例，我创建了一个新的简单项目，但我不断地收到以下错误：

Feb 28, 2015 11:54:13 PM org.springframework.web.servlet.PageNotFound handleHttpRequestMethodNotSupported
WARNING: Request method 'HEAD' not supported

控制器：

package com.springapp.mvc;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
@Controller
@RequestMapping(value="/",method = {RequestMethod.GET, RequestMethod.HEAD})
public class HelloController {
    @RequestMapping(method = RequestMethod.GET)
    public String printWelcome(ModelMap model) {
        model.addAttribute("message", "Hello world!");
        return "hello";
    }
}

pom.xml

<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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.springapp</groupId>
    <artifactId>untitled</artifactId>
    <packaging>war</packaging>
    <version>1.0-SNAPSHOT</version>
    <name>untitled</name>
    <properties>
        <spring.version>4.1.1.RELEASE</spring.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.1</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <build>
        <finalName>untitled</finalName>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.6</source>
                    <target>1.6</target>
                </configuration>
            </plugin>
            <plugin>
                <artifactId>maven-surefire-plugin</artifactId>
                <configuration>
                    <includes>
                        <include>**/*Tests.java</include>
                    </includes>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Answer 1

在类级别，使用

@RequestMapping(value="/",method = {RequestMethod.GET, RequestMethod.HEAD})
public class HelloController {

您声明您的控制器将处理对根URL /的GET和HEAD请求。

但在方法层面，

@RequestMapping(method = RequestMethod.GET)

您只接受GET请求。Spring是对的，请求方法'HEAD'不受支持。

您应该在方法级别（@RequestMapping(value = "")）接受所有内容，或者创建第二个方法来处理HEAD请求。

Answer 2

在最近的春季版本中，GET方法隐式添加了HEAD方法。

@GetMapping (and @RequestMapping(method=HttpMethod.GET)) are implicitly mapped to and support HTTP HEAD. An HTTP HEAD request is processed as if it were HTTP GET except that, instead of writing the body, the number of bytes are counted and the Content-Length header is set.有关更多详细信息，请参阅：https://docs.spring.io/spring-framework/reference/web/webmvc/mvc-controller/ann-requestmapping.html#mvc-ann请求映射头选项