Spring引导始终返回404错误

Question

我正在尝试使用一个简单的Hello world消息来响应Spring Boot（1.5.9）项目。但是，我发送的任何请求都会立即返回404异常。

MyBackendApplication

package net.mypackage.backend;

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

@SpringBootApplication
public class MyBackendApplication {

    public static void main(String[] args) {
        SpringApplication.run(MyBackendApplication.class, args);
    }
}

控制器/ HelloController中

package net.mypackage.backend.controllers;

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

@RestController
public class HelloController {

    @RequestMapping("/hello")
    public String sayHello() {
        return "Hello, world!";
    }

}

application.properties

server.port = 5000
server.contextPath=/
logging.level.org=DEBUG

的build.gradle

buildscript {
    ext {
        springBootVersion = '1.5.9.RELEASE'
    }
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
    }
}

apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'

group = 'net.mypackage'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8

repositories {
    mavenCentral()
}


dependencies {
    compile('org.springframework.boot:spring-boot-starter-jersey')
    runtime('org.springframework.boot:spring-boot-devtools')
    testCompile('org.springframework.boot:spring-boot-starter-test')
    compile("org.springframework.boot:spring-boot-starter-actuator")
}

请求页面（localhost:5000/hello）时，出现404错误。此请求的日志中显示以下信息（here是一个要点，因为我不喜欢将其格式化为引用的方式）：

  

2018-02-05 13：01：37.600 DEBUG 17448 --- [nio-5000-exec-2]   o.a.coyote.http11.Http11InputBuffer：收到[GET / HTTP / 1.1
  cache-control：no-cache User-Agent：PostmanRuntime / 7.1.1接受：    / 主机：127.0.0.1:5000 accept-encoding：gzip，deflate Connection：keep-alive] 2018-02-05 13：01：37.601 DEBUG 17448   --- [nio-5000-exec-2] o.a.c.authenticator.AuthenticatorBase：安全检查请求GET / 2018-02-05 13：01：37.601 DEBUG 17448   --- [nio-5000-exec-2] org.apache.catalina.realm.RealmBase：没有定义适用的约束2018-02-05 13：01：37.601 DEBUG 17448   --- [nio-5000-exec-2] o.a.c.authenticator.AuthenticatorBase：不受任何约束2018-02-05 13：01：37.604 DEBUG 17448 ---   [nio-5000-exec-2] o.a.tomcat.util.net.SocketWrapperBase：套接字：   [org.apache.tomcat.util.net.NioEndpoint$NioSocketWrapper@4bfc0a6：org.apache.tomcat.util.net.NioChannel@b945368：java.nio.channels.SocketChannel中[连接   local = / 127.0.0.1：5000 remote = / 127.0.0.1:53684]]，从缓冲区读取：[0]   2018-02-05 13：01：37.604 DEBUG 17448 --- [nio-5000-exec-2]   o.apache.coyote.http11.Http11Processor：套接字：   [org.apache.tomcat.util.net.NioEndpoint$NioSocketWrapper@4bfc0a6：org.apache.tomcat.util.net.NioChannel@b945368：java.nio.channels.SocketChannel中[连接   local = / 127.0.0.1：5000 remote = / 127.0.0.1：53684]]，状态：   [OPEN_READ]，声明：[OPEN]

我确定我错过了一些非常基本的东西，但我不能为我的生活找出什么。在此先感谢：）

Answer 1

您提供的信息还不够。

当我使用这个pom.xml尝试你的应用程序和控制器时：

<?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.example</groupId>
    <artifactId>mvc</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>MVC</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <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-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

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

</project>

它适用于server.contextPath=/以及注释时。

Answer 2

此代码适用于我，除了以下代码之外没有单个字符可以运行spring boot simple API。我认为您的应用程序中存在一些配置类或pom问题。

<强>的pom.xml

<?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.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.10.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <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-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

<强> HelloController.java

package com.example.demo;

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

@RestController
public class HelloController {

    @RequestMapping("/hello")
    public String sayHello() {
        return "Hello, world!";
    }
}

<强> DemoApplication.java

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

<强> application.properties

server.port = 5000
logging.level.org=DEBUG

成功运行