java - 启动后 Spring Boot 应用程序失败 - 尝试调用不存在的方法。尝试是从以下位置进行的

Question

我是 Spring Boot 的新手，我正在尝试使用 REST Api 构建一个简单的应用程序，但在启动应用程序时我立即收到此错误:

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2021-01-24 20:08:19.505 ERROR 11344 --- [  restartedMain] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

An attempt was made to call a method that does not exist. The attempt was made from the following location:

    org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration$EnableWebMvcConfiguration.requestMappingHandlerAdapter(WebMvcAutoConfiguration.java:369)

The following method did not exist:

    'org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration.requestMappingHandlerAdapter(org.springframework.web.accept.ContentNegotiationManager, org.springframework.format.support.FormattingConversionService, org.springframework.validation.Validator)'

The method's class, org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration, is available from the following locations:

    jar:file:/C:/Users/user/.m2/repository/org/springframework/spring-webmvc/5.1.3.RELEASE/spring-webmvc-5.1.3.RELEASE.jar!/org/springframework/web/servlet/config/annotation/DelegatingWebMvcConfiguration.class

The class hierarchy was loaded from the following locations:

    org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration: file:/C:/Users/user/.m2/repository/org/springframework/spring-webmvc/5.1.3.RELEASE/spring-webmvc-5.1.3.RELEASE.jar
    org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport: file:/C:/Users/user/.m2/repository/org/springframework/spring-webmvc/5.1.3.RELEASE/spring-webmvc-5.1.3.RELEASE.jar


Action:

Correct the classpath of your application so that it contains a single, compatible version of org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration


Process finished with exit code 0

我还没有完成应用程序的开发，但由于这个错误我无法继续。

到目前为止我的类(class)是:

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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.2</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>micro1</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>micro1</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>11</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>



        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>javax.persistence</groupId>
            <artifactId>javax.persistence-api</artifactId>
            <version>2.2</version>
        </dependency>
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
<!--            <version>1.4.200</version>-->
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.1.3.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
    </dependencies>


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




            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>2.19.1</version>
            </plugin>
        </plugins>
    </build>

</project>

Controller :

package com.example.micro1.controllers;

import com.example.micro1.entities.User;
import com.example.micro1.services.Service;
import lombok.Data;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/users")
@Data
public class Controller {
    private final Service service;

    @PostMapping
    User addNewUser(@RequestBody User user){
        return service.add(user);
    }
}

服务:

package com.example.micro1.services;


import com.example.micro1.entities.User;
import com.example.micro1.repositories.Repository;
import lombok.Data;

@org.springframework.stereotype.Service
@Data
public class Service {
    private final Repository repository;

    public User add(User user){
        return repository.save(user);
    }
}

存储库:

package com.example.micro1.repositories;

import com.example.micro1.entities.User;
import org.springframework.data.jpa.repository.JpaRepository;

@org.springframework.stereotype.Repository
public interface Repository extends JpaRepository<User, Integer> {
    @Override
    <S extends User> S save(S s);
}

现在一个实体:

package com.example.micro1.entities;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int id;
    private String name;
    private String phoneNumber;
}

应用程序属性:

#h2
spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=password
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
spring.h2.console.enabled=true

应用类:

package com.example.micro1;

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

@SpringBootApplication
public class Micro1Application {

    public static void main(String[] args) {
        SpringApplication.run(Micro1Application.class, args);
    }

}

请告诉我是否还有什么我应该写在这里...谢谢!

Answer 1

你的启动器 spring-boot-starter-web 本身包含这些依赖项

<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-web</artifactId>
  <version>5.3.3</version>
  <scope>compile</scope>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-webmvc</artifactId>
  <version>5.3.3</version>
  <scope>compile</scope>
</dependency>

此外，您在 pom.xml 中添加:

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.1.3.RELEASE</version>
    </dependency>

因此，当您启动您的应用程序时，您会遇到类路径歧义。我认为这是你的问题的原因。Spring Boot 启动器为您省去指定显式声明依赖项的麻烦。尝试移除 spring-webmvc 依赖。