为什么在 Spring Security 中出现未知 [创建名称为“delegatingApplicationListener”的 bean 时出错]？重要

Question

我是 Spring Security 的新手，遇到了一个未知的异常，我自己无法弄清楚。 我想要的是：-我只是将用户详细信息作为输入并对密码字段进行编码并将其存储在Mysql数据库中。

项目结构：-

编码部分：-

package io.demo.miniapi.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import io.demo.miniapi.modal.User;
import io.demo.miniapi.repository.UserRepository;

@RestController
@RequestMapping("/miniapi")
public class MainController 
{
    @Autowired
    private UserRepository userRepository;
    @Autowired
    private BCryptPasswordEncoder passwordEncoder;
    
    @PostMapping("admin/add")
    public String addUser(@RequestBody User user)
    {   
        String pwd = user.getPassword();
        String encryptPwd = passwordEncoder.encode(pwd);
        user.setPassword(encryptPwd);
        userRepository.save(user);
        return "User added successfully...";
    }
}

以及安全配置java文件。

package io.spring.miniapi.securityrepository;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
    
    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.csrf().disable();
    }
    
    @Bean
    public BCryptPasswordEncoder encodePWD() {
        return new BCryptPasswordEncoder();
        
    }

}

当我运行程序时，我收到以下异常。

Exception in thread "task-2" 2020-07-22 12:36:18.711  INFO 5676 --- [  restartedMain] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'
org.springframework.beans.factory.BeanCreationNotAllowedException: Error creating bean with name 'delegatingApplicationListener': Singleton bean creation not allowed while singletons of this factory are in destruction (Do not request a bean from a BeanFactory in a destroy method implementation!)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:212)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:207)
    at org.springframework.context.event.AbstractApplicationEventMulticaster.retrieveApplicationListeners(AbstractApplicationEventMulticaster.java:245)
    at org.springframework.context.event.AbstractApplicationEventMulticaster.getApplicationListeners(AbstractApplicationEventMulticaster.java:197)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:134)
    at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:404)
    at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:361)
    at org.springframework.boot.autoconfigure.orm.jpa.DataSourceInitializedPublisher.publishEventIfRequired(DataSourceInitializedPublisher.java:99)
    at org.springframework.boot.autoconfigure.orm.jpa.DataSourceInitializedPublisher.access$100(DataSourceInitializedPublisher.java:50)
    at org.springframework.boot.autoconfigure.orm.jpa.DataSourceInitializedPublisher$DataSourceSchemaCreatedPublisher.lambda$postProcessEntityManagerFactory$0(DataSourceInitializedPublisher.java:200)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630)
    at java.base/java.lang.Thread.run(Thread.java:832)
2020-07-22 12:36:18.715  INFO 5676 --- [  restartedMain] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown initiated...
2020-07-22 12:36:18.752  INFO 5676 --- [  restartedMain] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown completed.
2020-07-22 12:36:18.755  INFO 5676 --- [  restartedMain] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2020-07-22 12:36:18.775  INFO 5676 --- [  restartedMain] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2020-07-22 12:36:19.020 ERROR 5676 --- [  restartedMain] o.s.b.d.LoggingFailureAnalysisReporter   : 

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

Description:

Field passwordEncoder in io.demo.miniapi.controller.MainController required a bean of type 'org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder' that could not be found.

The injection point has the following annotations:
    - @org.springframework.beans.factory.annotation.Autowired(required=true)


Action:

Consider defining a bean of type 'org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder' in your configuration. 

pom.xml 文件：-

<?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>2.3.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.my</groupId>
    <artifactId>spring-boot-miniapi</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-boot-miniapi</name>
    <description>Basic API using spring data JPA and spring security</description>

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

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-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>

我添加了安全依赖项，因此没有问题。

请帮助我准备面试的目的......

Answer 1

Spring Boot 默认会扫描带有

@SpringBootApplication

注释的类所在的完整包和子包。查看您的项目结构，您的包结构很糟糕（包

io.spring.miniapi

不在

io.demo.miniapi

内部）。通常，在具有 Maven 结构的 Java 应用程序中，您有一个名为

[domain].[companyName]

的根包（适合您的情况的 io.demo.miniapi），然后在其中创建子包。

知道这一点后，您有两个选择：

1. 创建根包

   io.demo.miniapi

   ，然后在里面创建子包。另外，将您的

   SpringBootMiniapiApplication.java

   移动到根包。
2. 在您的

   @ComponentScan

   中使用

   SpringBootMiniapiApplication.java

   。