【发布时间】：2023-03-22 09:33:01
【问题描述】：
我一直在学习以下教程：
http://spring.io/guides/gs/rest-service/
我最初能够让代码正常工作（运行完成的教程，发送 HTTP 消息并获得正确的响应）并成功扩展它。
进一步扩展后，我遇到了以下异常：
java.lang.IllegalStateException: Could not evaluate condition on org.springframework.boot.autoconfigure.PropertyPlaceholderAutoConfiguration#propertySourcesPlaceholderConfigurer due to internal class not found. This can happen if you are @ComponentScanning a springframework package (e.g. if you put a @ComponentScan in the default package by mistake)
at org.springframework.boot.autoconfigure.condition.SpringBootCondition.matches(SpringBootCondition.java:51)
at org.springframework.context.annotation.ConditionEvaluator.shouldSkip(ConditionEvaluator.java:92)
at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForBeanMethod(ConfigurationClassBeanDefinitionReader.java:174)
at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForConfigurationClass(ConfigurationClassBeanDefinitionReader.java:136)
at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitions(ConfigurationClassBeanDefinitionReader.java:116)
at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:330)
at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:243)
at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:254)
at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:94)
at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:611)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:464)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:109)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:691)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:321)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:961)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:950)
at com.aharrison.hello.Application.main(Application.java:15)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)
我已将代码剥离回仅显示示例中的内容，但我仍然遇到异常。
我认为它可能与以下问题有关，尽管它被标记为已关闭：
https://github.com/spring-projects/spring-boot/issues/2050
我对 Spring 不是很有经验，所以我无法完全理解所讨论的内容。
这是我目前的课程：
Greeting.java：
package com.aharrison.hello;
public class Greeting {
private final long id;
private final String content;
public Greeting(long id, String content) {
this.id = id;
this.content = content;
}
public long getId() {
return id;
}
public String getContent() {
return content;
}
}
问候控制器：
package com.aharrison.hello;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import java.util.concurrent.atomic.AtomicLong;
@RestController
public class GreetingController {
private static final String template = "Hello, %s!";
private final AtomicLong counter = new AtomicLong();
@RequestMapping("/greeting")
public Greeting greeting(@RequestParam(value="name", defaultValue="World") String name) {
return new Greeting(counter.incrementAndGet(), String.format(template, name));
}
}
Application.java：
package com.aharrison.hello;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
/**
* Created by Adam on 12/26/2014.
*/
@ComponentScan
@EnableAutoConfiguration
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
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.aharrison</groupId>
<artifactId>SpringRestAPI</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>1.2.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.1.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-mongodb</artifactId>
<version>1.6.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.mongodb</groupId>
<artifactId>mongo-java-driver</artifactId>
<version>2.12.2</version>
</dependency>
</dependencies>
问题：
- 在这种情况下是什么导致了异常？我上面的代码有问题，还是问题环境相关？
- 当异常显示“..如果您错误地将@ComponentScan 放入默认包中”时，它指的是哪个默认包？这适用于目前的情况吗？
提前致谢。
【问题讨论】：
-
check this link这个文档对如何使用maven配置spring boot应用有清晰的解释。
-
显然这个问题不断获得流量。老实说，我多年来一直没有研究导致这个问题的任何原因。我从未接受过答案，因为我没有找到解决方案；让我知道这是否是不好的形式。祝大家好运。
标签： java spring rest maven spring-mvc