Spring Boot 类定义未找到错误答案

【问题标题】：Spring Boot class def not found errorSpring Boot 类定义未找到错误
【发布时间】：2017-05-16 17:38:02
【问题描述】：

我有一个简单的 Spring Boot 应用程序，用于连接到 REST api 并查看它的响应。这是一个简单的原型设计应用程序。但是我收到以下错误：

Exception in thread "main" java.lang.NoClassDefFoundError: [Lcom/crossover/techtrial/java/se/dto/Account;
    at com.crossover.techtrial.java.se.TrialApplication.main(TrialApplication.java:25)
Caused by: java.lang.ClassNotFoundException: com.crossover.techtrial.java.se.dto.Account
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    ... 1 more

我不知道为什么会这样，因为我已经定义了 Account 类：

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

@JsonIgnoreProperties(ignoreUnknown = true)
public class Account 
{
    private String id;

    private MonetaryAmount monetaryAmount;

    public Account()
    {

    }

    public String getId() 
    {
        return id;
    }

    public void setId(String id) 
    {
        this.id = id;
    }

    public  MonetaryAmount getMonetaryAmount() 
    {
        return monetaryAmount;
    }

    public void setMonetaryAmount(MonetaryAmount monetaryAmount) 
    {
        this.monetaryAmount = monetaryAmount;
    }

}

我的调用代码：

package com.crossover.techtrial.java.se;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.client.RestTemplate;

import com.crossover.techtrial.java.se.dto.Account;

@SpringBootApplication
public class TrialApplication 
{
    @Autowired
    public static RestTemplate restTemplate;

    @Value("${apiforest.baseuri}")
    public static String baseURI;

    public static void main(String[] args) 
    {

        String url = baseURI + "/paypallets/accounts";
        //SpringApplication.run(TrialApplication.class, args);
        restTemplate.getForObject(url, Account[].class);
        System.out.println(url);
    }
}

另一个问题是它没有获取我在 application.properties 中定义的键“apiforest.baseuri”的值。

我的 application.properties：

spring.jpa.hibernate.ddl-auto=create
spring.datasource.url=jdbc:mysql://localhost:3306/SampleDB
spring.datasource.username=root
spring.datasource.password=admin
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect
management.port = 9001
apiforest.baseuri = https://api-forest/....
read.timeout = 10000
connect.timeout = 10000

我的 RestConfig：

package com.crossover.techtrial.java.se.config;


import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;

// To set the configuration parameters like read timeout and connect timeout for Rest Client
@Configuration
public class RestConfig 
{
    @Bean
    public RestTemplate createRestTemplate(final ClientHttpRequestFactory clientHttpRequestFactory)
    {
        return new RestTemplate(clientHttpRequestFactory);
    }

    @Bean
    public ClientHttpRequestFactory createClientHttpRequestFactory(@Value("${connect.timeout}") final int connectTimeout,
            @Value("${read.timeout}") final int readTimeout)
    {
        HttpComponentsClientHttpRequestFactory factory = new HttpComponentsClientHttpRequestFactory();
        factory.setConnectTimeout(connectTimeout);
        factory.setReadTimeout(readTimeout);
        return factory;
    }
}

我的 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.crossover.techtrial.java.se</groupId>
    <artifactId>trial</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

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

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.3.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>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

    </dependencies>

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


</project>

有什么想法吗？

编辑：我通过这样做将调用代码更改为@Luke 建议的内容：

@SpringBootApplication
public class TrialApplication 
{
    @Value("${apiforest.baseuri}")
    public static String baseURI;

    public static void main(String[] args) 
    {
        ConfigurableApplicationContext run = 
          SpringApplication.run(TrialApplication.class, args);
        RestTemplate restTemplate = run.getBean(RestTemplate.class);
        String url = baseURI + "/paypallets/accounts";
        restTemplate.getForObject(url, Account[].class);
        System.out.println(url);
    }
}

但是现在我得到了以下异常，其中一个仍然是 ClassdefNot Found：

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'createRestTemplate' defined in class path resource [com/crossover/techtrial/java/se/config/RestConfig.class]: Unsatisfied dependency expressed through method 'createRestTemplate' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'createClientHttpRequestFactory' defined in class path resource [com/crossover/techtrial/java/se/config/RestConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.http.client.ClientHttpRequestFactory]: Factory method 'createClientHttpRequestFactory' threw exception; nested exception is java.lang.NoClassDefFoundError: org/apache/http/client/HttpClient
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:749) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:467) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1134) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1028) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:759) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:866) ~[spring-context-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542) ~[spring-context-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:761) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:371) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1186) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1175) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at com.crossover.techtrial.java.se.TrialApplication.main(TrialApplication.java:21) [classes/:na]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'createClientHttpRequestFactory' defined in class path resource [com/crossover/techtrial/java/se/config/RestConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.http.client.ClientHttpRequestFactory]: Factory method 'createClientHttpRequestFactory' threw exception; nested exception is java.lang.NoClassDefFoundError: org/apache/http/client/HttpClient
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:599) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1134) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1028) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:207) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1136) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1064) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:835) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    ... 19 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.http.client.ClientHttpRequestFactory]: Factory method 'createClientHttpRequestFactory' threw exception; nested exception is java.lang.NoClassDefFoundError: org/apache/http/client/HttpClient
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:189) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:588) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    ... 32 common frames omitted
Caused by: java.lang.NoClassDefFoundError: org/apache/http/client/HttpClient
    at com.crossover.techtrial.java.se.config.RestConfig.createClientHttpRequestFactory(RestConfig.java:25) ~[classes/:na]
    at com.crossover.techtrial.java.se.config.RestConfig$$EnhancerBySpringCGLIB$$25eeb443.CGLIB$createClientHttpRequestFactory$1(<generated>) ~[classes/:na]
    at com.crossover.techtrial.java.se.config.RestConfig$$EnhancerBySpringCGLIB$$25eeb443$$FastClassBySpringCGLIB$$44b4ec10.invoke(<generated>) ~[classes/:na]
    at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228) ~[spring-core-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:356) ~[spring-context-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at com.crossover.techtrial.java.se.config.RestConfig$$EnhancerBySpringCGLIB$$25eeb443.createClientHttpRequestFactory(<generated>) ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_121]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_121]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_121]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_121]
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:162) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    ... 33 common frames omitted
Caused by: java.lang.ClassNotFoundException: org.apache.http.client.HttpClient
    at java.net.URLClassLoader.findClass(Unknown Source) ~[na:1.8.0_121]
    at java.lang.ClassLoader.loadClass(Unknown Source) ~[na:1.8.0_121]
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) ~[na:1.8.0_121]
    at java.lang.ClassLoader.loadClass(Unknown Source) ~[na:1.8.0_121]
    ... 44 common frames omitted

【问题讨论】：

一个建议首先删除所有内容并尝试仅使用主类启动一个简单的 Springboot 应用程序。您的主类（带有@SprinBootApplication'的类）不正确。
我什至尝试过，仍然得到我在编辑中定义的异常。这让我疯狂。我不知道如何解决它。我应该发布一个新问题吗？
尝试将此添加到您的 pom <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> </dependency>
谢谢，解决了！
我可以添加为答案，您可以接受。

标签： java rest maven spring-boot client

【解决方案1】：

用@SpringBootApplication 修复你的主类。并将此依赖项添加到您的 pom 中

<dependency> 
   <groupId>org.apache.httpcomponents</groupId> 
   <artifactId>httpclient</artifactId> 
</dependency>

【讨论】：

【解决方案2】：

我认为您不能在创建 Context 的同一个类中注入 bean（也许它适用于属性，因为 PropertySourcesPlaceholderConfigurer 是 BeanFactoryPostProcessor）。

你可以试试

SpringBootApplication
public class TrialApplication 
{
    @Value("${apiforest.baseuri}")
    public static String baseURI;

    public static void main(String[] args) 
    {
        ConfigurableApplicationContext run = 
          SpringApplication.run(TrialApplication.class, args);
        RestTemplate restTemplate = run.getBean(RestTemplate.class);
        String url = baseURI + "/paypallets/accounts";
        restTemplate.getForObject(url, Account[].class);
        System.out.println(url);
    }
}

但我只会将此解决方案用于测试（绝对不用于生产代码）

【讨论】：

我尝试了您的解决方案，但现在我遇到了这些异常：请参阅原始帖子进行编辑。我不知道如何在评论中提及新的错误，因为发布的长度太短了。