Question

我正在使用spring boot构建spring mvc项目，但我无法启动我的Web应用程序。我已经关注了几个教程，但无法弄明白。我可以用spring boot启动我的应用程序但是当我添加Spring mvc时，它开始抛出错误。我收到了以下错误

java.lang.NullPointerException：null 在org.springframework.core.BridgeMethodResolver.findBridgedMethod（BridgeMethodResolver.java:60）在org.springframework.beans.GenericTypeAwarePropertyDescriptor。（GenericTypeAwarePropertyDescriptor.java:70） at org.springframework.beans.CachedIntrospectionResults.buildGenericTypeAwarePropertyDescriptor（CachedIntrospectionResults.java:366）在org.springframework.beans.CachedIntrospectionResults。（CachedIntrospectionResults.java:302）在org.springframework.beans.CachedIntrospectionResults.forClass（CachedIntrospectionResults.java:189）在org.springframework.beans.BeanUtils.getPropertyDescriptors（BeanUtils.java:354）在org.springframework.boot.bind.PropertiesConfigurationFactory.getNames（PropertiesConfigurationFactory.java:288）在org.springframework.boot.bind.PropertiesConfigurationFactory.doBindPropertiesToTarget（PropertiesConfigurationFactory.java:269）在org.springframework.boot.bind.PropertiesConfigurationFactory.bindPropertiesToTarget（PropertiesConfigurationFactory.java:240）在org.springframework.boot.context.config.ConfigFileApplicationListener.bindToSpringApplication（ConfigFileApplicationListener.java:241）在org.springframework.boot.context.config.ConfigFileApplicationListener.postProcessEnvironment（ConfigFileApplicationListener.java:197） at org.springframework.boot.context.config.ConfigFileApplicationListener.onApplicationEnvironmentPreparedEvent（ConfigFileApplicationListener.java:182）在org.springframework.boot.context.config.ConfigFileApplicationListener.onApplicationEvent（ConfigFileApplicationListener.java:168）在org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener（SimpleApplicationEventMulticaster.java:172）在org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener（SimpleApplicationEventMulticaster.java:165）在org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent（SimpleApplicationEventMulticaster.java:139）在org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent（SimpleApplicationEventMulticaster.java:127）在org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared（EventPublishingRunListener.java:74）在org.springframework.boot.SpringApplicationRunListeners.environmentPrepared（SpringApplicationRunListeners.java:54）在org.springframework.boot.SpringApplication.prepareEnvironment（SpringApplication.java:325）在org.springframework.boot.SpringApplication.run（SpringApplication.java:296）在org.springframework.boot.SpringApplication.run（SpringApplication.java:1118）在org.springframework.boot.SpringApplication.run（SpringApplication.java:1107）在com.azzimov.search.BootStarter.StartApplication.main（StartApplication.java:17） at sun.reflect.NativeMethodAccessorImpl.invoke0（Native Method） at sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:62） at sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43） at java.lang.reflect.Method.invoke（Method.java:498）在org.springframework.boot.maven.AbstractRunMojo $ LaunchRunner.run（AbstractRunMojo.java:527）在java.lang.Thread.run（Thread.java:745）[警告] java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0（Native Method） at sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:62） at sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43） at java.lang.reflect.Method.invoke（Method.java:498）在org.springframework.boot.maven.AbstractRunMojo $ LaunchRunner.run（AbstractRunMojo.java:527） at java.lang.Thread.run（Thread.java:745）引起：java.lang.NullPointerException 在org.springframework.core.BridgeMethodResolver.findBridgedMethod（BridgeMethodResolver.java:60）在org.springframework.beans.GenericTypeAwarePropertyDescriptor。（GenericTypeAwarePropertyDescriptor.java:70） at org.springframework.beans.CachedIntrospectionResults.buildGenericTypeAwarePropertyDescriptor（CachedIntrospectionResults.java:366）在org.springframework.beans.CachedIntrospectionResults。（CachedIntrospectionResults.java:302）在org.springframework.beans.CachedIntrospectionResults.forClass（CachedIntrospectionResults.java:189）在org.springframework.beans.BeanUtils.getPropertyDescriptors（BeanUtils.java:354）在org.springframework.boot.bind.PropertiesConfigurationFactory.getNames（PropertiesConfigurationFactory.java:288）在org.springframework.boot.bind.PropertiesConfigurationFactory.doBindPropertiesToTarget（PropertiesConfigurationFactory.java:269）在org.springframework.boot.bind.PropertiesConfigurationFactory.bindPropertiesToTarget（PropertiesConfigurationFactory.java:240）在org.springframework.boot.context.config.ConfigFileApplicationListener.bindToSpringApplication（ConfigFileApplicationListener.java:241）在org.springframework.boot.context.config.ConfigFileApplicationListener.postProcessEnvironment（ConfigFileApplicationListener.java:197） at org.springframework.boot.context.config.ConfigFileApplicationListener.onApplicationEnvironmentPreparedEvent（ConfigFileApplicationListener.java:182）在org.springframework.boot.context.config.ConfigFileApplicationListener.onApplicationEvent（ConfigFileApplicationListener.java:168）在org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener（SimpleApplicationEventMulticaster.java:172）在org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener（SimpleApplicationEventMulticaster.java:165）在org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent（SimpleApplicationEventMulticaster.java:139）在org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent（SimpleApplicationEventMulticaster.java:127）在org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared（EventPublishingRunListener.java:74）在org.springframework.boot.SpringApplicationRunListeners.environmentPrepared（SpringApplicationRunListeners.java:54）在org.springframework.boot.SpringApplication.prepareEnvironment（SpringApplication.java:325）在org.springframework.boot.SpringApplication.run（SpringApplication.java:296）在org.springframework.boot.SpringApplication.run（SpringApplication.java:1118）在org.springframework.boot.SpringApplication.run（SpringApplication.java:1107）在com.azzimov.search.BootStarter.StartApplication.main（StartApplication.java:17） ......还有6个

我的pom.xml是

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.8.RELEASE</version>
  </parent>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>4.0.0</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.0.1.RELEASE</version>
    </dependency>


    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.0.1.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>5.0.1.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
      <version>1.5.8.RELEASE</version>
    </dependency>

  </dependencies>
  <build>
    <finalName>azzimov-search</finalName>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.7.0</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>

      <plugin>
        <groupId>org.apache.tomcat.maven</groupId>
        <artifactId>tomcat7-maven-plugin</artifactId>
        <version>2.2</version>
      </plugin>

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

    </plugins>

    <resources>
      <resource>
        <directory>src/clients</directory>
      </resource>
    </resources>
  </build>

我的web.xml是

<webapp>
<servlet>
    <servlet-name>dispatcher</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>/WEB-INF/web-config.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>dispatcher</servlet-name>
    <url-pattern>/gw/*</url-pattern>
  </servlet-mapping>
</web-app>

我的web-config.xml是

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/mvc
                           http://www.springframework.org/schema/mvc/spring-mvc.xsd
                           http://www.springframework.org/schema/context
                           http://www.springframework.org/schema/context/spring-context.xsd ">

    <mvc:annotation-driven />
    <context:component-scan base-package="com.project.book" />
</beans>

Answer 1

从例外情况来看，它显然是一个依赖问题。您可以尝试使用最新版本的spring-boot而不是1.5.8.RELEASE吗？

Answer 2

您正在尝试将Spring Boot 1.5与Spring 5混合使用。由于它们不兼容，因此不会以这种方式工作。如果你真的需要Spring Framework 5，你应该使用Spring Boot 2.x启动程序父。

根据您的需要，您可以使用下面的pom.xml并将1.5.8.RELEASE更改为2.0.0.M5，或保持不变。

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.8.RELEASE</version>
</parent>

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
</dependencies>
<build>
    <finalName>azzimov-search</finalName>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
            </configuration>
        </plugin>

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

    </plugins>

    <resources>
        <resource>
            <directory>src/clients</directory>
        </resource>
    </resources>
</build>

请注意，我从依赖项中删除了版本，因此它们来自父启动器。

另外，请删除web.xml和web-config.xml，因为Spring Boot不需要它们。而是在根包中创建一个类（可能是com.project或com.project.book）：

@SpringBootApplication
public class BookApp {

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

Answer 3

不明确指定spring mvc或核心版本，它将自动采用1.5.8.RELEASE spring boot的兼容版本。

使用Spring MVC运行Sprint Boot时抛出Nullpointer异常

3 个答案: