我收到此错误 "Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException"

Question

我在添加 swagger 配置时不断收到此错误 ui 确实有帮助，因为我卡在了这一点上。我已经尝试添加 ant-path-matcher 策略，但它不起作用

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2022-05-24 11:07:48.532 ERROR 1624 --- [  restartedMain] o.s.boot.SpringApplication               : Application run failed

org.springframework.context.ApplicationContextException: Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException
    at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:181) ~[spring-context-5.3.20.jar:5.3.20]
    at org.springframework.context.support.DefaultLifecycleProcessor.access0(DefaultLifecycleProcessor.java:54) ~[spring-context-5.3.20.jar:5.3.20]
    at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:356) ~[spring-context-5.3.20.jar:5.3.20]
    at java.lang.Iterable.forEach(Iterable.java:75) ~[na:1.8.0_333]
    at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:155) ~[spring-context-5.3.20.jar:5.3.20]
    at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:123) ~[spring-context-5.3.20.jar:5.3.20]
    at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:935) ~[spring-context-5.3.20.jar:5.3.20]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:586) ~[spring-context-5.3.20.jar:5.3.20]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.6.8.jar:2.6.8]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:745) [spring-boot-2.6.8.jar:2.6.8]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:420) [spring-boot-2.6.8.jar:2.6.8]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-2.6.8.jar:2.6.8]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1317) [spring-boot-2.6.8.jar:2.6.8]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1306) [spring-boot-2.6.8.jar:2.6.8]
    at com.wipro.gl.Library1Application.main(Library1Application.java:11) [classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_333]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_333]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_333]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_333]
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-2.6.8.jar:2.6.8]
Caused by: java.lang.NullPointerException: null
    at springfox.documentation.spi.service.contexts.Orderings.compare(Orderings.java:112) ~[springfox-spi-2.9.2.jar:null]
    at springfox.documentation.spi.service.contexts.Orderings.compare(Orderings.java:109) ~[springfox-spi-2.9.2.jar:null]
    at com.google.common.collect.ComparatorOrdering.compare(ComparatorOrdering.java:37) ~[guava-20.0.jar:na]
    at java.util.TimSort.countRunAndMakeAscending(TimSort.java:355) ~[na:1.8.0_333]
    at java.util.TimSort.sort(TimSort.java:220) ~[na:1.8.0_333]
    at java.util.Arrays.sort(Arrays.java:1438) ~[na:1.8.0_333]
    at com.google.common.collect.Ordering.sortedCopy(Ordering.java:855) ~[guava-20.0.jar:na]
    at springfox.documentation.spring.web.plugins.WebMvcRequestHandlerProvider.requestHandlers(WebMvcRequestHandlerProvider.java:57) ~[springfox-spring-web-2.9.2.jar:null]
    at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.apply(DocumentationPluginsBootstrapper.java:138) ~[springfox-spring-web-2.9.2.jar:null]
    at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.apply(DocumentationPluginsBootstrapper.java:135) ~[springfox-spring-web-2.9.2.jar:null]
    at com.google.common.collect.Iterators.transform(Iterators.java:750) ~[guava-20.0.jar:na]
    at com.google.common.collect.TransformedIterator.next(TransformedIterator.java:47) ~[guava-20.0.jar:na]
    at com.google.common.collect.TransformedIterator.next(TransformedIterator.java:47) ~[guava-20.0.jar:na]
    at com.google.common.collect.MultitransformedIterator.hasNext(MultitransformedIterator.java:52) ~[guava-20.0.jar:na]
    at com.google.common.collect.MultitransformedIterator.hasNext(MultitransformedIterator.java:50) ~[guava-20.0.jar:na]
    at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:249) ~[guava-20.0.jar:na]
    at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:209) ~[guava-20.0.jar:na]
    at com.google.common.collect.FluentIterable.toList(FluentIterable.java:614) ~[guava-20.0.jar:na]
    at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.defaultContextBuilder(DocumentationPluginsBootstrapper.java:111) ~[springfox-spring-web-2.9.2.jar:null]
    at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.buildContext(DocumentationPluginsBootstrapper.java:96) ~[springfox-spring-web-2.9.2.jar:null]
    at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.start(DocumentationPluginsBootstrapper.java:167) ~[springfox-spring-web-2.9.2.jar:null]
    at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:178) ~[spring-context-5.3.20.jar:5.3.20]
    ... 19 common frames omitted

这是我的 pom 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>2.6.8</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.wipro.gl</groupId>
    <artifactId>Library1</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>Library1</name>
    <description> Project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
            <version>2.9.2</version>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>2.9.2</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

        </plugins>
    </build>

</project>

这是我的配置文件

@Configuration
@EnableSwagger2
public class springConfig {

    @Bean
    public Docket library() {
        return new Docket(DocumentationType.SWAGGER_2).groupName("Library").select()
                .apis(RequestHandlerSelectors.basePackage("com.wipro.gl.controller")).build();
    }

}

Answer 1

看起来最新的 spring-boot 版本 2.6.8 与 Swagger 2 不兼容。我遇到了同样的问题，有两种解决方法。

尝试将您的 springboot 版本降级到低于 2.5.8（简单的解决方法）。
将swagger升级为OpenApi，很可能被称为Swagger3。这与注释几乎没有变化。您可以按照 Internet 上提供的指南轻松地从 Swagger 2 迁移到 OpenApi 3。

升级swagger的第二种解决方法更可取，因为springfox的Swagger 2变老了，最后一个版本发布于2020年7月。OpenApi是最新的api规范。

我收到此错误 "Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException"

I am getting this error "Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException"

java

spring

spring-boot