使用Spring webServiceTemplate和jaxb库会导致«java.lang.ref.Finalizer»的内存泄漏

Question

我在我的多线程应用程序(10个线程)中执行webServiceTemplate.marshalSendAndReceive，它导致了终结器类的内存泄漏。我在调试时发现了哪些类在其实现中使用了finalize。在大多数情况下，它是UnmarshallerImpl和HttpsURLConnectionImpl。Jaxb2Marshaller为每个请求创建新的UnmarshallerImpl实例，正如我所发现的，GC不能删除这个对象，直到低优先级线程为每个实例执行finalize()。显然，FinalizerThread不能及时处理这个对象的队列，也不能释放内存。当我模拟调用webServiceTemplate.marshalSendAndReceive的方法时，内存泄漏的问题就消失了。有没有办法解决这个问题？

下面是我的WebServise配置：

@Configuration
public class WebServiceConfig {
    private final Props props;
    private final ApplicationProps applicationProps;

    public WebServiceConfig(@NotNull final Props props, @NotNull final ApplicationProps applicationProps) {
        this.props = props;
        this.applicationProps = applicationProps;
    }

    @Bean
    public Jaxb2Marshaller marshaller() {
        Jaxb2Marshaller marshaller = new Jaxb2Marshaller();
        marshaller.setPackagesToScan(applicationProps.getPackagesToScan());
        return marshaller;
    }

    @Bean
    public WebServiceTemplate webServiceTemplate(final WebServiceTemplateBuilder builder, final AllTimeouts allTimeouts) {
        return builder
                .setMarshaller(marshaller())
                .setUnmarshaller(marshaller())
                .messageSenders(new BasicAuthHttpsConnectionMessageSender(
                        props.getUsername(),
                        props.getPassword(),
                        allTimeouts.getReadTimeout()))
                .build();
    }

}


public class BasicAuthHttpsConnectionMessageSender extends HttpsUrlConnectionMessageSender {
    private final String b64Creds;

    public BasicAuthHttpsConnectionMessageSender(final String username,
                                                 final String password,
                                                 final Integer readTimeout) {
        byte[] message;
        message = String.format("%s:%s", username, password).getBytes(StandardCharsets.UTF_8);
        b64Creds = DatatypeConverter.printBase64Binary(message);
        setReadTimeout(Duration.ofMillis(readTimeout));
    }

    @Override
    protected void prepareConnection(final HttpURLConnection connection) throws IOException {
        connection.setRequestProperty(HttpHeaders.AUTHORIZATION, String.format("Basic %s", b64Creds));
        super.prepareConnection(connection);
    }
}

以下是我的依赖项：

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-jdbc'
    implementation 'org.springframework.boot:spring-boot-starter-web'
    implementation 'org.springframework.boot:spring-boot-starter-web-services'
    implementation 'org.springframework.boot:spring-boot-starter-actuator'
    implementation group: 'javax.validation', name: 'validation-api', version: '2.0.1.Final'
    implementation group: 'ch.qos.logback', name: 'logback-classic', version: '1.2.3'
    implementation group: 'net.logstash.logback', name: 'logstash-logback-encoder', version: '4.10'
    compile('javax.xml.bind:jaxb-api:2.3.0')
    compile('javax.activation:activation:1.1')
    compile('org.glassfish.jaxb:jaxb-runtime:2.3.0')
    compile 'org.hibernate.validator:hibernate-validator:6.0.13.Final'
    compile group: 'org.postgresql', name: 'postgresql', version: '42.2.11'
    compile group: 'org.springframework.vault', name: 'spring-vault-core', version: '2.1.3.RELEASE'
    compile group: 'org.springframework.ws', name: 'spring-ws-security', version: '2.2.2.RELEASE'
    compile group: 'org.springframework.ws', name: 'spring-ws-support', version: '2.2.2.RELEASE'
    compile group: 'org.springframework.boot', name: 'spring-boot-configuration-processor', version: '2.1.8.RELEASE'
    compileOnly 'org.projectlombok:lombok'
    annotationProcessor 'org.projectlombok:lombok'
    providedRuntime 'org.springframework.boot:spring-boot-starter-tomcat'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

​

​

Answer 1

虽然finalize()方法在Java9之后就被弃用了，但是如果我们使用的是jaxb，那么jaxb库仍然使用finalize.So，这样就会发生内存泄漏。你可以通过this了解更多信息。