WebSphere 8内存泄漏

Question

我有一个应用程序部署到Eclipse8.5(应用程序是使用java8 8/Spring4开发的)，每天我都会得到许多转储文件，所以我决定使用WebSphere内存分析器来分析它，结果是：

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问题是我不使用axis来调用web服务，只对Rest服务使用Jersy，对于soap服务使用默认的jdk类SoapConnection，下面是一些代码示例:对于Soap：

public String soapBind(List<ContextItem> dic, String serviceId, String urlWs, String applicationId) throws SOAPException, Exception {
    try {
        SOAPConnectionFactory soapConnectionFactory = SOAPConnectionFactory.newInstance();
        SOAPConnection soapConnection = soapConnectionFactory.createConnection();
        SOAPMessage msg = soapCall(dic, serviceId, applicationId); // Send SOAP Message to SOAP Server

        String url = urlWs;
        LOGGER.info("CALLING WS ....");
        SOAPMessage soapResponse = soapConnection.call(msg, url);

        // print SOAP Response
       
        //soapResponse.writeTo(System.out);
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        soapResponse.writeTo(out);
        soapConnection.close();

        String strMsg = new String(out.toByteArray());
        LOGGER.info("Response SOAP Message: {}",strMsg);
        return strMsg;

    } catch (SOAPException ex) {
        throw ex;
    } catch (UnsupportedOperationException ex) {
        throw ex;
    } catch (Exception ex) {
        throw ex;
    }
}

休息：

Client client = Client.create();
 WebResource webResource = client
 .resource(urlFicheClientProf);
//
 ServiceContext serviceContext = this.getServiceContext();
//
ObjectMapper mapper = new ObjectMapper();

 ClientResponse response = webResource
 .queryParam("customerId", radical)
 .queryParam("serviceContext",
 URLEncoder.encode(mapper.writeValueAsString(serviceContext),
 "UTF-8"))
 .post(ClientResponse.class);

我想知道为什么内存中出现了Axis.Client，以及如何修复它。如果有人能帮我弄清楚，我会非常感激的。

Answer 1

使用RestTemplate而不是SOAPConnection修复内存泄漏：

   final RestTemplate restTemplate = new RestTemplate();
            final HttpHeaders headers = new HttpHeaders();
            headers.add("Content-Type", "text/xml");
            final HttpEntity<String> request = new HttpEntity<>(message, headers);
            final String result = restTemplate.postForObject(wsUrl, request, String.class);
            return result;

Answer 2

关于第一个问题:为什么使用默认的JDK类Axis2时使用Apache？类SOAPConnection实际上只是API的一部分，可以有不同的实现。在您的例子中，WebSphere基于Apache提供了这个API的实现，这就是为什么您看到这些类的对象挥之不去的原因。SOAPConnection Javadocs状态：

SOAPConnection类是可选的。有些实现可能不实现这个接口，在这种情况下，对SOAPConnectionFactory.newInstance()的调用(参见下面)将抛出一个UnsupportedOperationException。

关于你问题的第二部分，我有一个假设。在Javadocs中，我无法找到对SOAPConnection.close()的调用是否是强制性的，但是通常带有close()方法的资源类确实需要清理，否则它们会创建内存或其他资源泄漏。您的代码确实调用了close()，但是如果在关闭连接之前某个地方发生异常，则执行将直接跳转到catch (.)并且连接将不会被清除，从而造成内存泄漏。也许每次SOAP调用抛出异常时都会发生这种情况，并且泄漏了您正在观察的内存。

您可以通过使用这里描述的尝试-资源关闭模式来解决这个问题：https://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html在代码中尝试以下更改。

编辑

public String soapBind(List<ContextItem> dic, String serviceId, String urlWs, String applicationId) throws SOAPException, Exception {
    try {
        SOAPConnectionFactory soapConnectionFactory = SOAPConnectionFactory.newInstance();
        try (MySOAPConnection mySoapConnection = new MySOAPConnection(soapConnectionFactory)) {
            SOAPConnection soapConnection = mySoapConnection.connection;
            SOAPMessage msg = soapCall(dic, serviceId, applicationId); // Send SOAP Message to SOAP Server

            String url = urlWs;
            LOGGER.info("CALLING WS ....");
            SOAPMessage soapResponse = soapConnection.call(msg, url);

            // print SOAP Response
           
            //soapResponse.writeTo(System.out);
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            soapResponse.writeTo(out);
            
            String strMsg = new String(out.toByteArray());
            LOGGER.info("Response SOAP Message: {}",strMsg);
            return strMsg;
        }
    } catch (SOAPException ex) {
        throw ex;
    } catch (UnsupportedOperationException ex) {
        throw ex;
    } catch (Exception ex) {
        throw ex;
    }
}

public class MySOAPConnection implements AutoCloseable {

    public final SOAPConnection connection;
    
    public MySOAPConnection(SOAPConnectionFactory soapConnectionFactory)
    {
        this.connection = soapConnectionFactory.createConnection();
    }
    
    @Override
    public void close() throws Exception {
        this.connection.close();            
    }
}

请注意，当您使用try-resource时，不应该显式地调用close()方法，否则您将得到双close()！