小编use*_*601的帖子

我试图了解如何在本机代码中处理套接字读取超时,并发现一些奇怪的硬编码值,即5000毫秒:

if (timeout) {
    if (timeout <= 5000 || !isRcvTimeoutSupported) {
        int ret = NET_Timeout (fd, timeout);
        .....
        .....
    }
}

来源:http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/687fd7c7986d/src/windows/native/java/net/SocketInputStream.c

我可以看到,变量isRcvTimeoutSupported通常设置为true,但在设置套接字选项时可能会被删除为false:

    /*
     * SO_RCVTIMEO is only supported on Microsoft's implementation
     * of Windows Sockets so if WSAENOPROTOOPT returned then
     * reset flag and timeout will be implemented using
     * select() -- see SocketInputStream.socketRead.
     */

    if (isRcvTimeoutSupported) {
        jclass iCls = (*env)->FindClass(env, "java/lang/Integer");
        jfieldID i_valueID;
        jint timeout;

        CHECK_NULL(iCls);
        i_valueID = (*env)->GetFieldID(env, iCls, "value", "I");
        CHECK_NULL(i_valueID);
        timeout …

我需要从jar加载XSD文件,所以实现了LSResourceResolver,如下所示:

        Source schemaFile = new StreamSource(getClass().getClassLoader().getResourceAsStream("resources/xsd/root/maindoc/MainSchema.xsd"));
        SchemaFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
        schemaFactory.setResourceResolver(new LSResourceResolver(){
            @Override
            public LSInput resolveResource(String type, String namespaceURI, String publicId, String systemId, String baseURI) {
                    LSInput input = new DOMInputImpl();
                String filePath = getNormalizedPath("resources/xsd/root/maindoc/", systemId);
                InputStream stream = getClass().getClassLoader().getResourceAsStream(filePath);
                input.setPublicId(publicId);
                input.setSystemId(systemId);
                input.setBaseURI(baseURI);
                input.setCharacterStream(new InputStreamReader(stream));             
                return input;
            }

        });         
        Schema schema = schemaFactory.newSchema(schemaFile); 

此类实现成功解析了主模式中的链接,但无法解析引用文档中的链接.

通过引用文档的调用,我收到的不是null的baseURI参数,但是在我的情况下它的值就像是"file:///var/xxx/yyy.xsd",所以看起来不可能从这个构造一个有效的路径的systenId.

我错过了什么吗？是否可以递归地使解析器工作？

当然有一种解决方法可以展平架构,但我不太喜欢它.

注意到生产服务器(Websphere8.5.5)开始消耗大量内存.

javacore转储中的数字清楚地表明罪魁祸首是一堆杂乱无章的堆:

|  +--Memory Manager (GC): 5,496,900,272 bytes / 3193 allocations
|  |  |
|  |  +--Java Heap: 5,368,770,560 bytes / 1 allocation
|  |  |
|  |  +--Other: 128,129,712 bytes / 3192 allocations  

但与此同时,在MAT中打开的堆转储报告堆的总容量大约为200M(有时高达300M,但从不多).

它到底意味着什么？堆转储是否值得信赖？如果是,是否有办法释放未使用的堆内存？

更新:完整的NATIVEMEM部分,根据要求

1MEMUSER       JRE: 7,211,791,256 bytes / 39196 allocations
1MEMUSER       |
2MEMUSER       +--VM: 6,772,051,048 bytes / 29934 allocations
2MEMUSER       |  |
3MEMUSER       |  +--Classes: 370,339,176 bytes / 10002 allocations
3MEMUSER       |  |  |
4MEMUSER       |  |  +--Shared Class Cache: 62,914,560 bytes / 1 allocation
3MEMUSER …