java – 使用VTD-XML优化解析XML文件的速度

xml文件(DATEXII格式)是HD上的压缩文件.打开包装,它们大约31MB,包含超过850.000行文本.我只需要提取几个字段并将它们存储在数据库中.

import org.apache.commons.lang3.math.NumberUtils;
...

private static void test(File zipFile) throws XPathEvalException,NavException,XPathParseException {
    // init timer
    long step1=System.currentTimeMillis();

    // open file to output extracted fragments
    VTDGen vg = new VTDGen();
    vg.parseZIPFile(zipFile.getAbsolutePath(),zipFile.getName().replace(".zip",".xml"),true);

    VTDNav vn = vg.getNav();

    AutoPilot apSites = new AutoPilot();
    apSites.declareXPathNameSpace("ns1","http://schemas.xmlsoap.org/soap/envelope/");
    apSites.selectXPath("/ns1:Envelope/ns1:Body/d2LogicalModel/payloadPublication/siteMeasurements");
    apSites.bind(vn);

    long step2=System.currentTimeMillis();
    System.out.println("Prep took "+(step2-step1)+"ms; ");

    // init variables
    String siteID,timeStr;
    boolean reliable;
    int index,flow,ctr=0;
    short speed;
    while(apSites.evalXPath()!=-1) {

        vn.toElement(VTDNav.FIRST_CHILD,"measurementSiteReference");
        siteID = vn.toString(vn.getText());

        // loop all measured values of this measurement site
        while(vn.toElement(VTDNav.NEXT_SIBLING,"measuredValue")) {
            ctr++;

            // extract index attribute
            index = NumberUtils.toInt(vn.toString(vn.getAttrVal("index")));

            // go one level deeper into basicDataValue
            vn.toElement(VTDNav.FIRST_CHILD,"basicDataValue");

            // we need either FIRST_CHILD or NEXT_SIBLING depending on whether we find something
            int next = VTDNav.FIRST_CHILD;
            if(vn.toElement(next,"time")) {
                timeStr = vn.toString(vn.getText());
                next = VTDNav.NEXT_SIBLING;
            }

            if(vn.toElement(next,"averageVehicleSpeed")) {
                speed = NumberUtils.toShort(vn.toString(vn.getText()));
                next = VTDNav.NEXT_SIBLING;
            }

            if(vn.toElement(next,"vehicleFlow")) {
                flow = NumberUtils.toInt(vn.toString(vn.getText()));
                next = VTDNav.NEXT_SIBLING;
            }

            if(vn.toElement(next,"fault")) { 
                reliable = vn.toString(vn.getText()).equals("0");
            }

            // insert into database here...

            if(next==VTDNav.NEXT_SIBLING) {
                vn.toElement(VTDNav.PARENT);
            }
            vn.toElement(VTDNav.PARENT);
        }

    }
    System.out.println("Loop took "+(System.currentTimeMillis()-step2)+"ms; ");
    System.out.println("Total number of measured values: "+ctr);
}

我的XML文件的上述函数的输出是：

Prep took 25756ms; 
Loop took 26889ms; 
Total number of measured values: 112611

现在没有数据实际插入数据库.现在问题是我每分钟收到一个这样的文件.总解析时间现在接近1分钟,因为下载文件大约需要10秒钟,我需要将数据存储在数据库中,我现在正在实时运行.

有什么方法可以加快速度吗？我试过的东西没有帮助：

>对所有字段使用autopilots,这实际上使第二步减慢了30000ms
>自己解压缩文件并将字节数组解析为VTD,这没有任何区别
>使用BufferedReader readLine()自行循环文件,但这也不够快

有没有人看到加快速度的可能性,还是我需要开始考虑更重的机器/多线程？当然,每分钟850.000行(每天12亿行)很多,但我仍然觉得解析31MB数据不应该花一分钟……