java-基于重复元素将大XML文件拆分为小块

考虑以下具有500 MB数据的XML

<?xml version="1.0" encoding="UTF-8"?>
<Parents>
  <process  Child ="A">...</process>
  <process  Child="B">...</process>
  <process  Child="A">...</process>
  <process  Child="C">..</process>
  <process Child=...
  </process>
 <\Parents>

此xml具有多个带有标记“ A”或“ B”或其他标记的子属性,我想为“ A”,“ B”,“ C”或其他诸如expamle_A.xml,example_B.xml等创建单独的XML.正在为每个子属性创建单独的xml敌人,这意味着如果我们有500个子属性,则其将创建500个xml.

public static void main(String args[]) {
        try {
            VTDGen v = new VTDGen();
            if (v.parseFile("C:\\..\\example.xml", true)) {
                VTDNav vn = vg.getNav();
                AutoPilot ap = new AutoPilot(vn);
                ap.selectXPath("/Parents/child");
                int  chunk = 0;
                while (( ap.evalXPath()) != -1) {
                    long frag = vn.getElementFragment();
                    (new FileOutputStream("C:\\....\\result" + chunk + ".xml")).write(vn.getXML().getBytes(), (int) frag,
                            (int) (frag >> 32));
                    chunk++;
                }
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
}

现在的事情是,我想基于实例的同一组的子对象属性拆分文件,“ A”的所有子对象都应以相同的方式在example_A.xml文件中用于B,C和其他.

解决方法:

这是对现有代码的非常简单的修改.实际上,有多种方法可以做到这一点.我只是向您展示其中之一：通过使用VTDNav的getAttrVal method()显式比较attr val.

public static void main1(String args[]) {
    try {
        VTDGen vg = new VTDGen();
        if (vg.parseFile("C:\\..\\example.xml", true)) {
            VTDNav vn = vg.getNav();
            AutoPilot ap = new AutoPilot(vn);
            ap.selectXPath("/Parents/process");
            int  chunk = 0;
            FileOutputStream fopsA=(new FileOutputStream("C:\\....\\resultA" + chunk + ".xml"));
            fopsA.write("<Parent>\n".getBytes());
            FileOutputStream fopsB=(new FileOutputStream("C:\\....\\resultB" + chunk + ".xml"));
            while (( ap.evalXPath()) != -1) {
                long frag = vn.getElementFragment();
                int i=vn.getAttrVal("Child");
                if (i==-1) throw new NavException("unexpected result");
                if  (vn.compareTokenString(i,"A")==0){

                    fopsA.write(vn.getXML().getBytes(), (int) frag,
                        (int) (frag >> 32));

                }else if  (vn.compareTokenString(i,"B")==0){

                    fopsB.write(vn.getXML().getBytes(), (int) frag,
                            (int) (frag >> 32));
                }
                chunk++;
            }

            fopsA.write("</Parent>\n".getBytes());
            fopsB.write("</Parent>\n".getBytes());
        }
    } catch (Exception ex) {
        ex.printStackTrace();
    }

标签：vtd-xml,stax,xml,java,xml-parsing
来源： https://codeday.me/bug/20191025/1931695.html