Java DNS API 不工作

Question

我似乎无法弄清楚如何让这段代码正常工作。难道我做错了什么？程序在 Record[] 记录上失败 =lookup.run();行。

import java.util.Iterator;

    import org.xbill.DNS.ARecord;
    import org.xbill.DNS.Lookup;
    import org.xbill.DNS.Record;
    import org.xbill.DNS.TXTRecord;
    import org.xbill.DNS.TextParseException;
    import org.xbill.DNS.Type;
    Lookup lookup;
    try {
        lookup = new Lookup("google.com", Type.ANY);
        Record[] records = lookup.run();

        if (lookup.getResult() == Lookup.SUCCESSFUL) {
            String responseMessage = null;
            String listingType = null;
            for (int i = 0; i < records.length; i++) {
                if (records[i] instanceof TXTRecord) {
                    TXTRecord txt = (TXTRecord) records[i];

                    for (Iterator j = txt.getStrings().iterator(); j.hasNext();) {
                        responseMessage += (String) j.next();
                    }
                } else if (records[i] instanceof ARecord) {
                    listingType = ((ARecord) records[i]).getAddress()
                            .getHostAddress();
                }
            }
        }
    }catch (TextParseException e) {
        e.printStackTrace();
    }

Answer 1

你说它不起作用是什么意思？请按照前面的要求粘贴任何异常跟踪。我能够很好地运行代码，我将输出添加到记录中以查看结果。代码如下：

import java.util.Iterator;
import org.xbill.DNS.ARecord;
import org.xbill.DNS.Lookup;
import org.xbill.DNS.Record;
import org.xbill.DNS.TXTRecord;
import org.xbill.DNS.TextParseException;
import org.xbill.DNS.Type;

public class DNS {

    public static void main(String[] args) {
        try {
            Lookup lookup = new Lookup("google.com", Type.ANY);
            Record[] records = lookup.run();

            if (lookup.getResult() == Lookup.SUCCESSFUL) {
                String responseMessage = null;
                String listingType = null;
                for (int i = 0; i < records.length; i++) {
                    if (records[i] instanceof TXTRecord) {
                        TXTRecord txt = (TXTRecord) records[i];
                        for (Iterator j = txt.getStrings().iterator(); j
                                .hasNext();) {
                            responseMessage += (String) j.next();
                        }
                        System.out.println("TXRecord " + responseMessage);
                    } else if (records[i] instanceof ARecord) {
                        listingType = ((ARecord) records[i]).getAddress()
                                .getHostAddress();
                        System.out.println("ARecord address : " + listingType);
                    }
                }
            }
        } catch (TextParseException e) {
            e.printStackTrace();
        }
    }
}

这是输出：

ARecord address : 74.125.224.49
ARecord address : 74.125.224.51
ARecord address : 74.125.224.52
ARecord address : 74.125.224.48
ARecord address : 74.125.224.50
TXRecord nullv=spf1 include:_netblocks.google.com ip4:216.73.93.70/31 ip4:216.73.93.72/31 ~all