java - hashMap的put方法覆盖已存储数据的值

Question

我使用 hashMap 来存储从文件读取的数据(证书详细信息)。键和值存储在 hashMap 中，但调用 put 方法后，所有值都具有最后添加的条目的值。我想这也与 hashmap.get() returning wrong values even though they are all correct in the map但我没有看到我的错误:

HashMap<String, String[]> certDataMap = new HashMap<String, String[]>();
    String line="";
    String bankName = "", validTill = "", fingerPrint = "";
    File certDat = new File(certDataFile);
    int cntEntries=0;
    String[] data = {"dummy", "dummy"};

    if (certDat.exists()) {
        try {
            Scanner scanner = new Scanner(certDat);
            while (scanner.hasNextLine()) {
                line=scanner.nextLine();
                bankName=line.split("\\|")[0];
                validTill=line.split("\\|")[1];
                fingerPrint=line.split("\\|")[2];
                logger.debug("line: {} bankName: {} validTill: {} fingerPrint: {}",line, bankName, validTill, fingerPrint);
                data[0]=validTill;
                data[1]=fingerPrint;
                certDataMap.put(bankName, data);
                debugCertMap();
                cntEntries++;
            }
            scanner.close();
            logger.debug("{} read from {}", cntEntries, certDataFile);
        } catch (IOException e) {
            logger.error(certDataFile,e);
        }
    } else
        logger.error(certDataFile+" not found! New file will be created if certificates were downloaded");

问题是 Jonathan 提到的在循环外部声明字符串数组数据:

        while (scanner.hasNextLine()) {
            line=scanner.nextLine();
            bankName=line.split("\\|")[0];
            validTill=line.split("\\|")[1];
            fingerPrint=line.split("\\|")[2];
            logger.debug("line: {} bankName: {} validTill: {} fingerPrint: {}",line, bankName, validTill, fingerPrint);
            String[] data = {validTill, fingerPrint};
            certDataMap.put(bankName, data);
            debugCertMap();
            cntEntries++;

Answer 1

对象实际上是引用，并且您对每一行使用相同的对象数据。使用新对象。