java - 字符串包含相同的字符但仍然不同

Question

<分区>

Answer 1

如果我执行这段代码:

public static void main(String[] args) {
    load_Players("Netherlands");
}

private static void load_Players(String team_Name) {
    String path = "team_Netherlands.txt"; // works
    String path2 = "team_" + team_Name + ".txt"; // doesn't work?
    System.out.println("are " + path + " and " + path2 + " the same? " + path.equals(path2));
}

一切都按预期工作，所以...出了什么问题？

---

正如您在日志中看到的，首先荷兰不是蓝色的，这意味着解析器发现了一些不同的东西。

可疑吗？

---

支票:

当我将这部分代码粘贴到我的 eclipse 中时:

team_Netherlands.txt and team_Netherlands.txt 

保存时出现此错误:

如果我选择选项选择它选择的第一个字符:

System.out.println("team_Netherlands.txt".equals("team_Netherlands.txt"));
                                                       ↑ this one!!!

所以你传递了错误的编码，你可以用这个 fragment 来检查:

public static void main(String[] args) {
    String rightString = "_Netherlands.txt";
    String wrongString = "_Netherlands.txt";

    System.out.println("WRONG HASH");
    System.out.println(rightString.hashCode());
    System.out.println("\nRIGHT HASH");
    System.out.println(wrongString.hashCode());

    System.out.println("\nRIGHT");
    printChars(rightString);

    System.out.println("\n\nWRONG");
    printChars(wrongString);

}

private static void printChars(String s) {
    for (Character c : s.toCharArray()) {
        System.out.print((int) c + " ");
    }
}

输出:

WRONG HASH
1109617587

RIGHT HASH
-428164238

RIGHT
95 78 101 116 104 101 114 108 97 110 100 115 46 116 120 116 

WRONG
95 65279 78 101 116 104 101 114 108 97 110 100 115 46 116 120 116 
// ↑ here!!

---

解决方案:( source )

• 使用来自 Apache IO Commons 的 BOMInputStream

• 手动处理(快速简便的方法):

  private static String clean(String s) throws Exception {
      InputStream is = new ByteArrayInputStream(s.getBytes());
      try (BufferedReader br = new BufferedReader(new InputStreamReader(is))) {
          // BOM marker will only appear on the very beginning
          br.mark(4);
          if ('\ufeff' != br.read())
              br.reset(); // not the BOM marker
  
          return br.readLine();
      }
  }
  

测试它!

public static void main(String[] args) throws Exception {
    String rightString = "Netherlands.txt";
    String wrongString = "Netherlands.txt";

    System.out.println("\nCOMPARE");
    System.out.println(rightString.equals(wrongString));
    System.out.println("\nCLEAN COMPARE");
    System.out.println(clean(rightString).equals(clean(wrongString)));

    System.out.println("\nRIGHT");
    printChars(clean(rightString));

    System.out.println("\n\nWRONG");
    printChars(clean(wrongString));
}

private static String clean(String s) throws Exception {
    InputStream is = new ByteArrayInputStream(s.getBytes());
    try (BufferedReader br = new BufferedReader(new InputStreamReader(is))) {
        // BOM marker will only appear on the very beginning
        br.mark(4);
        if ('\ufeff' != br.read())
            br.reset(); // not the BOM marker

        return br.readLine();
    }
}

private static void printChars(String s) {
    for (Character c : s.toCharArray()) {
        System.out.print((int) c + " ");
    }
}

输出:

COMPARE
false

CLEAN COMPARE
true

RIGHT
78 101 116 104 101 114 108 97 110 100 115 46 116 120 116 

WRONG
78 101 116 104 101 114 108 97 110 100 115 46 116 120 116