Question

我只是想用\\

替换字符串\\\\

以下是程序，但它正在终止

String path="\\dctmadmin\\Human Resource\\Training\\Procedures\\Formalities\\Legalities\\Material";         

long start = System.currentTimeMillis();
// replace this string \\ with \\\\
String formatedPath = path.replaceAll("\\\\", "\\\\\\\\");
System.out.println(" string after formatting using replaceAll = "+formatedPath);
long end = System.currentTimeMillis();
System.out.println(" time take in milli seconds for String.replaceAll = "+Long.toString(end-start) );

请让我知道我正在做的错误。

Answer 1

对于不需要正则表达式功能的文字字符串替换，您应该使用replace而不是replaceAll，因为它更简单，更有效。

// replace single backslash with double
String formatedPath = path.replace("\\", "\\\\");

Answer 2

您的真实字符串只包含一个\。测试

System.out.println("\\dctmadmin\\Human Resource\\Training\\Procedures\\Formalities\\Legalities\\Material");

所以你的replaceAll运行正常，如果它在System.out.println（＆＃34;你的字符串＆＃34; .replaceAll（...））;

时返回double \\

Answer 3

尝试

String path = 
    "\\dctmadmin\\Human Resource\\Training\\Procedures\\Formalities\\Legalities\\Material";


long start = System.currentTimeMillis();
// replace this string \\ with \\\\

String formatedPath = path.replaceAll("\\\\", "\\\\\\\\\\\\\\\\");

System.out.println(" string after formatting using replaceAll = " + 
                   formatedPath);


long end = System.currentTimeMillis();

System.out.println(" time take in milli seconds for String.replaceAll = " + Long.toString(end - start));

System.out.println(" path  "+formatedPath);

Answer 4

在你的字符串中，当你说\它实际意味着\由另一个\转义时，它正在正确地替换它。

String path="\\dctmadmin\\Human Resource\\Training\\Procedures\\Formalities\\Legalities\\Material";

         System.out.println("String before: "+ path);
        long start = System.currentTimeMillis();
        // replace this string \\ with \\\\

          String formatedPath = path.replaceAll("\\\\", "\\\\\\\\");

          System.out.println(" string after formatting using replaceAll = "+formatedPath);

输出我

   String before:  \dctmadmin\Human Resource\Training\Procedures\Formalities\Legalities\Material

     string after formatting using replaceAll = \\dctmadmin\\Human Resource\\Training\\Procedures\\Formalities\\Legalities\\Material
     time take in milli seconds for String.replaceAll = 2

Answer 5

你没事。在Java中，字符串\\代表一个反斜杠，在正则表达式中它是非String转义。

    String formatedPath = path.replaceAll("\\\\", "\\\\\\\\");
    System.out.println("path         = " + path);
    System.out.println("formatedPath = " + formatedPath);

给出

path         = \dctmadmin\Human Resource\Training\Pr...s\Form...s\L...s\Material
formatedPath = \\dctmadmin\\Human Resource\\Training\\Pr..s\\Form...s\\Material

Answer 6

的输出

string after formatting using replaceAll = \\dctmadmin\\Human Resource\\Training\\Procedures\\Formalities\\Legalities\\Material

是对的。看起来它没有改变，因为你正在贬低你的原文中的'\'被转义的事实：）

string.replaceAll的问题

6 个答案: