Use of APIs in java.lang.String

1 /**2 * java.lang.String:3 * Copy the string contents into the byte array;4 * String Connection: One string is appended to another string;5 * Replace: Character substitution, string substitution;6 * match and replace;7 * Multiple types of data are converted into string types;8 * Conversion of strings to character arrays;9 * Determine if a string is included;Ten * byte array and string conversion; One  */ A  PackageLang; -  - Importjava.util.Arrays; the  -  Public classStringdemo - { -      Public Static voidMain (string[] args) +     { -String str = "ASDFGHJ"; +         Char[] ch =New Char[Str.length ()]; A         //Copy the string contents into a byte array atStr.getchars (0, Str.length (), CH, 0); - System.out.println (arrays.tostring (CH)); -          -String str2 =NewString ("123456"); -         //put the string str2 behind the string str - Str2.concat (str); in System.out.println (str2); -          toString STR3 = "123123123"; +         //character substitution, followed by the character replacing the preceding character; -         //returns a new string with the previous string content unchanged theString STR4 = Str3.replace (' 3 ', ' 4 '); *         //print out the result is the same $ System.out.println (STR3);Panax Notoginseng         //The result is 124124124 . - System.out.println (STR4); the         //string Substitution: The following string is replaced with the preceding string +String str8 = Str3.replace ("123", "456"); A         //The result is 456456456 . the System.out.println (str8); +          -String STR9 = "a123b456c789"; $         //match and replace: match to meet the requirements, then replace $String str10 = Str9.replaceall ("[A-Z]", "D"); -         //The result is d123d456d789 . - System.out.println (STR10); the         //match to the first one and replace it, whichever is later matched -String Str11 = Str9.replacefirst ("[A-Z]", "D");Wuyi System.out.println (STR11); the          -         DoubleD = 12.54; Wu         //double type to string -         //There are multiple overloaded methods AboutString STR5 =string.valueof (d); $ System.out.println (STR5); -         //equivalence: As with the above results -String STR6 =double.tostring (d); - System.out.println (STR6); A          +         Char[] C2 = {' A ', ' s ', ' d ', ' F '}; the         //character array into a string -         //there are overloaded methods $String STR7 =string.valueof (C2); the System.out.println (STR7); the          the         //string to character array the         Char[] C3 =Str7.tochararray (); - System.out.println (Arrays.tostring (C3)); in          theString str12 = "123"; the System.out.println (); About         //can only be judged if it contains a string and cannot be judged to contain characters theSystem.out.println (Str12.contains ("12")); the          theString Str13 = "Uhbijn"; +         //string to byte array -         byte[] B =str13.getbytes (); the         //arrays.tostring (): Multiple overloaded methods that can print multiple types of arraysBayi System.out.println (arrays.tostring (b)); the          the         //byte array goto string -String Str14 =NewString (b); - System.out.println (str14); the     } the}

Use of APIs in java.lang.String