1、第六章JAVA常用类import java.util.regex.*;public class TestString public static void main(String args) /String s = AaaaABBBBcc&%adfsfdCCOOkk99876 _haHA; /int lCount = 0, uCount = 0, oCount = 0; /* for(int i=0; i= a & c =A & c = Z) uCount +; else oCount +; */ /* String sL = abcdefghijklmnopqrstuvwxyz; Strin
2、g sU = ABCDEFGHIJKLMNOPQRSTUVWXYZ; for(int i=0; is.length(); i+) char c = s.charAt(i); if(sL.indexOf(c) != -1) lCount +; else if (sU.indexOf(c) != -1) uCount +; else oCount +; */ /* for(int i=0; is.length(); i+) char c = s.charAt(i); if(Character.isLowerCase(c) lCount +; else if (Character.isUpperCa
3、se(c) uCount +; else oCount +; System.out.println(lCount + + uCount + + oCount); */ String s = sunjavahpjavaokjavajjavahahajavajavagoodjava; String sToFind = java; int count = 0; int index = -1; while(index = s.indexOf(sToFind) != -1) s = s.substring(index + sToFind.length(); count +; System.out.pri
4、ntln(count); /*public class TestStringCase public static void main(String args) String s = ABAabb$&$#BAAb898B#%aa; int cU = 0, cL = 0, cO = 0; for(int i=0; i= A & c = a & c =z) cL +; else cO +; System.out.println(大写： + cU); System.out.println(小写： + cL); System.out.println(其他： + cO); /*/在windows和linu
5、x系统下都写“/”最保险这个代表转义字符，两个连着写 代表一个,package bjsxt;import java.io.*;public class TestFile public static void main(String args) String separator = File.separator;/使用指定的文件分割符 String filename = myfile.txt; String directory = mydir1 + separator + mydir2; /String directory = mydir1/mydir2; /String directory =
6、 mydir1mydir2; File f = new File(directory, filename); if (f.exists() System.out.println(文件名： + f.getAbsolutePath(); System.out.println(文件大小： + f.length(); else f.getParentFile().mkdirs(); try f.createNewFile(); catch (IOException e) e.printStackTrace(); import java.io.*;public class FileList public
7、 static void main(String args) File f = new File(d:/A); System.out.println(f.getName(); tree(f, 1); private static void tree(File f, int level) /leven是递归的层数 String preStr = ; for(int i=0; ilevel; i+) preStr += ; File childs = f.listFiles(); for(int i=0; ichilds.length; i+) System.out.println(preStr
8、+ childsi.getName(); if(childsi.isDirectory() tree(childsi, level + 1); public class TestEnum public enum MyColor red, green, blue ; public enum MyDoorOpener me, mywife; public static void main(String args) MyColor m = MyColor.red; switch(m) case red: System.out.println(red); break; case green: System.out.println(green); break; default: System.out.println(default); System.out.println(m);
