黑马程序员_java基础String的常见操作

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class StringMethodDemo{public static void method_get(){String str = "Zhangsa,lisi,wangwu";String[] arr = s.split(",");for (int x=0;x<arr.length;x++){sop(arr[x]);}}public static void method_replace(){String s = "hello java";String s1 = s.replace("java","world");sop("s="+s);sop("s1="+s1);}public static void method_trans(){char[] arr = {'a','b','c','d','e','f'};String s = new String(arr,1,3);sop("s="+s);String s1 = "zxcvbnm";char[] chs = s1.toCharArray();for(int x=0;x<chs.length;x++){sop("ch="+chs[x]);}}public static void method_is(){String str = "ArrayDemo.java"sop(str.startsWith("Array"));sop(str.endsWith(".java"));sop(Str.contains(".java"));}public static void method_get(){String str = "abcdeakpf";sop(str.length());sop(str.charAt(4));sop(str.indexOf('m',3));sop(str.lastIndexOf("a"));}public static void main(String[] args){method_split()}public static void sop(Object obj){System.out.println(obj);}}//练习一，去除字符串两端空格。class StringTest{public static void sop(String str){System.out.println(str);}public static void main(String[] args){String s= "    ab cd    "；sop("("+s+")")s = myTrim(s);sop("("+s+")")}public static String myTrim(String str){int start = 0,end =str.length()-1;while(Strart<=end && str.charAt(start)==' ')start++;while(Strart<=end && str.charAt(end)==' 'end--;return str.substring(start,end+1);}}while（S.charAt(pos)=='-')pos++;int x = s.length()-1;while(s.charAt(x)=='')x--;//练习二：将字符串反转。思路：1 将字符串变成数组2 对数组反转3 将数组变成字符串public static String reverseString(String s){//字符变数组char[] chs = s.toCharArray();// 反转数组。reverse(chs);//数组变成字符串return new String}private static void reverse(char[] arr){for(int start=0,end=arr.length-1;start<end;start++,end--){swap(arr,start,end);}}private static void swap(char[] arr,int x,int y){char temp = arr[x];arr[x] = arr[y];arr[y] = temp;}//练习三 获取一个字符串在另一个字符串中出现的次数。public static int getSubCount(String str,String key){int count = 0;int index = 0;while(str.indexOf(key))!=-1){sop("str="+str);strSubString（index+key.length());count++;}return count;}public static void main(String[] args){String str = "abkkcdkkefkkskk";sop("count="+getSubCount(str,"kk"));//sop("count="+getSubCount_2(str,"kk"));}public static void sop(String str){System.out.println(str);}}//练习四 获取两个字符串中最大相同数的整数 思路：1 将短的那个子串按照长度递减的方式获取到；2将每获取到的子串去长串中判断是否包含，如包含，找到！public static String getMaxSubString(String s1,String s2){/*String max = "",min = "";max = s1.length()>s2.length())?s1:s2;min = (max==s1)?s2:s1sop("max="+max+"...min"+min)*/for(int x=0;x<s2.length();x++){for (int y=0;z=s2.length()-x;z!=s2.length()+1;y++,z++){String temp = s2.substring(y,z);//sop(temp);if (s1.contains(temp))//if(s1.indexOf(temp)!=-1return temp;}}return"";}public static void main(String[] args){String s1 = "abcwerthelloyuiodef";String s2 = "cvhellobnm";sop(getMaxSubString(s1,s2));}public static void sop(String str){System.out.println(str);}}