Java---String class

 Packagesad;//common methods of the String classImportJava.util.Scanner; Public classers { Public Static voidMain (string[] args) {factory.choose (); }}classfactory{Static voidChoose () {intChoose=0; Scanner SC=NewScanner (system.in);  while(true) {System.out.println ("Please enter the action you want:"); System.out.print ("1: Extract a character from a string \n2: strings and Arrays convert \n3: Determine if a string is included (lookup) \n4: string substitution \n5: Intercept string \n6: Split string \ n"); Choose=Sc.nextint (); Switch(Choose) { Case1:            NewStringcharat ();  Break;  Case2:            NewStringarray ();  Break;  Case3:            NewStringsearch ();  Break;  Case4:            NewStringReplace ();  Break;  Case5:            NewSubString ();  Break;  Case6:            NewStringsplit ();  Break; default:                 Break; }        }    }}classstringcharat{ PublicStringcharat () {Scanner SC=NewScanner (system.in); System.out.println ("Please enter a string:"); String Str=Sc.next (); System.out.println ("The 0th character is:" +str.charat (0));//remove a character from a stringSystem.out.println ("The second character is:" +str.charat (2)); }}classstringarray{ PublicStringarray () {Scanner SC=NewScanner (system.in); System.out.println ("Please enter a string:"); String Str=Sc.next (); CharData[] = Str.tochararray ();//array of string turnsSystem.out.println ("After the string is converted to an array:");  for(inti=0;i<data.length;i++) {System.out.println (Data[i]+" "); } System.out.println ("After the array is converted to a string:"); System.out.println (NewString (data));//Array to stringSystem.out.println ("begins to intercept a string of a certain length from a character in the array:"); System.out.println ("Please enter the starting position:"); intStart =Sc.nextint (); System.out.println ("Please enter length:"); intLength =Sc.nextint (); System.out.println (NewString (data,5,4));//starting point, lengthSystem.out.println ("____________________"); }}classstringsearch{ PublicStringsearch () {//TODO auto-generated Constructor stubString str = "***hello**word"; if(Str.contains ("Hello"))//determine if a string is included{System.out.println ("contains the specified string"); }        if(Str.indexof ("E")!=-1)//determines whether the specified character is present from the beginning, and the return value is the position{System.out.println ("String Position:" +str.indexof (' E ')); }        if(Str.indexof ("E", 6) ==-1)//To find out if a character is present at the beginning of the specified position{System.out.println ("Does not exist"); }        if(Str.lastindexof ("E", 12) ==-1)//find out if a character is present from the beginning of the specified position{System.out.println ("Does not exist"); }        if(Str.startswith ("*"))//determine whether to start with a character{System.out.println ("True"); }        if(Str.startswith ("*", 2))//determines whether a specified position is a character or a segment of characters{System.out.println ("True"); }        if(Str.endswith ("D"))//determines whether a character ends{System.out.println ("True"); } System.out.println ("____________________"); }}classstringreplace{StringReplace () {String str= "Helloword"; System.out.println (Str.replaceall ("O", "* * *"));//Replace all occurrences of a character withSystem.out.println (Str.replacefirst ("L", "_"));//replaces the first occurrence of a specified characterSystem.out.println ("____________________"); }}classsubstring{ PublicSubString () {String str= "Hellojava"; System.out.println (Str.substring (5));//intercepts a string from the specified position to the endSystem.out.println (str.substring (0,5));//intercepts a string at a specified positionSystem.out.println ("____________________"); }}classstringsplit{ PublicStringsplit () {String str= "Hello World Hello java"; string[] Data= Str.split ("");  for(inti=0;i<data.length;i++) {System.out.println (data[i]); } System.out.println ("____________________"); String data2[]= Str.split ("", 3);  for(inti=0;i<data2.length;i++) {System.out.println (data2[i]); }        }}

Java---String class