Common methods for Java strings and string buffers __java

common methods for Java strings and string buffers Strings String

a method of judging function

Sample

equals determines whether two strings have the same character sequence string str = "ABCDEF";
Boolean RESULT1 = Str.equals ("abcdef");

Boolean result2 = Str.equals ("ABCdef");

System.out.println ("(equals): Result1 =" + Result1 + ", result2 =" + result2);
Equalsignorecase is the same as equals, but ignores case result1 = str.equalsignorecase ("abcdef");

RESULT2 = Str.equalsignorecase ("ABCdef");

System.out.println ("(equalsignorecase): RESULT1 =" + Result1 + ", result2 =" + result2);
Determines whether the specified string result1 = Str.contains ("A") is included;
RESULT2 = Str.contains ("x");

System.out.println ("(contains): RESULT1 =" + Result1 + ", result2 =" + result2);
StartsWith determines whether to start with the specified string result1 = Str.startswith ("abc");
RESULT2 = Str.startswith ("def");

System.out.println ("(startswith): RESULT1 =" + Result1 + ", result2 =" + result2);
EndsWith to determine whether to end result1 = Str.endswith ("abc") with the specified string;
RESULT2 = Str.endswith ("def");

System.out.println ("(endsWith): RESULT1 =" + Result1 + ", result2 =" + result2); IsEmpty judgment string isNo null RESULT1 = Str.isempty ();
RESULT2 = "". IsEmpty ();

System.out.println ("(isempty): RESULT1 =" + Result1 + ", result2 =" + result2);
CompareTo according to the dictionary order, the Unicode value of two strings per character is judged by the dictionary order, larger than the specified string, returns a positive number, and returns a negative number, equal returns 0 int num1 = Str.compareto ("abcdef");
int num2 = Str.compareto ("Abcdee");
int num3 = Str.compareto ("abcdeg");

System.out.println ("(compareTo): NUM1 =" + Num1 + ", num2 =" + num2 + ", num3 =" + num3);
Comparetoignorecase ignores case, same as CompareTo NUM1 = Str.comparetoignorecase ("ABCdef"); System.out.println ("(comparetoignorecase): NUM1 =" + NUM1);

Run Results

methods that have access to functionality

Demo

Length of string
str = "abcdef";

System.out.println ("(length):" + str.length ());

CharAt obtains the specified position of the character
System.out.println ("(charAt):" + Str.charat (2));

IndexOf gets the first occurrence of the specified string, not finding the return-1
System.out.println ("(indexOf):" + str.indexof ("CD"));

LastIndexOf gets the position of the last occurrence of the specified string, no return-1
System.out.println ("(LastIndexOf):" + str.lastindexof ("de"));

Split based on the specified regular expression, the cutting string, returning the string array
string[] ss = "Abc|def|ghi". Split ("[|]");
System.out.println ("(split):" + arrays.tostring (ss));

Substring intercept string
System.out.println ("(substring):" + str.substring (2)); Intercept from the position of index 2, intercept to the last
System.out.println ("(substring):" + str.substring (2, 4))//intercept from index 2, intercept to index 4, excluding 4 (header not wrapped)

Run Results

a method with transformation function

Sample

GetBytes converts a string into a byte array string
str = "abcdef";
byte[] Bytebuf = Str.getbytes ();
System.out.println ("(getBytes):" + arrays.tostring (bytebuf));

ToCharArray converts a string into a character array
char[] charbuf = Str.tochararray ();
System.out.println ("(ToCharArray):" + arrays.tostring (charbuf));

valueof converts any value/object to a string
System.out.println ("(valueof):"
        + string.valueof (new char[] {);

toUpperCase converts characters to uppercase
System.out.println ("(touppercase):" + str.touppercase ());

toLowerCase converts the string to lowercase
System.out.println ("(tolowercase):" + "ABCdef". toLowerCase ());

Concat stitching two string
str = "AAA". Concat ("CCC");
System.out.println ("(concat):" + str);

Run Results

methods that have replacement functions

Sample

Replace replaces the specified character in the string with the new string
str = "T  abc abc   ";
System.out.println ("(replace):" + str.replace ("A", "X"));

Trim removes the whitespace at both ends of the string
System.out.println (Trim): + Str.trim ());

Run Results
String Buffer Stringbuffer/stringbuilder

Common Methods

Sample

StringBuffer sb = new StringBuffer ();

Gets the initial length of the StringBuffer buffer
System.out.println ("(capacity):" + sb.capacity ());

Append append string
sb.append ("abc");
System.out.println ("(Append):" + SB);

Length gets the actual length of the buffer
System.out.println ("(length):" + sb.length ());

Inserts the data into the buffer at the specified position
sb.insert (1, "XX");
System.out.println ("(insert):" + SB);

Deletecharat deletes the character
Sb.deletecharat (2) of the specified position;
System.out.println ("(Deletecharat):" + SB);

Delete Deletes the specified range of characters
Sb.delete (2, Sb.length ());
System.out.println ("(delete):" + SB);

Replace replacement buffer specified range of string
sb.replace (1, 2, "B");
System.out.println ("(replace):" + SB);

Reverse the string in the inverted buffer
sb.reverse ();
System.out.println ("(reverse):" + SB);

Substring intercepts the string, does not manipulate the original buffer, returns a new string
str = sb.substring (1, 2);
System.out.println ("(substring): SB =" + SB + ", str =" + str);

Run Results

The

stringbuffer and StringBuilder have the same method, except that StringBuffer is thread-Safe , while StringBuilder is thread-unsafe .