Coding Practice--java-string-api-Practice __ajax

Welcome to visit the blog initialization (constructors) various initialization methods

String str1 = new string ();
System.out.println (STR1);

Char[] arr = {' A ', ' B ', ' C '};
String str2 = new string (arr);
System.out.println (STR2);

String STR3 = "Zhang";
System.out.println (STR3);

String STR4 = new String ("Xuezhi");
System.out.println (STR4);

String Method Str.charat ()Returns the character at the specified position

String str1 = new String ("Hello, world!");

System.out.println (Str1.charat (4));

Str.codepointat ()Returns the Unicode encoding of the specified position character

public static void Main (string[] args) {
String str1 = new String ("Hello, world!");

System.out.println (Str1.codepointat (4)); o
System.out.println (Str1.codepointat (8));//o

Str.codepointbefore ()Returns the Unicode encoding of the character at the previous position in the specified position

String str1 = new String ("Hello, world!");

System.out.println (Str1.codepointbefore (3)); L
System.out.println (Str1.codepointbefore (4));//l

Str.codepointcount ()Returns the number of encodings for Unicode within a specified range

String str1 = new String ("Hello, world!");

System.out.println (Str1.codepointcount (0, 2)); He

Str.compareto ()Compares a dictionary order of two strings and returns 0 when equal

String str1 = "ba";
String str2 = "ba";
String STR3 = "be";

System.out.println (Str1.compareto (str2));
System.out.println (Str1.compareto (STR3));

str.comparetoignorecase ()Does not distinguish size form, compares the dictionary order of two strings, returns 0 when equal

String str1 = "ba";
String str2 = "be";

System.out.println (Str1.compareto (str2));
Case-insensitive
System.out.println (Str1.comparetoignorecase (str2));

Str.concat ()string concatenation

String str1 = "Hello";
String str2 = "world!";

String STR3 = Str1.concat (STR2); Connect
String STR4 = str1 + str2 via concat ();  Through + Connect
System.out.println (STR3);
System.out.println (STR4);

str.contains ()To determine if a string contains another string

String str1 = "Hello";
String str2 = "ll";
String STR3 = "AB";

System.out.println (Str1.contains (str2));
System.out.println (Str1.contains (STR3));

str.contentequals ()To determine whether two strings are equal

String str1 = "Hello";
String str2 = "ll";
StringBuffer STR3 = new StringBuffer ("Hello");

System.out.println (Str1.contentequals (str2));   String
System.out.println (str1.contentequals (STR3));   StringBuffer

str.copyvalueof ()Converts a character array to a string

Char[] arr = {' h ', ' e ', ' l ', ' l ', ' o '};
String str1 = string.copyvalueof (arr);
String str2 = string.copyvalueof (arr, 2, 2);

System.out.println (STR1);
System.out.println (STR2);

Str.endswith ()To determine whether to end with a substring

String str1 = "Hello, world";

System.out.println (Str1.endswith ("World"));

str.equals () & Str.equalsignorecase ()Sentenced etc

String str1 = "Hello, world";
String str2 = "Hello, world";

System.out.println (Str1.equals (str2));
System.out.println (Str1.equalsignorecase (str2));

Str.format ()String formatting

String str1 = String.Format ("Hi,%s!", "Xuezhi");
String str2 = String.Format ("Price:%d", 4);
String STR3 = String.Format ("Price:%.2f yuan", 4.5);

System.out.println (STR1);
System.out.println (STR2);
System.out.println (STR3);

str.getbytes ()Encodes a string into a byte array

String str1 = "abcdef";
byte[] BArr = Str1.getbytes ();
Print for
(byte Item:barr) 
    System.out.print (item + "");

Str.hashcode ()Returns its hash code

String str1 = "abcdef";

System.out.println (Str1.hashcode ());

Str.indexof ()Returns where the character first appears

String str1 = "ABCABC";

The position of System.out.println ("a") is: "+ str1.indexof (" a "));
System.out.println ("A's position is:" + str1.indexof (' a '));

The position of the System.out.println ("a") is: "+ str1.indexof (" a ", 2));

Str.lastindexof ()Returns where the character last appears

String str1 = "ABCABC";

The last position of the System.out.println ("a") is: "+ str1.lastindexof (" a "));
The last position of the System.out.println ("a") is: "+ str1.lastindexof (' a ')");

The last position of the System.out.println ("a") is: "+ str1.lastindexof (" a ", 2));

Str.intern ()。 Intern () returns equal value only if two strings are equal

String str1 = "ABCABC";

String str2 = Str1.intern ();

System.out.println (STR2);

Str.isempty ()Determines whether a string is empty

String str1 = "abc";
String str2 = "";

System.out.println (Str1.isempty ());
System.out.println (Str2.isempty ());

str.length ()Returns the length of a string

String str1 = "abc";
String str2 = "";

System.out.println (Str1.length ());
System.out.println (Str2.length ());

str.matches ()Whether to match the given regular expression

String str1 = "Hello, world";

System.out.println (Str1.matches ("(. *) World (. *)"));

str.replace ()Character substitution or string substitution

String str1 = "Hello, world";
String str2 = str1.replace (' h ', ' H '); Char
string str3 = Str1.replace ("World", "World");//String

System.out.println (str2);
System.out.println (STR3);

Str.replaceall ()Replace all the regular expressions

String str1 = "Hello, world";
String str2 = Str1.replaceall ("L", "L"); Char

System.out.println (STR2);

Str.replacefirst ()Replace the first string

String str1 = "Hello, world";
String str2 = Str1.replacefirst ("L", "L"); 

System.out.println (STR2);

Str.split ()String segmentation

String str1 = "ABCABCABCABC";

string[] Strarr = Str1.split ("a");
System.out.println (strarr.length);
for (String Item:strarr) 
    System.out.println (item);

string[] strArr2 = Str1.split ("A", 3);
System.out.println (strarr2.length);

for (String item:strarr2) 
    System.out.println (item);

Str.startswith ()Determines whether a string starts with a substring

String str1 = "Hello, world!";

System.out.println (Str1.startswith ("Hello"));
System.out.println (Str1.startswith ("World", 7));/offset

str.subsequence ()Returns the sequence of characters for a specified interval

String str1 = "Hello, world!";

System.out.println (Str1.subsequence (7, 12));

str.substring ()Returns the string for the specified interval

String str1 = "Hello, world!";

System.out.println (str1.substring (7));
System.out.println (str1.substring (7));

Str.tochararray ()Converts a string into a character array

String str1 = "Hello";

char[] Chararr = Str1.tochararray ();

for (char Item:chararr) 
    System.out.print (item + "");

str.tolowercase ()Convert to lowercase form

String str1 = "abc DEF";

System.out.println (Str1.tolowercase ());

str.touppercase ()Convert to Capital form

String str1 = "abc DEF";

System.out.println (Str1.touppercase ());

Str.trim ()Remove whitespace from the beginning and end of a string

String str1 = "  abc def  ";

System.out.println (Str1.trim ());

str.valueof ()Convert various types of data into strings

Char[] Chararr = {' A ', ' B ', ' C '};

System.out.println (String.valueof (false));
System.out.println (string.valueof (' a '));
System.out.println (string.valueof (Chararr));
SYSTEM.OUT.PRINTLN (string.valueof (4.5));
System.out.println (String.valueof (4));