char type can represent only one character. To represent a string of characters, use the String data type.
String class is a Java library of predefined classes, not a basic type is a reference type.
Simple method String object:
- length () Returns the number of characters in a string
- chatAt (index) Returns the specified bit character string s
- the concat (s1) is connected to this string s1, it returns a new string
- toUpperCase () Returns a new string in which all capital letters
- the toLowerCase () Returns a new string in which all lowercase
- trim () Returns a new string, on both sides of whitespace removed
The connection string: String s3 = s1.concat (s2);
s3 = s1 + s2;
String comparison:
- the equals (s1) and the string is equal to s1, returns true
- equalsIgnoreCase (s1) and the string is equal to s1, returns true, case insensitive
- Integer compareTo (s1) returns a value greater than 0, equal to 0, less than 0
- compareToIgnoreCase (s1) returns a value greater than 0, equal to 0, an integer less than zero, a case-insensitive comparison
- startsWith (prefix) If the string begins with a specific prefix, returns true
- endsWith (suffix) if specific suffix string end, returns true
- the contains (s1) if s1 is a substring of the character string, returns true
"==" operator: only determining whether two objects point to the same string.
equals (): determine the contents of the character variables are equal.
Obtain substring:
- the substring (beginIndex) Returns substrings, the beginning and end of the character from the character beginIndex
- the substring (beginIndex, endIndex) Note that all lowercase characters from beginIndex to endIndex-1 is, [,)
Character string number conversion between:
- Converted to int type:
- Converted to double:
- Converting the digital number to a string:
