Manipulating Strings - Java Tutorial 5.0 英文版

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Trail: Learning the Java Language
Lesson: Object Basics and Simple Data Objects

Manipulating Strings

The String class has several methods that appear to modify a string. Of course, strings can't be modified, so what these methods really do is create and return a second string that contains the result, as indicated in the following table.
Methods in the String Class for Manipulating Strings
Method Description
String concat(String)
Concatenates the String argument to the end of this string. This is equivalent to the + operator for strings:
System.out.println("Customer: " + getNextCustomer());
If the length of the argument is 0, the original string object is returned.
String[] split(String, int)
String[] split(String) Searches for a match as specified by the string argument (which contains a regular expression) and splits this string into an array of strings accordingly. The optional integer argument specifies the maximum size of the returned array. For more information on how to use the API for pattern matching, see Regular Expressions .

CharSequence subSequence(int, int) Returns a new character sequence constructed from the beginning index (inclusive) up until the ending index (exclusive).

String trim() Removes white space from both ends of this string.

String toLowerCase() String toUpperCase() Converts this string to lower- or uppercase. If no conversions are necessary, these methods return the original string.

Methods in the `String` Class for Manipulating Strings
Method	Description
`String concat(String)`	Concatenates the String argument to the end of this string. This is equivalent to the `+` operator for strings: System.out.println("Customer: " + getNextCustomer()); If the length of the argument is 0, the original string object is returned.
`String[] split(String, int)` `String[] split(String)`	Searches for a match as specified by the string argument (which contains a regular expression) and splits this string into an array of strings accordingly. The optional integer argument specifies the maximum size of the returned array. For more information on how to use the API for pattern matching, see Regular Expressions .
`CharSequence subSequence(int, int)`	Returns a new character sequence constructed from the beginning index (inclusive) up until the ending index (exclusive).
`String trim()`	Removes white space from both ends of this string.
`String toLowerCase() String toUpperCase()`	Converts this string to lower- or uppercase. If no conversions are necessary, these methods return the original string.

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