Java Learning Lesson 28th (Common Object API)-String class

Multithreading to the beginning of the common object API involved, back also to back down!!!

Future development, meet the most object is the text, that is, the string

String class

A string is a special object

Once the string is initialized, it cannot be changed.

First, the characteristics

public class Main {public static void main (string[] args) {Demo1 (); System.out.println ("--------------");D Emo2 ();} /* Demonstrates the first definition of a string and defines the character of the string constant pool */private static void Demo1 () {string S1 = "ASD"; s1 = "SD";//s1 is just a reference to the string, and the string "ASD" itself is not variable string S2 = new String ("SDF"); System.out.println (s1); s2 = "SD"; System.out.println (S2==S1);//s1 and S2 actually point to the same address value//sd stored in the buffer (string constant pool)//If not, create a second definition of the}/* demo string without creating it, */public static void Demo2 () {String s = "abc";//Creates an object in a string constant pool string S1 = new String ("abc");//not created in the string constant pool, create object two objects in heap memory//one is S1 a "ABC" System.out.println (s = = S1);//false, the address value of the comparison is not the same System.out.println (S.equals (S1));//true/* equals in the String class has a copy of equals in object that establishes the string class * its own judgment string object is the same * that is, compare string content */system.out.println ("s =" +s); System.out.println ("S1 =" +s1);}}

Second, the structure function

public class Main{public static void Main (string[] args) {StringconstructorDemo1 (); Chardemo ();} public static void StringconstructorDemo1 () {string s = new string ();//equivalent to string s = ""; Address value not equal, string s = nullbyte[] s UB = {97,66}; string S1 = new String (sub); System.out.println ("S1 =" +s1);} public static void Chardemo () {char[] ch = {' A ', ' B ', ' C ', ' d ', ' e ', ' f '}; String string = new string (ch);//converts the array into a string, only Byte and charSystem.out.println ("string =" +string); String string1 = new string (ch,0,3);//3 characters System.out.println from 0 corners ("string1 =" +string1),//string class remaining method, check manual}

Not finished ....

Java Learning Lesson 28th (Common Object API)-String class