Java Fundamentals Hardening 65: Introduction of basic type wrapper classes

1. Basic type Packing class overview

(1) The advantage of encapsulating a basic data type as an object is that more functional methods can be defined in the object to manipulate the data.

(2) One of the most common operations: a conversion between a basic data type and a string.

(3) Correspondence of basic types and packaging classes

byte, short, Integer, Long, Float, Double, Character, Boolean

In order to perform more operations on the basic data types and to operate more conveniently, Java provides the corresponding class type--------wrapper class type for each of the basic data types.

2. Case Introduction:

1  Packagecn.itcast_01;2 3 /*4 * Demand 1: I ask you to put 100 of this data binary, octal, hexadecimal calculation out5 * Demand 2: I ask you to determine whether a data is within the range of int. 6 * First of all you know the scope of int is how big?7  * 8 * For more operations on basic data types and easier operation, Java provides the corresponding class type for each of the basic data types. The wrapper class type. 9 * byte byte Ten * Short   short One * int Integer  A * Long long  - * Float float  - * Double double  the * Char Character  - * Boolean boolean  -  *  - * Used for conversions between basic data types and strings.  +  */ -  Public classIntegerdemo { +      Public Static voidMain (string[] args) { A         //No, the trouble is coming. at         //Public static String tobinarystring (int i) -System.out.println (integer.tobinarystring (100)); -         //Public static String tooctalstring (int i) -System.out.println (integer.tooctalstring (100)); -         //Public static String tohexstring (int i) -System.out.println (integer.tohexstring (100)); in  -         //Public static final int max_value to System.out.println (integer.max_value); +         //Public static final int min_value - System.out.println (integer.min_value); the     } *}

Operation Result:

Java Fundamentals Hardening 65: Introduction of basic type wrapper classes