First, basic data types and packaging
Packing: basic data types - packaging
Unpacking: Packaging - basic data types
Package com.imooc.wrap; public class WrapTestOne { public static void main (String [] args) { // Packing: converting the basic data types into a packaging @ 1 autoboxing int T1 = 2 ; Integer T2 = T1; // 2. manual packing Integer = T3 new new Integer (T1); // test System.out.println ( "int type variable = T1" + T1); System.out.println ( "Ingeter type variable t2 = "+ T2); System.out.println ( " = Ingeter type variable T3 "+ T3); System.out.println ("=======================" ); // unboxing: converting the base data packaging // 1. automatically unpacking, by assignment = achieve int T4 = T2; // 2. manually unpacking int T5 = t2.intValue (); Double T6 = t2.doubleValue (); // test System.out.println ( "Integer Object type = T2" + T2 ); System.out.println ( "automatically after unpacking, int type object = T4" + T4); System.out.println ( "manually after unpacking, int type object = T5" + T5); the System.out. the println ( "manually unpacking, double type object = T6" + T6); } }
Second, the basic string data type and
Basic data types - String: packaging .toString (basic data types);
String - basic data types: packaging .parseInt (string); / packaging .valueOf (string);
Package com.imooc.wrap; public class WrapTestTwo { public static void main (String [] args) { // basic data type into a string int T1 = 2 ; String T2 = Integer.toString (T1); // Test System .out.println ( "int type to objects of type String = T2" + T2); System.out.println ( "======================= ===== " ); // string into basic data types // the parse 1. wrapper class int T3 = the Integer.parseInt (T2); // 2. valueOf first converted into a string of packaging packaging category, and then complete the basic automatic type conversions unboxing int= T4 Integer.valueOf (T2); // Test System.out.println ( "String type to objects of type int = T3" + T3); System.out.println ( "String type to objects of type int t4 =" + T4); } }