一、java版
单例类 Singleton.java :
public class Singleton {
private static Singleton instance = null;
private Singleton(){
}
public static Singleton getInstance(){
if(instance == null){
instance = new Singleton();
}
return instance;
}
}测试类 Test.java :
public class Test {
public static void main(String[] args) {
Singleton singleton = Singleton.getInstance();
System.out.println(singleton);
Singleton singleton2 = Singleton.getInstance();
System.out.println(singleton2);
}
}测试结果：
com.hejinlai.singleton.Singleton@6345e044
com.hejinlai.singleton.Singleton@6345e044
二、c++版
单例类 Singleton.h Singleton.cpp :
//
// Singleton.h
// Pattern
//
// Created by hejinlai on 13-8-6.
// Copyright (c) 2013年 yunzhisheng. All rights reserved.
//
#ifndef __Pattern__Singleton__
#define __Pattern__Singleton__
#include <iostream>
class Singleton {
public:
static Singleton * getInstance();
private:
Singleton();
static Singleton * instance;
};
#endif /* defined(__Pattern__Singleton__) *///
// Singleton.cpp
// Pattern
//
// Created by hejinlai on 13-8-6.
// Copyright (c) 2013年 yunzhisheng. All rights reserved.
//
#include "Singleton.h"
Singleton * Singleton::instance = NULL;
Singleton::Singleton()
{
}
Singleton * Singleton::getInstance()
{
if (instance == NULL) {
instance = new Singleton();
}
return instance;
}测试 main.cpp :
//
// main.cpp
// Pattern
//
// Created by hejinlai on 13-8-6.
// Copyright (c) 2013年 yunzhisheng. All rights reserved.
//
#include <iostream>
#include "Singleton.h"
using namespace std;
int main(int argc, const char * argv[])
{
Singleton * singleton = Singleton::getInstance();
cout << singleton << endl;
Singleton * singleton2 = Singleton::getInstance();
cout << singleton2 << endl;
return 0;
}测试结果：
0x1001000e0
0x1001000e0
三、objective-c 版
单例类 Singleton.h Singleton.m :
// // Singleton.h // ObcPattern // // Created by hejinlai on 13-8-6. // Copyright (c) 2013年 yunzhisheng. All rights reserved. // #import <Foundation/Foundation.h> @interface Singleton : NSObject +(Singleton *)getInstance; @end
//
// Singleton.m
// ObcPattern
//
// Created by hejinlai on 13-8-6.
// Copyright (c) 2013年 yunzhisheng. All rights reserved.
//
#import "Singleton.h"
static Singleton *instance = nil;
@implementation Singleton
+(Singleton *)getInstance
{
if (instance == nil) {
instance = [[self alloc] init];
}
return instance;
}
@end测试 main.m :
//
// main.m
// ObcPattern
//
// Created by hejinlai on 13-8-6.
// Copyright (c) 2013年 yunzhisheng. All rights reserved.
//
#import <Foundation/Foundation.h>
#import "Singleton.h"
int main(int argc, const char * argv[])
{
@autoreleasepool {
Singleton *singleton = [Singleton getInstance];
NSLog(@"%@", singleton);
Singleton *singleton2 = [Singleton getInstance];
NSLog(@"%@", singleton2);
}
return 0;
}测试结果：
2013-08-06 19:43:16.073 ObcPattern[8094:303] <Singleton: 0x1001098b0>
2013-08-06 19:43:16.075 ObcPattern[8094:303] <Singleton: 0x1001098b0>
