一般如果只是 alloc init 那么 用new 是一样的 

SomeObject*myObject =[[SomeObject alloc] init];

SomeObject*myObject =[SomeObjectnew]; 即上述两种情况是一样的！

#import "InitAllocNewTest.h"@implementation InitAllocNewTest+(id)alloc{    NSLog(@"Allocating...");    return [super alloc];}-(id)init{    NSLog(@"Initializing...");    return [super init];}@endIn main function both statements:[[InitAllocNewTest alloc] init];and[InitAllocNewTest new];result in the same output:2013-03-06 16:45:44.125 XMLTest[18370:207] Allocating...2013-03-06 16:45:44.128 XMLTest[18370:207] Initializing...

Some selected ones are:

• new doesn't support custom initializers (like initWithString)
• alloc-init is more explicit than new