OC异常处理

Person.h:

#import <Foundation/Foundation.h>
#import <Foundation/NSObject.h>

@interface Cup : NSObject
{
    int level;   //成员变量-睡的深度值
}
-(int)level;   //获取水的深度
-(void)setLevel:(int)i;   //设置水的深度值
-(void)fill;   //水的深度值增加10
-(void)empty;   //水的深度值减少10
-(void)print;  //输出水的深度值
-(double)set:(double)a over:(double)b;  //计算一个百分比
@end

Person.m:

#import "Person.h"
#import "CupOverflowException.h"
#import "CupWarningException.h"



@implementation Cup:NSObject;
-(id)init  //初始化函数
{
    self = [super init];
    if(self)
    {
        [self setLevel:0];   //初始化水的深度值为0
    }
    return self;
}
-(int)level    //获取水的深度值
{
    return level;
}
-(double)set:(double)_a over:(double)_b  //计算一个百分比
{
    return _a/_b;
}
-(void)setLevel:(int)i
{
    level = i;
    if(level>100)
    {
        NSException *e = [CupOverflowException exceptionWithName:@"CupOverflowException" reason:@"The level is above 100" userInfo:nil];
        @throw e;
    }
    else if(level>=50)
    {
        NSException *e = [CupWarningException exceptionWithName:@"CupWarningException" reason:@"The level is above or at 50" userInfo:nil];
        @throw e;  //抛出警告异常
    }
    else if(level<0)
    {
        NSException *e = [NSException exceptionWithName:@"CupunderflowException" reason:@"The level is blow 0" userInfo:nil];
        @throw e;  //抛出异常
    }
}
-(void)fill   //设置水杯的水的深度值增加10
{
    [self setLevel:level+10];
}
-(void)empty  //设置水杯的水的深度减少10
{
    [self setLevel:level-10];
}
-(void)print  //输出水杯内水的深度值
{
    NSLog(@"Cup level is:%d",level);
}
@end

其他还有两个空类：CupWarningException;CupoverflowException

main:

#import <Foundation/Foundation.h>
#import "Person.h"
#import "CupOverflowException.h"
#import "CupWarningException.h"
#import <Foundation/NSException.h>
#import <Foundation/NSString.h>
#import <Foundation/NSAutoreleasePool.h>


int main(int argc, const char * argv[])
{
    //创建一个自动释放池
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc]init];
    //分配并初始化一个水杯对象
    Cup *cup = [[Cup alloc]init];
    int i;
    for(i=0;i<4;i++)
    {
        [cup fill];
        [cup print];
    }
    for (i=0;i<7;i++) {
        @try {
            [cup fill];
        }
        @catch (CupWarningException *e) {
            NSLog(@"%@ %@",[e name],[e reason]);   //输出警告异常信息
        }
        @catch (CupOverflowException *e) {
            NSLog(@"%@ %@",[e name],[e reason]);   //输出溢出异常信息
        }
        @finally {
            [cup print];
        }
    }
    @try {
        [cup setLevel:-1];
    }
    @catch (NSException *e) {
        NSLog(@"%@ %@",[e name],[e reason]);   //输出深度小于0的异常信息
    }
    [pool release];
    [cup release];
}

结果：

CupWarningException The level is above or at 50

2013-07-31 15:53:32.053 testOC[4063:303] Cup level is:50

2013-07-31 15:53:32.053 testOC[4063:303] CupWarningException The level is above or at 50

2013-07-31 15:53:32.053 testOC[4063:303] Cup level is:60

2013-07-31 15:53:32.054 testOC[4063:303] CupWarningException The level is above or at 50

2013-07-31 15:53:32.054 testOC[4063:303] Cup level is:70

2013-07-31 15:53:32.054 testOC[4063:303] CupWarningException The level is above or at 50

2013-07-31 15:53:32.055 testOC[4063:303] Cup level is:80

2013-07-31 15:53:32.055 testOC[4063:303] CupWarningException The level is above or at 50

2013-07-31 15:53:32.055 testOC[4063:303] Cup level is:90

2013-07-31 15:53:32.056 testOC[4063:303] CupWarningException The level is above or at 50

2013-07-31 15:53:32.056 testOC[4063:303] Cup level is:100

2013-07-31 15:53:32.056 testOC[4063:303] CupOverflowException The level is above 100

2013-07-31 15:53:32.089 testOC[4063:303] Cup level is:110

2013-07-31 15:53:32.090 testOC[4063:303] CupunderflowException The level is blow 0