iOS開發中對于NSURLRequest的封裝

在ios開發中經常用到NSURLRequest類來進行url請求，通常有以下步驟

1.實例化NSURL;

2.實例化NSURLRequest；

3.連接[NSURLConnection connectionWithRequest:request delegate:self];

4.實現NSURLConnectionDataDelegate協議;

這樣的話比較繁瑣，可以對其進行封裝

1.新建一個MyUrlRequest類

MyUrlRequest.h文件

    @interface MyUrlRequest : NSObject <NSURLConnectionDataDelegate> {

        NSMutableData *_mData;//接收數據

    }


@property (nonatomic, copy) NSString *urlStr;  
@property (nonatomic, copy) void (^finishBlock)(NSData *data);//請求成功回調block  
@property (nonatomic, copy) void (^failedBlick)();//請求失敗回調block  
@property (nonatomic, assign) BOOL isCache;//是否緩存  

- (void)startRequest;//開始請求  

@end  </pre> 


 MyUrlRequest.m文件
    #import "MyUrlRequest.h"


#import "NSString+Hashing.h"  

@implementation QFURLRequest  

@synthesize urlStr;  
@synthesize finishBlock;  
@synthesize failedBlick;  
@synthesize isCache;  

- (id)init {  
    if (self = [super init]) {  
        _mData = [[NSMutableData alloc] init];  
    }  
    return self;  
}  

- (void)startRequest {  
    //MyRequestManager里邊autorelease掉，在這里可能出錯，所以需要retain  
    [self retain];  
    if (self.isCache) {  
        //如果有緩存，則使用緩存  
        NSString *path = [NSHomeDirectory() stringByAppendingFormat:@"/tmp/%@", [self.urlStr MD5Hash]];  
        NSFileManager *manager = [NSFileManager defaultManager];  
        if ([manager fileExistsAtPath:path]) {  
            NSData *data = [NSData dataWithContentsOfFile:path];  
            self.finishBlock(data);  
            return;  
        }  
    }  

    NSURL *url = [NSURL URLWithString:self.urlStr];  
    NSURLRequest *request = [NSURLRequest requestWithURL:url];  
    [NSURLConnection connectionWithRequest:request delegate:self];  
}  
//實現NSURLConnectionDataDelegate協議  
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {  
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];  
}  

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {  
    [_mData appendData:data];  
}  

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {  
    [self release];  
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];  
    //寫緩存  
    if (self.isCache) {  
        NSString *path = [NSHomeDirectory() stringByAppendingFormat:@"/tmp/%@", [self.urlStr MD5Hash]];  
        [_mData writeToFile:path atomically:YES];  
    }  

    self.finishBlock(_mData);  
}  

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {  
    [self release];  
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];  
    self.failedBlick();  
}  

- (void)dealloc {  
    [_mData release];  
    self.finishBlock = nil;  
    self.failedBlick = nil;  
    [super dealloc];  
}  

@end  </pre> 


 2.新建一個MyRequestManager類
 .h文件 

    #import <Foundation/Foundation.h>


#import "MyUrlRequest.h"  

@interface MyRequestManager : NSObject  

+ (void)requestWithUrl:(NSString *)urlString andIsCache:(BOOL)isCache finish:(void(^)(NSData *data))finishBlock failed:(void(^)())failedBlock;  

@end  </pre> 


 .m文件
    #import "MyRequestManager.h"


@implementation MyRequestManager  

+ (void)requestWithUrl:(NSString *)urlString andIsCache:(BOOL)isCache finish:(void(^)(NSData *data))finishBlock failed:(void(^)())failedBlock  
{  
    MyUrlRequest *request = [[[MyUrlRequest alloc] init] autorelease];  
    request.urlStr = urlString;  
    request.isCache = isCache;  
    request.finishBlock = finishBlock;  
    request.failedBlick =  failedBlock;  
    //在發送startRequest消息之后，該類方法結束，可能會對request發送autorelease消息，這樣的話在request的startRequest方法中就可能會產生錯誤，所以要在startRequest方法中retain一下  
    [request startRequest];  
}  

@end  </pre> 


 這樣的話，以后再發送請求就可以直接調用
[MyRequestManager requestWithUrl:(NSString *)urlString andIsCache:(BOOL)isCache finish:(void(^)(NSData *data))finishBlock failed:(void(^)())failedBlock ];