大家都知道ASIHTTPRequest系列的类很好用，功能很强大。但也像NSURLConnection一样，一个网络请求就需要实例化一个对象，而且无法避免重复请求的问题。
我个人不习惯用ASIHTTPRequest，因为它功能太强大了，函数太多了，而我们平时的项目仅仅是处理基于HTTP协议的网络交互，用ASIHTTPRequest未免太“奢侈”了。更重要的是，它并无法避免网络的重复请求的问题，而且无法控制网络请求数量，所以仅仅使用ASIHTTPRequest还不够。
事实上，用NSURLConnection足够了。下面是我写的封装
HTTPConnection.h
//
// HTTPConnection.h
//
//
// Created by Jianhong Yang on 12-1-3.
// Copyright (c) 2012年 __MyCompanyName__. All rights reserved.
//
#import <Foundation/Foundation.h>
@protocol HTTPConnectionDelegate;
@interface HTTPConnection : NSObject {
@private
//
int _numberOfURLConnection;
int _maxNumberOfURLConnection;
NSMutableArray *_marrayTaskDic;
id <HTTPConnectionDelegate> _delegate;
}
@property (nonatomic, assign) int maxNumberOfURLConnection;
@property (nonatomic, assign) id <HTTPConnectionDelegate> delegate;
// 根据URL获取Web数据
- (BOOL)requestWebDataWithURL:(NSString *)strURL andParam:(NSDictionary *)dicParam priority:(BOOL)priority;
// 根据URLRequest获取Web数据
- (BOOL)requestWebDataWithRequest:(NSURLRequest *)request andParam:(NSDictionary *)dicParam priority:(BOOL)priority;
//取消网络请求
- (BOOL)cancelRequest:(NSDictionary *)dicParam;
//清空网络请求
- (void)clearRequest;
@end
@protocol HTTPConnectionDelegate <NSObject>
@optional
// 网络数据下载失败
- (void)httpConnect:(HTTPConnection *)httpConnect error:(NSError *)error with:(NSDictionary *)dicParam;
// 服务器返回的HTTP信息头
- (void)httpConnect:(HTTPConnection *)httpConnect receiveResponseWithStatusCode:(NSInteger)statusCode
andAllHeaderFields:(NSDictionary *)dicAllHeaderFields with:(NSDictionary *)dicParam;
// 服务器返回的部分数据
- (void)httpConnect:(HTTPConnection *)httpConnect receiveData:(NSData *)data with:(NSDictionary *)dicParam;
// 网络数据下载完成
- (void)httpConnect:(HTTPConnection *)httpConnect finish:(NSData *)data with:(NSDictionary *)dicParam;
@end
#ifdef DEBUG
#define HTTPLOG(fmt,...) NSLog((@"HTTP->%s(%d):"fmt),__PRETTY_FUNCTION__,__LINE__,##__VA_ARGS__)
#else
#define HTTPLOG(fmt,...) NSLog(fmt,##__VA_ARGS__)
#endif
HTTPConnection.m
//
// HTTPConnection.m
//
//
// Created by Jianhong Yang on 12-1-3.
// Copyright (c) 2012年 __MyCompanyName__. All rights reserved.
//
#import "HTTPConnection.h"
#define MAXNUMBER_URLCONNECTION 10
#define TASKSTATUS_RUN @"Run"
#define TASKSTATUS_WAIT @"Wait"
@interface HTTPConnection (Private)
- (void)startURLConnection;
@end
@implementation HTTPConnection
@synthesize maxNumberOfURLConnection = _maxNumberOfURLConnection;
@synthesize delegate = _delegate;
- (id)init
{
self = [super init];
if (self) {
// Custom initialization.
_numberOfURLConnection = 0;
_maxNumberOfURLConnection = MAXNUMBER_URLCONNECTION;
_marrayTaskDic = [[NSMutableArray alloc] initWithCapacity:5];
}
return self;
}
- (void)dealloc
{
//清空任务
[self clearRequest];
//
[_marrayTaskDic release];
[super dealloc];
}
#pragma mark -
#pragma mark Public
// 根据URL获取Web数据
- (BOOL)requestWebDataWithURL:(NSString *)strURL andParam:(NSDictionary *)dicParam priority:(BOOL)priority
{
if (nil == dicParam) {
return NO;
}
NSURL *url = [NSURL URLWithString:strURL];
NSURLRequest *request = [[NSURLRequest alloc] initWithURL:url];
BOOL success = [self requestWebDataWithRequest:request andParam:dicParam priority:priority];
[request release];
return success;
}
// 根据URLRequest获取Web数据
- (BOOL)requestWebDataWithRequest:(NSURLRequest *)request andParam:(NSDictionary *)dicParam priority:(BOOL)priority
{
if (nil == dicParam) {
return NO;
}
//正在处理或等待处理的任务不再接收
for (NSDictionary *dicTask in _marrayTaskDic) {
//
if ([dicParam isEqualToDictionary:[dicTask objectForKey:@"param"]]) {
HTTPLOG(@"任务重复:%@", dicParam);
//需优先处理且为等待状态
if (priority && [[dicParam objectForKey:@"status"] isEqualToString:TASKSTATUS_WAIT]) {
[dicTask retain];
[_marrayTaskDic removeObject:dicTask];
[_marrayTaskDic insertObject:dicTask atIndex:0];
[dicTask release];
}
return NO;
}
}
HTTPLOG(@"添加新任务，参数:%@", dicParam);
NSMutableDictionary *mdicTask = [[NSMutableDictionary alloc] initWithCapacity:3];
//设置数据缓存
NSMutableData *mdataCache = [[NSMutableData alloc] init];
[mdicTask setObject:mdataCache forKey:@"cache"];
[mdataCache release];
//参数
[mdicTask setObject:dicParam forKey:@"param"];
//状态
[mdicTask setObject:TASKSTATUS_WAIT forKey:@"status"];
//创建HTTP网络连接
NSURLConnection *urlConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO];
[mdicTask setObject:urlConnection forKey:@"connect"];
[urlConnection release];
//保存到数组
if (priority) {
[_marrayTaskDic insertObject:mdicTask atIndex:0];
}
else {
[_marrayTaskDic addObject:mdicTask];
}
[mdicTask release];
[self startURLConnection];
return YES;
}
// 取消网络请求
- (BOOL)cancelRequest:(NSDictionary *)dicParam
{
if (nil == dicParam) {
return NO;
}
//遍历所有任务
for (int i = 0; i < _marrayTaskDic.count; i++) {
//查看任务是否相同
NSDictionary *dicTask = [_marrayTaskDic objectAtIndex:i];
if ([dicParam isEqualToDictionary:[dicTask objectForKey:@"param"]]) {
//取消网络请求
NSURLConnection *connect = [dicTask objectForKey:@"connect"];
//未启动的须先启动再取消，不然有内存泄露
if ([TASKSTATUS_WAIT isEqualToString:[dicTask objectForKey:@"status"]]) {
[connect start];
}
[connect cancel];
//从任务队列中删除
[_marrayTaskDic removeObjectAtIndex:i];
_numberOfURLConnection -= 1;
return YES;
}
}
return NO;
}
// 清空网络请求
- (void)clearRequest
{
//遍历所有任务
for (NSDictionary *dicTask in _marrayTaskDic) {
NSURLConnection *connect = [dicTask objectForKey:@"connect"];
//未启动的须先启动再取消，不然有内存泄露
if ([TASKSTATUS_WAIT isEqualToString:[dicTask objectForKey:@"status"]]) {
[connect start];
}
[connect cancel];
//
_numberOfURLConnection -= 1;
}
//从任务队列中删除
[_marrayTaskDic removeAllObjects];
}
// 获取已经下载到的数据
- (void)loadReceivedDataOf:(NSDictionary *)dicParam into:(NSMutableData *)mdataReceived
{
for (NSDictionary *dicTask in _marrayTaskDic) {
//找到相应的数据
if ([dicParam isEqualToDictionary:[dicTask objectForKey:@"param"]]) {
//取出已经下载到的数据
NSData *data = [dicTask objectForKey:@"cache"];
if (data.length > 0) {
[mdataReceived setData:data];
break;
}
}
}
}
#pragma mark -
#pragma mark NSURLConnectionDataDelegate
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
HTTPLOG(@"网络请求错误:%@", error);
//找到当前失败的任务
int indexTask = 0;
NSDictionary *dicTask = nil;
for (int i = 0; i < _marrayTaskDic.count; i++) {
NSDictionary *dic = [_marrayTaskDic objectAtIndex:i];
//找到网络连接相应的数据字典
if ([dic objectForKey:@"connect"] == connection) {
indexTask = i;
dicTask = [dic retain];
break;
}
}
//删除失败的任务
if (dicTask) {
//删除
_numberOfURLConnection -= 1;
[_marrayTaskDic removeObjectAtIndex:indexTask];
//启动新任务
[self startURLConnection];
//通知上层任务失败
NSDictionary *dicParam = [dicTask objectForKey:@"param"];
if ([_delegate respondsToSelector:@selector(httpConnect:error:with:)]) {
[_delegate httpConnect:self error:error with:dicParam];
}
}
[dicTask release];
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
HTTPLOG(@"网络请求收到响应");
//找到相应的任务
NSDictionary *dicTask = nil;
for (int i = 0; i < _marrayTaskDic.count; i++) {
NSDictionary *dic = [_marrayTaskDic objectAtIndex:i];
//找到网络连接相应的数据字典
if ([dic objectForKey:@"connect"] == connection) {
dicTask = dic;
break;
}
}
//
if ([response isMemberOfClass:NSHTTPURLResponse.class]) {
NSHTTPURLResponse *responseHTTP = (NSHTTPURLResponse *)response;
NSUInteger statusCode = responseHTTP.statusCode;
NSDictionary *dicAllHeaderFields = responseHTTP.allHeaderFields;
NSDictionary *dicParam = [dicTask objectForKey:@"param"];
//收到服务器返回的HTTP信息头
SEL receiveResponse = @selector(httpConnect:receiveResponseWithStatusCode:andAllHeaderFields:with:);
if ([self.delegate respondsToSelector:receiveResponse]) {
[self.delegate httpConnect:self receiveResponseWithStatusCode:statusCode
andAllHeaderFields:dicAllHeaderFields with:dicParam];
}
}
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
HTTPLOG(@"网络请求收到数据");
//找到相应的任务
NSDictionary *dicTask = nil;
for (int i = 0; i < _marrayTaskDic.count; i++) {
NSDictionary *dic = [_marrayTaskDic objectAtIndex:i];
//找到网络连接相应的数据字典
if ([dic objectForKey:@"connect"] == connection) {
dicTask = dic;
break;
}
}
//
if (dicTask) {
//向缓存中添加数据
NSMutableData *mdataCache = [dicTask objectForKey:@"cache"];
[mdataCache appendData:data];
NSDictionary *dicParam = [dicTask objectForKey:@"param"];
HTTPLOG(@"该数据的参数：%@", dicParam);
//收到部分数据
if ([self.delegate respondsToSelector:@selector(httpConnect:receiveProgressChanged:with:)]) {
[self.delegate httpConnect:self receiveProgressChanged:mdataCache.length with:dicParam];
}
}
HTTPLOG(@"网络请求收到数据并处理完成");
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
HTTPLOG(@"网络请求完成");
//找到当前完成的任务
int indexTask = 0;
NSDictionary *dicTask = nil;
for (int i = 0; i < _marrayTaskDic.count; i++) {
NSDictionary *dic = [_marrayTaskDic objectAtIndex:i];
//找到网络连接相应的数据字典
if ([dic objectForKey:@"connect"] == connection) {
indexTask = i;
dicTask = [dic retain];
break;
}
}
//删除已经完成的任务
if (dicTask) {
//删除
_numberOfURLConnection -= 1;
[_marrayTaskDic removeObjectAtIndex:indexTask];
//启动新任务
[self startURLConnection];
//通知上层完成任务
NSData *dataCache = [dicTask objectForKey:@"cache"];
NSDictionary *dicParam = [dicTask objectForKey:@"param"];
if ([_delegate respondsToSelector:@selector(httpConnect:finish:with:)]) {
[_delegate httpConnect:self finish:dataCache with:dicParam];
}
}
[dicTask release];
}
#pragma mark - Private
- (void)startURLConnection
{
if (_numberOfURLConnection < _maxNumberOfURLConnection) {
if (_numberOfURLConnection < _marrayTaskDic.count) {
//找到等待状态的任务
for (NSMutableDictionary *mdicTask in _marrayTaskDic) {
if ([TASKSTATUS_WAIT isEqualToString:[mdicTask objectForKey:@"status"]]) {
//修改状态
[mdicTask setObject:TASKSTATUS_RUN forKey:@"status"];
//启动
NSURLConnection *urlConnection = [mdicTask objectForKey:@"connect"];
[urlConnection start];
break;
}
}
//
_numberOfURLConnection += 1;
}
}
HTTPLOG(@"正在处理的网络请求数：%i，等待处理的网络请求：%i",
_numberOfURLConnection, _marrayTaskDic.count-_numberOfURLConnection);
}
@end
这个类有四个接口，后两个是取消网络请求的，不必讨论。前两个是发起网络请求的，用的最多的就是这两个接口了。如果只是通过GET方法从服务器取数据，第一个接口足够了。当然也可以用第二个。如果需要用POST方式向服务器发送数据，得用第二个接口。属性maxNumberOfURLConnection表示同时运行的URL连接数。
第一个接口的第一个参数是URL字符串，第二个参数用来区分网络请求的，如果两次请求的第二个参数一样，第二次请求会被过滤掉。这个参数还有一个作用，就是协议回调函数的参数，用来让上层区分网络请求的。第三个参数表示是否需要优先处理。
第二个接口的第一个参数是NSURLRequest类型，用来设置网络请求参数的，比如POST、要发送的数据流、HTTP信息头等。第二个、第三个参数的作用跟第一个接口的第二个、第三个参数意义一样。
该类对应的协议就不必谈了，大家能看懂的。该类功能的具体实现，大家自己分析。
有什么问题记得联系我O