关于下载的五种方式

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2024-07-17 20:16:09 213人阅读

---恢复内容开始---

#import "ViewController.h"

#import "Campusbeaut.h"

@interface ViewController ()< NSURLConnectionDataDelegate>

{

NSMutableData *_totalData;

NSFileHandle *_fileHandle;

long long _totalLength;

UIImageView *_image;

NSData *_data;

}

@end

@implementation ViewController

- (void)viewDidLoad {

[super viewDidLoad];

_totalData = http://www.mamicode.com/[NSMutableData data]; //相当创建一个可变data

_image=[[UIImageView alloc]initWithFrame:self.view.bounds];

UITapGestureRecognizer *tap=[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(beaut)];

[self.view addGestureRecognizer:tap];

NSError *error;

//用它来创建一个文件

NSFileManager *fileManager = [NSFileManager defaultManager];

[fileManager createFileAtPath:@"/Users/apple/Desktop/campus.jpg" contents:nil attributes:nil];

//也可以用它来创建一个文件夹

[@"" writeToFile:@"/Users/apple/Desktop/test2.db" atomically:YES encoding:NSUTF8StringEncoding error:nil];

//用它来装数据它不能创建文件

_fileHandle = [NSFileHandle fileHandleForWritingAtPath:@"/Users/apple/Desktop/campus.jpg"];

// 方法一

//下载到str

NSURL *url=[NSURL URLWithString:@"http://www.baidu.com"];

NSString *str=[NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:&error];

// NSLog(@"%@",str);

//写到文件中

NSString *path=@"/Users/apple/Desktop/test.db";

[str writeToFile:path atomically:YES encoding:NSUTF8StringEncoding error:&error];

//把文件中的东西读取

NSData *data1=[NSData dataWithContentsOfFile:path];

//再把data 装化为string 当然可以直接读取给string

NSString *str1=[[NSString alloc]initWithData:data1 encoding:NSUTF8StringEncoding ];

// NSLog(@"--------%@",str1);

//方法二

//把图片下载到data

_data =http://www.mamicode.com/[NSData dataWithContentsOfURL:[NSURL URLWithString:@"http://f.hiphotos.baidu.com/image/w%3D310/sign=b6af04fe0b23dd542173a169e108b3df/c9fcc3cec3fdfc03eff99b22d63f8794a5c226a2.jpg"]];

//让图片显示出来

_image.image=[UIImage imageWithData:_data];

[self.view addSubview:_image];

//把图片装在文件中

[_data writeToFile:@"/Users/apple/Desktop/camp.jpg" atomically:YES];

//方法三

//同步方法

NSURL *url1=[NSURL URLWithString:@"http://chzich.diandian.com/post/2014-06-11/40061950061"];

//获取开始下载时间对应俩个结束时间

CFAbsoluteTime begin=CFAbsoluteTimeGetCurrent();//第一种

NSDate *beginDate=[NSDate date];//第二种

//将路径告知请求者

NSURLRequest *request=[NSURLRequest requestWithURL:url1];

//创建响应

NSURLResponse *response;

//使用同步方法

NSData *data2=[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];

//http响应

NSHTTPURLResponse *httpResponse=(NSHTTPURLResponse *)response;//强制类型转化

//打印响应状态

NSLog(@"status code:%d",[httpResponse statusCode]);

if ([httpResponse statusCode] == 200)

{

NSLog(@"成功下载数据");

}

//同步下载时间用的第一种方法

CFAbsoluteTime end = CFAbsoluteTimeGetCurrent();

NSLog(@"%f", end - begin);

//转化成字符串打印出来

NSString *str2=[[NSString alloc]initWithData:data2 encoding:NSUTF8StringEncoding ];

// NSLog(@"++++++++%@",str2);

//方法四

//异步貌似没同步复杂

[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError)

{

NSLog(@"下载完成........");

//这个data参数就是下载数据所处地方

NSString *str3=[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];

// NSLog(@"========%@",str3);

NSLog(@"完成");

}];

NSLog(@"快到碗里来");

//从同步下载开始到异步下载结束所用时间可调整开始位置的放置取得想要的时间使用的是第二种方法从下载时间可以实现优化程序

NSDate *endDate=[NSDate date];

NSLog(@"%f", [endDate timeIntervalSinceDate:beginDate]);

//方法五

//它的机制也是同步的？不过需要使用协议

NSURL *url2=[NSURL URLWithString:@"http://d.hiphotos.baidu.com/image/pic/item/5ab5c9ea15ce36d3de97fa9538f33a87e850b187.jpg"];

NSURLRequest *request1=[NSURLRequest requestWithURL:url2];

NSURLConnection *connection=[[NSURLConnection alloc]initWithRequest:request1 delegate:self];

[connection start];

}

-(void)beaut

{

//_data=http://www.mamicode.com/[NSData dataWithContentsOfFile:@"/Users/apple/Desktop/campus.jpg"];

Campusbeaut *nvnv=[[Campusbeaut alloc]init];

nvnv.Pdata=http://www.mamicode.com/self;//传值

[self presentViewController:nvnv animated:YES completion:nil ];

}

- (void)didReceiveMemoryWarning {

[super didReceiveMemoryWarning];

// Dispose of any resources that can be recreated.

}

#pragma mark - NSURLConnectionDataDelegate

//4. 只有出错才会到这里

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error

{

NSLog(@"Failed: %@", error);

}

//1. 先接受到响应信息，能够知道等下接受的数据是什么样的

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response

{

//如果是多目标下载可以通过参数connection 来判断下载来自哪个请求

NSLog(@"Total length: %lld", [response expectedContentLength]); //网页不是正常的文件长度可能出人意料

_totalLength = response.expectedContentLength;

}

//2. 分次接受数据

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data

{

[_totalData appendData:data];

[_fileHandle writeData:data]; //它们俩都可以来装图片data数据

float progress=(float)[_fileHandle offsetInFile]/_totalLength;

NSLog(@"Data: %.2f%%", progress * 100);

_data3=_totalData;

}

//3. 下载完成

- (void)connectionDidFinishLoading:(NSURLConnection *)connection

{

NSLog(@"finished...");

}

@end

---恢复内容结束---

#import "ViewController.h"

#import "Campusbeaut.h"

@interface ViewController ()< NSURLConnectionDataDelegate>

{

NSMutableData *_totalData;

NSFileHandle *_fileHandle;

long long _totalLength;

UIImageView *_image;

NSData *_data;

}

@end

@implementation ViewController

- (void)viewDidLoad {

[super viewDidLoad];

_totalData = http://www.mamicode.com/[NSMutableData data]; //相当创建一个可变data

_image=[[UIImageView alloc]initWithFrame:self.view.bounds];

UITapGestureRecognizer *tap=[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(beaut)];

[self.view addGestureRecognizer:tap];

NSError *error;

//用它来创建一个文件

NSFileManager *fileManager = [NSFileManager defaultManager];

[fileManager createFileAtPath:@"/Users/apple/Desktop/campus.jpg" contents:nil attributes:nil];

//也可以用它来创建一个文件夹

[@"" writeToFile:@"/Users/apple/Desktop/test2.db" atomically:YES encoding:NSUTF8StringEncoding error:nil];

//用它来装数据它不能创建文件

_fileHandle = [NSFileHandle fileHandleForWritingAtPath:@"/Users/apple/Desktop/campus.jpg"];

// 方法一

//下载到str

NSURL *url=[NSURL URLWithString:@"http://www.baidu.com"];

NSString *str=[NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:&error];

// NSLog(@"%@",str);

//写到文件中

NSString *path=@"/Users/apple/Desktop/test.db";

[str writeToFile:path atomically:YES encoding:NSUTF8StringEncoding error:&error];

//把文件中的东西读取

NSData *data1=[NSData dataWithContentsOfFile:path];

//再把data 装化为string 当然可以直接读取给string

NSString *str1=[[NSString alloc]initWithData:data1 encoding:NSUTF8StringEncoding ];

// NSLog(@"--------%@",str1);

//方法二

//把图片下载到data

//让图片显示出来

_image.image=[UIImage imageWithData:_data];

[self.view addSubview:_image];

//把图片装在文件中

[_data writeToFile:@"/Users/apple/Desktop/camp.jpg" atomically:YES];

//方法三

//同步方法

NSURL *url1=[NSURL URLWithString:@"http://chzich.diandian.com/post/2014-06-11/40061950061"];

//获取开始下载时间对应俩个结束时间

CFAbsoluteTime begin=CFAbsoluteTimeGetCurrent();//第一种

NSDate *beginDate=[NSDate date];//第二种

//将路径告知请求者

NSURLRequest *request=[NSURLRequest requestWithURL:url1];

//创建响应

NSURLResponse *response;

//使用同步方法

NSData *data2=[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];

//http响应

NSHTTPURLResponse *httpResponse=(NSHTTPURLResponse *)response;//强制类型转化

//打印响应状态

NSLog(@"status code:%d",[httpResponse statusCode]);

if ([httpResponse statusCode] == 200)

{

NSLog(@"成功下载数据");

}

//同步下载时间用的第一种方法

CFAbsoluteTime end = CFAbsoluteTimeGetCurrent();

NSLog(@"%f", end - begin);

//转化成字符串打印出来

NSString *str2=[[NSString alloc]initWithData:data2 encoding:NSUTF8StringEncoding ];

// NSLog(@"++++++++%@",str2);

//方法四

//异步貌似没同步复杂

[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError)

{

NSLog(@"下载完成........");

//这个data参数就是下载数据所处地方

NSString *str3=[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];

// NSLog(@"========%@",str3);

NSLog(@"完成");

}];

NSLog(@"快到碗里来");

//从同步下载开始到异步下载结束所用时间可调整开始位置的放置取得想要的时间使用的是第二种方法从下载时间可以实现优化程序

NSDate *endDate=[NSDate date];

NSLog(@"%f", [endDate timeIntervalSinceDate:beginDate]);

//方法五

//它的机制也是同步的？不过需要使用协议

NSURL *url2=[NSURL URLWithString:@"http://d.hiphotos.baidu.com/image/pic/item/5ab5c9ea15ce36d3de97fa9538f33a87e850b187.jpg"];

NSURLRequest *request1=[NSURLRequest requestWithURL:url2];

NSURLConnection *connection=[[NSURLConnection alloc]initWithRequest:request1 delegate:self];

[connection start];

}

-(void)beaut

{

//_data=http://www.mamicode.com/[NSData dataWithContentsOfFile:@"/Users/apple/Desktop/campus.jpg"];

Campusbeaut *nvnv=[[Campusbeaut alloc]init];

nvnv.Pdata=http://www.mamicode.com/self;//传值

[self presentViewController:nvnv animated:YES completion:nil ];

}

- (void)didReceiveMemoryWarning {

[super didReceiveMemoryWarning];

// Dispose of any resources that can be recreated.

}

#pragma mark - NSURLConnectionDataDelegate

//4. 只有出错才会到这里

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error

{

NSLog(@"Failed: %@", error);

}

//1. 先接受到响应信息，能够知道等下接受的数据是什么样的

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response

{

//如果是多目标下载可以通过参数connection 来判断下载来自哪个请求

NSLog(@"Total length: %lld", [response expectedContentLength]); //网页不是正常的文件长度可能出人意料

_totalLength = response.expectedContentLength;

}

//2. 分次接受数据

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data

{

[_totalData appendData:data];

[_fileHandle writeData:data]; //它们俩都可以来装图片data数据

float progress=(float)[_fileHandle offsetInFile]/_totalLength;

NSLog(@"Data: %.2f%%", progress * 100);

_data3=_totalData;

}

//3. 下载完成

- (void)connectionDidFinishLoading:(NSURLConnection *)connection

{

NSLog(@"finished...");

}

@end

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