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IOS之云端应用(转)

10.1 GET请求

10.2 XML解析

10.3 JSON解析

10.4 POST请求

10.1 GET请求

通过一个第三方提供的云服务,查询IP归属地:http://www.youdao.com/smartresult-xml/search.s?type=ip&q=218.241.121.186

它的返回格式是xml :

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新建个例子:CSSimpleXML,设计原型:

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编辑按钮事件:

- (IBAction)query:(id)sender {    NSString* strUrl = [NSString stringWithFormat:@"http://www.youdao.com/smartresult-xml/search.s?type=ip&q=%@", ipText.text];    NSURL* url = [NSURL URLWithString:strUrl];        NSURLRequest* request = [[NSURLRequest alloc]initWithURL:url];        NSURLConnection* connection = [[NSURLConnection alloc]initWithRequest:request delegate:self];        [connection release];    [request release];    [activityIndicator startAnimating];}

 

定义NSURLConnection的委托:

NSURLRequest *request = [[NSURLRequest alloc] initWithURL:url];

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

委托(delegate)是一种事件处理机制,当满足条件时候触发。delegate:self说明是委托当前对象处理事件,我们需要实现它们回调方法。

 NSURLConnection 回调方法

-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data 请求成功,并且接收数据。-(void) connection:(NSURLConnection *)connection  didFailWithError: (NSError *)error  请求成功,但是加载数据出现异常。-(void) connectionDidFinishLoading: (NSURLConnection*) connection加载数据成功,在connection:didReceiveData方法之后执行。

接收数据处理

-(void)connection:(NSURLConnection*)connection didReceiveData:(NSData *)data {    //默认对于中文的支持不好    NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);    NSString* gbkNSString = [[NSString alloc]initWithData:data encoding:enc];    //如果是黑UTF-8 NSXMLParese会报错    xmlString = [[NSString alloc]initWithString:[gbkNSString stringByReplacingOccurrencesOfString:@"<?xml version=\"1.0\" encoding=\"gbk\"?>" withString:@"<?xml version=\"1.0\" encoding=\"utf-8\"?>"]];    NSLog(@"%@", xmlString);    [gbkNSString release];}

 

iPhone SDK提供的XML解析类只能解析utf-8编码,如果从服务器返回的xml编码是gbk等,要转换成utf-8再开始解析。

10.2 XML解析

关于iPhone发送GET请求,就是通过NSURLRequest和NSURLConnection两个类实现的。

在众多的回调方法。解析XML是在 connectionDidFinishLoading:方法开始的。

解析XML文件也是要通过XML回调方式实现解析处理的。

NSXMLParser,是iPhone解析XML SDK工具类。

NSXMLParser采用SAX方式而不是DOM方式解析,SAX是基于事件触发的解析方式,解析器从上到下遍历xml文档,遇到开始标签、结束标签、文档开始、文档结束和字符串都会触发事件。

 解析开始处理

 

-(void)connectionDidFinishLoading:(NSURLConnection*)connection {    [activityIndicator stopAnimating];    //开始解析XML    NSXMLParser* ipParser = [[NSXMLParser alloc]initWithData:[xmlString dataUsingEncoding:NSUTF8StringEncoding ]];;    ipParser.delegate = self;    [ipParser parse];    [ipParser release];}

 

NSXMLParser回调方法

- (void)parserDidStartDocument:(NSXMLParser *)parser文档开始的时候触发- (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError  文档出错的时候触发- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *) qualifiedName attributes:(NSDictionary *)attributeDict 遇到一个开始标签时候触发。- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string 遇到字符串时候触发- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementNamenamespaceURI:(NSString *)namespaceURIqualifiedName:(NSString *)qName 遇到结束标签时候出发。- (void)parserDidEndDocument:(NSXMLParser *)parser  遇到文档结束时候触发。

文档开始的回调方法

这个方法在解析过程中只调运一次,一般在这个方法中进行有关解析的初始化处理。

//文档开始的时候触发- (void)parserDidStartDocument:(NSXMLParser *)parser {    info = [[NSMutableDictionary alloc]initWithCapacity:1];}

 

文档出错回调方法

//文档出错的时候触发- (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError {    UIAlertView* errorAlert = [[UIAlertView alloc]initWithTitle:[parseError localizedDescription] message:[parseError localizedFailureReason] delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];    [errorAlert show];    [errorAlert release];}

 

遇到开始标签回调方法

参数elementName是标签的名字,attributeDict 是属性列表,namespaceURI 是命名空间,如果有命名空间qualifiedName是指定的前缀名。

//遇到一个开始标签时候触发。- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *) qualifiedName attributes:(NSDictionary *)attributeDict {    NSLog(@"value:%@\n", elementName);    currentTagName = elementName;}

 

遇到字符串回调方法

//遇到字符串时候触发- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string {    NSLog(@"value:%@\n", string);    string = [string stringByReplacingOccurrencesOfString:@"\n" withString:@""];    if ([currentTagName isEqualToString:@"ip"]) {        if (![string isEqualToString:@""]) {            [info setValue:string forKey:currentTagName];        }     } else if([currentTagName isEqualToString:@"location"]) {        if (![string isEqualToString:@""]) {            [info setValue:string forKey:currentTagName];        }    }}

 

遇到结束标签回调方法

//遇到结束标签时候出发。- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementNamenamespaceURI:(NSString *)namespaceURIqualifiedName:(NSString *)qName {}

 

遇到结束文档回调方法

// 遇到文档结束时候触发。- (void)parserDidEndDocument:(NSXMLParser *)parser  {    NSMutableString* outString = [[NSMutableString alloc]initWithCapacity:1];    for (id key in info) {        [outString appendFormat:@"%@:%@\n", key, [info objectForKey:key]];    }    msgText.text = outString;    [outString release];    [xmlString release];}

 

10.3 JSON解析

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http://www.geonames.org/export/ws-overview.html

获得JSON:

{    status =     {        message = "the daily limit of 30000 credits demo has been exceeded.Please throttle your requests or use the commercial service.";        value = http://www.mamicode.com/18;>

10.3.1 JSON解析API

iPhone SDK没有提供JSON解析API,可以使用第三方的API类库json-framework,下载地址:

https://github.com/stig/json-framework/

把Classes/JSON/下面的类拷贝到我们的工程的Classes目录下面,右键添加存在的类文件。

实现回调方法

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data - (void) connectionDidFinishLoading: (NSURLConnection*) connection-(void) connection:(NSURLConnection *)connection  didFailWithError: (NSError *)error 

connection:didReceiveData:

-(void)connection:(NSURLConnection*)connection didReceiveData:(NSData *)data {    outString = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];    NSLog(@"%@", outString);}

 

connectionDidFinishLoading:

outString的 JSONValue消息获得NSMutableDictionary,JSON api中提供了NSString的分类(Catelog)

-(void)connectionDidFinishLoading:(NSURLConnection*)connection {    NSMutableDictionary* jsonObj = [outString JSONValue];    NSLog(@"%@", jsonObj);    NSMutableDictionary* jsonSubObj = [jsonObj objectForKey:@"status"];        NSString* text = [[NSString alloc]initWithFormat:@"message=%@\n\nvalue=http://www.mamicode.com/%@", [jsonSubObj objectForKey:@"message"],[jsonSubObj objectForKey:@"value"]];    mstText.text = text;    [text release];    [outString release];    [activity stopAnimating];}

 

文档出错回调方法

-(void) connection:(NSURLConnection *)connection  didFailWithError: (NSError *)error {    UIAlertView* errorAlert = [[UIAlertView alloc]initWithTitle:[error localizedDescription] message:[error localizedFailureReason] 
                    delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil]; [errorAlert show]; [errorAlert release];}

 

点击按钮事件

-(IBAction)go:(id)sender{    NSString *strurl =@"http://api.geonames.org/findNearByWeatherJSON?lat=43&lng=-2&username=demo";  NSURL *url = [NSURL URLWithString:strurl];  NSURLRequest *request = [[NSURLRequest alloc]initWithURL:url];  NSURLConnection *connection = [[NSURLConnection alloc]initWithRequest:request delegate:self];  [connection release];  [request release];  [activityIndicatorView startAnimating];}

10.4 POST请求

为了学习iPhone的POST请求,安排案例如下:

在画面中输入用户名和密码,然后以POST方式提交数据到服务器端。

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NSMutableURLRequest

POST请求与GET不同,不使用的NSURLRequest,而是使用NSMutableURLRequest类,这是一个可变的NSURLRequest类。

- (IBAction)login:(id)sender {    //http://www.sunnyer.com/shop/member!login.action    //member.email:dfgdrgdg@af.cd    //member.password:dfgdfgrf    [activity startAnimating];    NSString* post = [NSString stringWithFormat:@"memberIdOrCellphoneOrEmail=%@&&password=%@", username.text, password.text];    NSData* postData = http://www.mamicode.com/[post dataUsingEncoding:NSUTF8StringEncoding];"http://www.jinjiang.com/membercenter/member/ordinaryLogin"];    NSMutableURLRequest* request = [NSMutableURLRequest requestWithURL:postServierURL];    [request setHTTPMethod:@"POST"];    [request setHTTPBody:postData];    NSURLConnection* connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];    if (!connection) {        NSLog(@"Failed to submit request");    } else {        NSLog(@"Request submitted");    }    [connection release];}

 

POST参数是以一个字符串方式传递: memberIdOrCellphoneOrEmail=%@&&password=%@

[request setHTTPMethod:@"POST"];

知道请求方法为POST方法,但是要注意POST必须大写。

[request setHTTPBody:postData];该语句是将要提交的数据放到请求体中。

connection:didReceiveData:

-(void)connection:(NSURLConnection*)connection didReceiveData:(NSData *)data {    outString = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];    NSLog(@"%@", outString);}

 

connectionDidFinishLoading:

-(void)connectionDidFinishLoading:(NSURLConnection*)connection{    NSLog(@"%@", outString);    [webView loadHTMLString:outString baseURL:[[NSURL alloc]initWithString:@"http://www.jinjiang.com"]];    [activity stopAnimating];}

 

文档出错回调方法

-(void) connection:(NSURLConnection *)connection  didFailWithError: (NSError *)error {    UIAlertView* errorAlert = [[UIAlertView alloc]initWithTitle:[error localizedDescription] message:[error localizedFailureReason]
                  delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
[errorAlert show];
[errorAlert release];
}