ios开发网络篇—Get请求和Post请求 - 转

简单说明：建议提交用户的隐私数据一定要使用post请求 
相对post请求而言，get请求的所有参数都直接暴露在url中，请求的url一般会记录在服务器的访问日志中，而服务器的访问日志是黑客攻击的重点对象之一 
用户的隐私数据如登录密码，银行帐号等

示例代码

#define current_screen_width     [uiscreen mainscreen].bounds.size.width
#define current_screen_height     ([uiscreen mainscreen].bounds.size.height - 64)
#define button_width     80
#define button_height    40

@interface viewcontroller ()
//get 请求
@property(nonatomic,strong) uibutton *getbutton;
//post 请求
@property(nonatomic,strong) uibutton *postbutton;
@end

@implementation viewcontroller

- (void)viewdidload {
    [super viewdidload];
    
    _getbutton = [[uibutton alloc] initwithframe:cgrectmake(current_screen_width/2 - button_width/2,
                                                             current_screen_height/2 - button_height,
                                                             button_width,
                                                             button_height)];
    [_getbutton settitle:@"get 请求" forstate:uicontrolstatenormal];
    [_getbutton settitlecolor:[uicolor redcolor] forstate:uicontrolstatenormal];
    [_getbutton addtarget:self
                    action:@selector(getclick)
          forcontrolevents:uicontroleventtouchupinside];
    [self.view addsubview:_getbutton];
    
    _postbutton = [[uibutton alloc] initwithframe:cgrectmake(current_screen_width/2 - button_width/2,
                                                             _getbutton.frame.origin.y + _getbutton.frame.size.height + 60,
                                                             button_width,
                                                             button_height)];
    [_postbutton settitle:@"post 请求" forstate:uicontrolstatenormal];
    [_postbutton settitlecolor:[uicolor redcolor] forstate:uicontrolstatenormal];
    [_postbutton addtarget:self
                    action:@selector(postclick)
          forcontrolevents:uicontroleventtouchupinside];
    [self.view addsubview:_postbutton];
}

/* get 请求 */
-(void)getclick{
    //请求 url
    nsstring* urlstr = [nsstring stringwithformat:@"https://m.che168.com/beijing/?pvareaid=%d",110100];
    //封装成 nsurl
    nsurl* url = [nsurl urlwithstring:urlstr];

    //初始化 请求对象
    nsurlrequest* request = [[nsurlrequest alloc] initwithurl:url];
    //也可以这样初始化对象
    //nsurlrequest* request = [nsurlrequest requestwithurl:url];
    
    //发送请求  默认为 get 请求
    //1 、获得会话对象
    nsurlsession *session = [nsurlsession sharedsession];
    // 2、第一个参数：请求对象
    //      第二个参数：completionhandler回调（请求完成【成功|失败】的回调）
    //      data：响应体信息（期望的数据）
    //      response：响应头信息，主要是对服务器端的描述
    //      error：错误信息，如果请求失败，则error有值
    nsurlsessiondatatask *datatask = [session datataskwithrequest:request completionhandler:^(nsdata * _nullable data, nsurlresponse * _nullable response, nserror * _nullable error) {
        if(!error){
            nslog(@"请求加载成功。。。");
            //说明：（此处返回的数据是json格式的，因此使用nsjsonserialization进行反序列化处理）
            // nsdictionary *dict = [nsjsonserialization jsonobjectwithdata:data options:kniloptions error:nil];
            //如果是字符串则直接取出
            nsstring *str = [[nsstring alloc] initwithdata:data encoding:nsutf8stringencoding];
            nslog(@"get 请求返回的结果是：%@",[str substringtoindex: 300]);
        }
    }];
    //执行任务
    [datatask resume];
    
    /* ------------ ios9 之前请求方法，之后改成 nsurlsession 请求  --------------
    [nsurlconnection sendasynchronousrequest:request queue:[nsoperationqueue mainqueue] completionhandler:^(nsurlresponse * _nullable response, nsdata * _nullable data, nserror * _nullable connectionerror) {
        if(!connectionerror){
            nslog(@"加载成功。。。");
            nsstring *str = [[nsstring alloc] initwithdata:data encoding:nsutf8stringencoding];
            nslog(@"加载的内容是：%@",[str substringtoindex:200]);
        }else{
            nslog(@"加载失败");
        }
    }];
    */
}


/* post 请求 */
-(void)postclick{
    nsstring *urlstr = [nsstring stringwithformat:@"https://m.che168.com/"];
    //转码
    // stringbyaddingpercentescapesusingencoding 只对 `#%^{}[]|\"<> 加空格共14个字符编码，不包括”&?”等符号), ios9将淘汰
    // ios9 以后要换成 stringbyaddingpercentencodingwithallowedcharacters 这个方法进行转码
    urlstr = [urlstr stringbyaddingpercentencodingwithallowedcharacters:[[nscharacterset charactersetwithcharactersinstring:@"?!@#$^&%*+,:;='\"`<>()[]{}/\\| "] invertedset]];
    nsurl *url = [nsurl urlwithstring:urlstr];
    
    //创建会话对象
    nsurlsession *session = [nsurlsession sharedsession];
    
    //创建请求对象
    nsmutableurlrequest *request =[[nsmutableurlrequest alloc] initwithurl:url];
    [request sethttpmethod:@"post"];
    [request sethttpbody:[@"a=1&b=2&c=3&type=json" datausingencoding:nsutf8stringencoding]];
    
    //根据会话对象创建一个 task（发送请求）
    nsurlsessiondatatask* datatask = [session datataskwithrequest:request completionhandler:^(nsdata * _nullable data, nsurlresponse * _nullable response, nserror * _nullable error) {
        if(!error){
            //8.解析数据
            // nsdictionary *dict = [nsjsonserialization jsonobjectwithdata:data options:kniloptions error:nil];
            // nslog(@"%@",dict);
            nsstring *str = [[nsstring alloc] initwithdata:data encoding:nsutf8stringencoding];
            nslog(@"post 加载的内容是：%@",[str substringtoindex:200]);
        }else{
            nslog(@"请求发生错误：%@", [error description]);
        }
    }];
    [datatask resume]; //执行任务
}