UIWebView缓存清理

UIWebView缓存清理的方式

https://stackoverflow.com/questions/2523435/how-to-clear-uiwebview-cache

if (lastReq){
    [[NSURLCache sharedURLCache] removeCachedResponseForRequest:lastReq];
    [[NSURLCache sharedURLCache] removeAllCachedResponses];

}

lastReq=[NSMutableURLRequest requestWithURL:[NSURL URLWithString:localUrl]
                                   cachePolicy:NSURLRequestReloadIgnoringCacheData
                               timeoutInterval:10000];
[lastReq setCachePolicy:NSURLRequestReloadIgnoringLocalCacheData];

[self.mainWebView loadRequest:lastReq];