ios USURL用法注意事项

    NSURL *baseURL = [NSURL URLWithString:@"http://example.com/v1/"];

    [NSURL URLWithString:@"foo" relativeToURL:baseURL];                  // http://example.com/v1/foo

    [NSURL URLWithString:@"foo?bar=baz" relativeToURL:baseURL];          // http://example.com/v1/foo?bar=baz

    [NSURL URLWithString:@"/foo" relativeToURL:baseURL];                 // http://example.com/foo

    [NSURL URLWithString:@"foo/" relativeToURL:baseURL];                 // http://example.com/v1/foo

    [NSURL URLWithString:@"/foo/" relativeToURL:baseURL];                // http://example.com/foo/

    [NSURL URLWithString:@"http://example2.com/" relativeToURL:baseURL]; // http://example2.com/