新建Object文件

.h文件中

+(NSString *)convertToJsonData:(NSDictionary *)dict；

.m文件中

+(NSString *)convertToJsonData:(NSDictionary *)dict

{

NSError *error;

NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dict options:NSJSONWritingPrettyPrinted error:&error];

NSString *jsonString;

if (!jsonData) {

NSLog(@"%@",error);

}else{

jsonString = [[NSString alloc]initWithData:jsonData encoding:NSUTF8StringEncoding];

}

NSMutableString *mutStr = [NSMutableString stringWithString:jsonString];

NSRange range = {0,jsonString.length};

//去掉字符串中的空格

[mutStr replaceOccurrencesOfString:@" " withString:@"" options:NSLiteralSearch range:range];

NSRange range2 = {0,mutStr.length};

//去掉字符串中的换行符

[mutStr replaceOccurrencesOfString:@"\n" withString:@"" options:NSLiteralSearch range:range2];

return mutStr;

}

用法：

NSString *datastr = [WXObject convertToJsonData:dict];