json的几种转换

 

 +(NSString *) jsonStringWithString:(NSString *) string{

    return [NSString stringWithFormat:@"\"%@\"",

            [[string stringByReplacingOccurrencesOfString:@"\n" withString:@"\\n"] stringByReplacingOccurrencesOfString:@"\""withString:@"\\\""]

            ];

}

+(NSString *) jsonStringWithDictionary:(NSDictionary *)dictionary{

    NSArray *keys = [dictionary allKeys];

    NSMutableString *reString = [NSMutableString string];

    [reString appendString:@"{"];

    NSMutableArray *keyValues = [NSMutableArray array];

    for (int i=0; i<[keys count]; i++) {

        NSString *name = [keys objectAtIndex:i];

        id valueObj = [dictionary objectForKey:name];

        NSString *value = [self jsonStringWithObject:valueObj];

        if (value) {

            [keyValues addObject:[NSString stringWithFormat:@"\"%@\":%@",name,value]];

        }

    }

    [reString appendFormat:@"%@",[keyValues componentsJoinedByString:@","]];

    [reString appendString:@"}"];

    return reString;

}

+(NSString *) jsonStringWithObject:(id) object{

    NSString *value = nil;

    if (!object) {

        return value;

    }

    if ([object isKindOfClass:[NSString class]]) {

        value = [self jsonStringWithString:object];

    }else if([object isKindOfClass:[NSDictionary class]]){

        value = [self jsonStringWithDictionary:object];

    }else if([object isKindOfClass:[NSArray class]]){

        value = [self jsonStringWithArray:object];

    }

    return value;

}

+(NSString *) jsonStringWithArray:(NSArray *)array{

    NSMutableString *reString = [NSMutableString string];

    [reString appendString:@"["];

    NSMutableArray *values = [NSMutableArray array];

    for (id valueObj in array) {

        NSString *value = [self jsonStringWithObject:valueObj];

        if (value) {

            [values addObject:[NSString stringWithFormat:@"%@",value]];

        }

    }

    [reString appendFormat:@"%@",[values componentsJoinedByString:@","]];

    [reString appendString:@"]"];

    return reString;

}

 

 

 具体根据情况使用