IOS开发（74）之把 Array 和 Dictionaries 序列化成 JSON 对象

1 前言
通过 nsjsonserialization 这个类的 datawithjsonobject:options:error:方法来实现,array 和 dictionary 序列化成 json 对象。方便在网络中传输。

2 代码实例
testdemo.m

 

[plain]
(void)conversetojson{ 
    nsmutabledictionary *dictionary = [[nsmutabledictionary alloc] init]; 
    [dictionary setvalue:@"archy" forkey:@"first name"]; 
    [dictionary setvalue:@"robbins" forkey:@"last name"]; 
    [dictionary setvalue:[nsnumber numberwithunsignedinteger:51] forkey:@"age"]; 
    nsarray *arrayofarchyschildren = [[nsarray alloc] initwithobjects: 
                                        @"anthony's son 1", 
                                        @"anthony's daughter 1", 
                                        @"anthony's son 2", 
                                        @"anthony's son 3", 
                                        @"anthony's daughter 2", nil]; 
    [dictionary setvalue:arrayofarchyschildren forkey:@"children"]; 
    nserror *error = nil; 
    //nsjsonwritingprettyprinted:指定生成的json数据应使用空格旨在使输出更加可读。如果这个选项是没有设置,最紧凑的可能生成json表示。 
    nsdata *jsondata = [nsjsonserialization 
                        datawithjsonobject:dictionary options:nsjsonwritingprettyprinted error:&error]; 
    if ([jsondata length] > 0 && error == nil){ 
        nslog(@"successfully serialized the dictionary into data."); 
        //nsdata转换为string 
        nsstring *jsonstring = [[nsstring alloc] initwithdata:jsondata encoding:nsutf8stringencoding]; 
        nslog(@"json string = %@", jsonstring); 
    } 
    else if ([jsondata length] == 0 && 
             error == nil){ 
        nslog(@"no data was returned after serialization."); 
    } 
    else if (error != nil){ 
        nslog(@"an error happened = %@", error); 
    } 
     
} 

-(void)conversetojson{
    nsmutabledictionary *dictionary = [[nsmutabledictionary alloc] init];
    [dictionary setvalue:@"archy" forkey:@"first name"];
    [dictionary setvalue:@"robbins" forkey:@"last name"];
    [dictionary setvalue:[nsnumber numberwithunsignedinteger:51] forkey:@"age"];
    nsarray *arrayofarchyschildren = [[nsarray alloc] initwithobjects:
                                        @"anthony's son 1",
                                        @"anthony's daughter 1",
                                        @"anthony's son 2",
                                        @"anthony's son 3",
                                        @"anthony's daughter 2", nil];
    [dictionary setvalue:arrayofarchyschildren forkey:@"children"];
    nserror *error = nil;
    //nsjsonwritingprettyprinted:指定生成的json数据应使用空格旨在使输出更加可读。如果这个选项是没有设置,最紧凑的可能生成json表示。
    nsdata *jsondata = [nsjsonserialization
                        datawithjsonobject:dictionary options:nsjsonwritingprettyprinted error:&error];
    if ([jsondata length] > 0 && error == nil){
        nslog(@"successfully serialized the dictionary into data.");
        //nsdata转换为string
        nsstring *jsonstring = [[nsstring alloc] initwithdata:jsondata encoding:nsutf8stringencoding];
        nslog(@"json string = %@", jsonstring);
    }
    else if ([jsondata length] == 0 &&
             error == nil){
        nslog(@"no data was returned after serialization.");
    }
    else if (error != nil){
        nslog(@"an error happened = %@", error);
    }
   
}
控制台结果

2013-05-13 17:14:26.087 tojsontest[4890:303] successfully serialized the dictionary into data.

2013-05-13 17:14:26.089 tojsontest[4890:303] json string = {

  "children" : [

    "anthony's son 1",

    "anthony's daughter 1",

    "anthony's son 2",

    "anthony's son 3",

    "anthony's daughter 2"

  ],

  "age" : 51,

  "first name" : "archy",

  "last name" : "robbins"

}