1：JSON转XML---通常把JSON数据写到Plist文件即可；

2：XML数据转JSON--

　　使用开源类 XMLReader 先XML数据先转换为 NSDictionary 即可

3： 开源类XMLReader 

1 // 2 //  XMLReader.h 3 // 4 // 5 /* 6     本类使用方法： 7         1：在使用的页面里面 导入本类 #import "XMLReader.h" 8         2: 调用XMLReader 的两个类方法 就可以了，就可以返回字典数据； 9         3：得到 NSDictionary数据，就是JSON 数据了；10  11  */12 #import 
      
       13 14 15 @interface XMLReader : NSObject 
       
        16 {17     NSMutableArray *dictionaryStack;18     NSMutableString *textInProgress;19     NSError **errorPointer;20 }21 22 //XML Data数据转换为 字典的方法；23 + (NSDictionary *)dictionaryForXMLData:(NSData *)data error:(NSError **)errorPointer;24 + (NSDictionary *)dictionaryForXMLString:(NSString *)string error:(NSError **)errorPointer;25 26 @end
       
      

1 //  2 //  XMLReader.m  3 //  4   5 #import "XMLReader.h"  6   7 NSString *const kXMLReaderTextNodeKey = @"text";  8   9 @interface XMLReader (Internal) 10  11 - (id)initWithError:(NSError **)error; 12 - (NSDictionary *)objectWithData:(NSData *)data; 13  14 @end 15  16  17 @implementation XMLReader 18  19 #pragma mark - 20 #pragma mark -公有的方法 21  22 //调用以下两个类方法即可； 23  24 + (NSDictionary *)dictionaryForXMLData:(NSData *)data error:(NSError **)error 25 { 26     XMLReader *reader = [[XMLReader alloc] initWithError:error]; 27     NSDictionary *rootDictionary = [reader objectWithData:data]; 28     [reader release]; 29     return rootDictionary; 30 } 31  32 + (NSDictionary *)dictionaryForXMLString:(NSString *)string error:(NSError **)error 33 { 34     NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding]; 35     return [XMLReader dictionaryForXMLData:data error:error]; 36 } 37  38 #pragma mark - 39 #pragma mark 以下为 私有处理方法，可以不关注； 40  41 - (id)initWithError:(NSError **)error 42 { 43     if (self = [super init]) 44     { 45         errorPointer = error; 46     } 47     return self; 48 } 49  50 - (void)dealloc 51 { 52     [dictionaryStack release]; 53     [textInProgress release]; 54     [super dealloc]; 55 } 56  57 - (NSDictionary *)objectWithData:(NSData *)data 58 { 59     // Clear out any old data 60     [dictionaryStack release]; 61     [textInProgress release]; 62      63     dictionaryStack = [[NSMutableArray alloc] init]; 64     textInProgress = [[NSMutableString alloc] init]; 65      66     // Initialize the stack with a fresh dictionary 67     [dictionaryStack addObject:[NSMutableDictionary dictionary]]; 68      69     // Parse the XML 70     NSXMLParser *parser = [[NSXMLParser alloc] initWithData:data]; 71     parser.delegate = self; 72     BOOL success = [parser parse]; 73      74     // Return the stack's root dictionary on success 75     if (success) 76     { 77         NSDictionary *resultDict = [dictionaryStack objectAtIndex:0]; 78         return resultDict; 79     } 80      81     return nil; 82 } 83  84 #pragma mark - 85 #pragma mark NSXMLParserDelegate methods 86  87 - (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict 88 { 89     // Get the dictionary for the current level in the stack 90     NSMutableDictionary *parentDict = [dictionaryStack lastObject]; 91  92     // Create the child dictionary for the new element, and initilaize it with the attributes 93     NSMutableDictionary *childDict = [NSMutableDictionary dictionary]; 94     [childDict addEntriesFromDictionary:attributeDict]; 95      96     // If there's already an item for this key, it means we need to create an array 97     id existingValue = [parentDict objectForKey:elementName]; 98     if (existingValue) 99     {100         NSMutableArray *array = nil;101         if ([existingValue isKindOfClass:[NSMutableArray class]])102         {103             // The array exists, so use it104             array = (NSMutableArray *) existingValue;105         }106         else107         {108             // Create an array if it doesn't exist109             array = [NSMutableArray array];110             [array addObject:existingValue];111 112             // Replace the child dictionary with an array of children dictionaries113             [parentDict setObject:array forKey:elementName];114         }115         116         // Add the new child dictionary to the array117         [array addObject:childDict];118     }119     else120     {121         // No existing value, so update the dictionary122         [parentDict setObject:childDict forKey:elementName];123     }124     125     // Update the stack126     [dictionaryStack addObject:childDict];127 }128 129 - (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName130 {131     // Update the parent dict with text info132     NSMutableDictionary *dictInProgress = [dictionaryStack lastObject];133     134     // Set the text property135     if ([textInProgress length] > 0)136     {137         [dictInProgress setObject:textInProgress forKey:kXMLReaderTextNodeKey];138 139         // Reset the text140         [textInProgress release];141         textInProgress = [[NSMutableString alloc] init];142     }143     144     // Pop the current dict145     [dictionaryStack removeLastObject];146 }147 148 - (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string149 {150     // Build the text value151     [textInProgress appendString:string];152 }153 154 - (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError155 {156     // Set the error pointer to the parser's error object157     *errorPointer = parseError;158 }159 160 @end

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