iOS之集合对象：将NSArray和NSDictionary两个集合对象写到一个文件中

代码例子：将两个NSDictionary对象和一个NSArray对象放入到一个NSArray对象中，再将这个对象的内容输出。代码如下：

//
//  main.m
//  NSDictionary导入导出
//
//

#import <Foundation/Foundation.h>
#import "Person.h"

int main(int argc, const char * argv[])
{

    @autoreleasepool {

        NSDictionary * dict_1 = [NSDictionary dictionaryWithObjectsAndKeys:@"Wangming", @"N1",
                                 @"Li Junyan", @"N2",
                                 nil];
        NSDictionary * dict_2 = [NSDictionary dictionaryWithObjectsAndKeys:@"iOS Teach Book", @"B1",
                                 @"HTML Book", @"B2",
                                 nil];
        NSArray * schools = [NSArray arrayWithObjects:@"Qinghua", @"Wuda", @"Chongda", nil];

        NSArray * array = [NSArray arrayWithObjects:dict_1, dict_2, schools, nil];

        NSString * path = @"/Users/admin/Desktop/person.txt";

        [array writeToFile:path atomically:YES];
    }
    return 0;
}

程序输出结果：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<array>
    <dict>
        <key>N1</key>
        <string>Wangming</string>
        <key>N2</key>
        <string>Li Junyan</string>
    </dict>
    <dict>
        <key>B1</key>
        <string>iOS Teach Book</string>
        <key>B2</key>
        <string>HTML Book</string>
    </dict>
    <array>
        <string>Qinghua</string>
        <string>Wuda</string>
        <string>Chongda</string>
    </array>
</array>
</plist>

程序运行成功。

集合对象写入到文件中遵循上面这个XML文档的规则，同样的，要想从一个文件中获取内容来创建一个集合对象，这个文件同样要遵循上述XML文档的规则和Property List Types and Objects规则。