ios数据存储的几种常用方式

NSString *rootDir = NSHomeDirectory();
NSString *path = [rootDir stringByAppendingPathComponent:@"test.txt"];
 
NSMutableData *data = [NSMutable data];
NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingMutableData:data];
 
NSArray *array = @[@"one",@"two"];
[archiver encodeInt:100 forKey:@"age"];//相当于SharedPreference的putInteger(key,value);
[archiver encodeObject:array forKey:@"names"];//
[archiver finishEncoding];//此方法调用，则将数据存入data
[archiver release];
 
if([data writeToFile:path atomically:YES]){
    NSLog(@"对象存入文件成功");
}

NSData *data = [NSData dataWithContentOfFile:path];
NSKeyedArchiver *unarchiver =[[NSKeyedArchiver alloc] initForReadingWithData:data];
int age = [unarchiver decodeIntForKey:@"age"];//取出值
NSArray *array = [unarchiver decodeObjectForKey:@"names"];
[archiver release];

    
//1. 存入数据
NSArray *array = @[@"abc",@"d"];
NSUserDefaults *userDefault = [NSUserDefaults standardUserDefaults];
[userDefault setInteger:123 forKey:@"number"];
[userDefault setObject:array forKey:@"array"];
[userDefault synchronize];//存入文件
 
//2. 取出数据
NSInteger number = [userDefault integerForKey:@"number"];
NSArray *array = [userDefault objectForKey:@"array"];

1 NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,  NSUserDomainMask,YES);
2 NSString *ourDocumentPath =[documentPaths objectAtIndex:0];
3 
4 //使用C函数NSSearchPathForDirectoriesInDomains来获得沙盒中目录的全路径。
该函数有三个参数，目录类型、he domain mask、布尔值。其中布尔值表示是否需要通过～扩展路径。
而且第一个参数是不变的，即为NSSearchPathDirectory 。在IOS中后两个参数也是不变的，即为：NSUserDomainMask 和 YES。

NSString *sandboxPath = NSHomeDirectory();
NSString *documentPath = [sandboxPath stringByAppendingPathComponent:@"Documents"];
//将Documents添加到sandbox路径上

NSString *FileName=[documentDirectory stringByAppendingPathComponent:saveFileName];
//saveFileName就是保存文件的文件名

[data writeToFile:saveFileName atomically:YES];
//将NSData类型对象data写入文件，文件名为saveFileName

NSData data=[NSData dataWithContentsOfFile:saveFileName options:0 error:NULL];
//从saveFileName中读取出数据

NSArray *documentsPaths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask , YES);
NSString *databaseFilePath=[[documentsPaths objectAtIndex:0] stringByAppendingPathComponent:@"mydb"];
//打开数据库

  if (sqlite3_open([databaseFilePath UTF8String], &database)==SQLITE_OK)

{ 
        NSLog(@"sqlite dadabase is opened."); 
}
else{

    return;

}//打开不成功就返回

//在打开了数据库的前提下，如果数据库没有表，那就开始建表
char *error; 
const char *createSql="create table(id integer primary key autoincrement, name text)";
if (sqlite3_exec(database, createSql, NULL, NULL, &error)==SQLITE_OK) { 
        NSLog(@"create table is ok."); 
}
else
{
       NSLog(@"error: %s",error);
       sqlite3_free(error);//每次使用完毕清空error字符串，提供给下一次使用
} 

//建表完成之后，就开始插入记录：

const char *insertSql="insert into a person (name) values(‘gg’)"; 
if (sqlite3_exec(database, insertSql, NULL, NULL, &error)==SQLITE_OK) { 
        NSLog(@"insert operation is ok."); 
}

else
{
       NSLog(@"error: %s",error);
       sqlite3_free(error);//每次使用完毕清空error字符串，提供给下一次使用
} 

//查询记录：

const char *selectSql="select id,name from a person"; 
sqlite3_stmt *statement; 
if (sqlite3_prepare_v2(database,selectSql, -1, &statement, nil)==SQLITE_OK) { 
        NSLog(@"select operation is ok."); 
}
else
{
       NSLog(@"error: %s",error);
       sqlite3_free(error);
} 
while(sqlite3_step(statement)==SQLITE_ROW) { 
int _id=sqlite3_column_int(statement, 0); 
NSString *name=(char*)sqlite3_column_text(statement, 1); 
NSLog(@"row>>id %i, name %s",_id,name); 
}
sqlite3_finalize(statement);

//最后，关闭数据库：

sqlite3_close(database);