目录
1. NSUserDefaults
2. NSCoding 归档
3. sqlite
4. FMDB
5. CoreData
6. 读写文件
- NSUserDefaults
用于存储系统自带类型， 缺点：不能存储自定义类类型。
// 设值（必须调用synchronize）
[[NSUserDefaults standardUserDefaults]setObject:@(10) forKey:@"age"];
[[NSUserDefaults standardUserDefaults]synchronize];
// 取值
[[NSUserDefaults standardUserDefaults]objectForKey:@"age"];
其他设值方式（必须调用synchronize）
[[NSUserDefaults standardUserDefaults]setBool:true forKey:@"sex"];
[[NSUserDefaults standardUserDefaults]setInteger:10 forKey:@"age"];
[[NSUserDefaults standardUserDefaults]setDouble:10.0 forKey:@"weight"];
[[NSUserDefaults standardUserDefaults]setFloat:10.0f forKey:@"weight"];
- NSCoding
用来存储自定义类类型。
1. 创建归档类（遵守NSCoding协议实现encodeWithCoder、initWithCoder）
Student.h
#import <Foundation/Foundation.h>
@interface Student : NSObject<NSCoding>
@property (nonatomic,copy) NSString *name;
@property (nonatomic,assign) int age;
@end
Student.m
#import "Student.h"
@implementation Student
// 编码
-(void)encodeWithCoder:(NSCoder *)aCoder{
[aCoder encodeObject:self.name forKey:@"name"];
[aCoder encodeInteger:self.age forKey:@"age"];
}
// 解码
-(instancetype)initWithCoder:(NSCoder *)aDecoder{
if(self){
self.name=[aDecoder decodeObjectForKey:@"name"];
self.age=(int)[aDecoder decodeIntegerForKey:@"age"];
}
return self;
}
@end
2.归档、解档
Student *student=[Student new];
// 路径
NSString *path=[NSString stringWithFormat:@"%@/Documents/hello.archive",NSHomeDirectory()];
// 归档
[NSKeyedArchiver archiveRootObject:student toFile:path];
// 解档
student=[NSKeyedUnarchiver unarchiveObjectWithFile:path];
- sqlite
SQLite是一个由C编写的SQL嵌入式轻量级关系型数据库(线程不安全）
DBManger.h
#import <Foundation/Foundation.h>
@interface DBManger : NSObject<NSCopying,NSMutableCopying>
+(instancetype)sharedSingleton;
@end
DBManger.m
#import "DBManger.h"
#import <sqlite3.h>
@interface DBManger()
@end
@implementation DBManger
// ---------- 单例 ---------
static DBManger *_singleton;
+(instancetype)sharedSingleton{
return [self new];
}
+(instancetype)allocWithZone:(struct _NSZone *)zone{
@synchronized (self) {
if(!_singleton){
_singleton=[super allocWithZone:zone];
}
}
return _singleton;
}
// 避免使用copy mutableCopy方法时再次创建
-(id)copyWithZone:(NSZone *)zone{
return _singleton;
}
-(id)mutableCopyWithZone:(NSZone *)zone{
return _singleton;
}
// ------------ 操作数据库 -----------
static sqlite3 *db = nil;
/*
打开数据库
*/
-(void)openDB{
// 有db则打开，没db则先创建再打开
NSString *path=[NSString stringWithFormat:@"%@/Documents/test.db",NSHomeDirectory()];
if(sqlite3_open([path UTF8String], &db)==SQLITE_OK){ // 打开db成功
NSLog(@"数据库打开成功");
}
}
/*
关闭数据库
*/
-(void)closeDB{
if (sqlite3_close(db) == SQLITE_OK) {
NSLog(@"数据库关闭成功");
db = nil;
} else {
NSLog(@"数据库关闭失败");
}
}
/*
创建表
*/
-(void)createTable{
//
[self openDB];
NSString *sql=@"CREATE TABLE IF NOT EXISTS good(good_id INTEGER PRIMARY KEY AUTOINCREMENT,good_name CHAR(50) NOT NULL DEFAULT 'good',good_content CHAR(200),good_pic CHAR(100));";
char *error;
if(sqlite3_exec(db,[sql UTF8String], nil, nil, &error)==SQLITE_OK){
NSLog(@"创建表成功");
}else{
NSLog(@"创建表失败 = %s",error);
}
[self closeDB];
}
/*
删除表
*/
-(void)dropTable{
//
[self openDB];
NSString *sql=@"DROP TABLE good;";
char *error;
if(sqlite3_exec(db,[sql UTF8String], nil, nil, &error)==SQLITE_OK){
NSLog(@"创建表成功");
}else{
NSLog(@"创建表失败 = %s",error);
}
[self closeDB];
}
/*
更新表
*/
- (void)insertData{
[self openDB];
sqlite3_stmt *stmt = nil;
NSString *sqlStr = @"INSERT good(good_name,good_content) VALUES(?,?);";
// sqlStr="UPDATE TABLE good SET good_name=? WHERE good_id=?"
// sqlStr="DELETE FROM good WHERE good_name=?"
if (sqlite3_prepare_v2(db, sqlStr.UTF8String, -1, &stmt, NULL) == SQLITE_OK) {
// 索引从1开始，代表第几个问号
sqlite3_bind_int(stmt, 1, 10);
sqlite3_bind_text(stmt, 2, sqlStr.UTF8String, -1, SQLITE_TRANSIENT);
if (sqlite3_step(stmt) == SQLITE_DONE) {
NSLog(@"新增成功");
}
} else {
NSLog(@"新增数据不合法");
}
sqlite3_finalize(stmt);
[self closeDB];
}
/*
查询表
*/
- (void)queryData{
[self openDB];
sqlite3_stmt *stmt = nil;
NSString *sqlStr = @"SELECT * FROM good";
if (sqlite3_prepare_v2(db, sqlStr.UTF8String, -1, &stmt, NULL) == SQLITE_OK) {
if (!(sqlite3_step(stmt) == SQLITE_DONE)) {
// 单步获取每行（SQLITE_ROW为一行数据）
while (sqlite3_step(stmt) == SQLITE_ROW) {
int ID = sqlite3_column_int(stmt, 0);
const unsigned char *name = sqlite3_column_text(stmt, 1);
const unsigned char *content = sqlite3_column_text(stmt, 2);
const unsigned char *pic = sqlite3_column_text(stmt, 3);
NSLog(@"ID = %d , name = %@ , sex = %@, description = %@",ID,[NSString stringWithUTF8String:(const char *)name],[NSString stringWithUTF8String:(const char *)content],[NSString stringWithUTF8String:(const char *)pic]);
}
} else {
NSLog(@"查询语句完成");
}
} else {
NSLog(@"查询语句不合法");
}
//
sqlite3_finalize(stmt);
[self closeDB];
}
@end
- FMDB
- CoreData
- 读写文件
待续。。。
