springdata的nativeQuery的语句能否指定从外部sql文件或xml文件读取?

发布网友发布时间：2022-04-07 20:52

共4个回答

懂视网时间：2022-04-08 01:13

实现对象数据映射。其框架库在github上能找到。以下代码将通过LKDBHelper实现增删查改。

1 实现数据对应的Bean对象，以下提供.h文件。

#import <Foundation/Foundation.h>

@interface WBUser : NSObject

@property (nonatomic,copy) NSString *userName;

@property (nonatomic,assign) int age;

@end

2 提供实现的Dao层。

WBUserDao.h

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

@interface WBUserDao : NSObject

+(instancetype)daoWithEntityClass:(Class)aclass;

-(void)saveUser:(WBUser *)user;

-(WBUser *)loadUserWithWherecase:(NSString *)where;

-(BOOL)updateUserWithWherecase:(NSString *)where;

-(void)deleteWithWherecase:(NSString *)where;

@end

WBUserDao.m

#import "WBUserDao.h"
#import "LKDBHelper.h"

@interface WBUserDao ()

@property (nonatomic,strong) Class entityClass;
@property (nonatomic,strong) LKDBHelper *gobalHelper;

@end

@implementation WBUserDao

+(instancetype)daoWithEntityClass:(Class)aclass
{
 WBUserDao *dao=[[[self class] alloc] initWithEntityClass:aclass];
 return dao;
}

-(instancetype)initWithEntityClass:(Class)aclass
{
 if (self=[super init]) {
 _entityClass=aclass;
 _gobalHelper=[LKDBHelper getUsingLKDBHelper];
 [_gobalHelper createTableWithModelClass:[_entityClass class]];
 }
 return self;
}

-(void)saveUser:(WBUser *)user
{
 NSLog(@"%d",[_gobalHelper insertToDB:user]);
}

-(WBUser *)loadUserWithWherecase:(NSString *)where
{
 return [_gobalHelper searchSingle:[WBUser class] where:where orderBy:nil];
}

-(BOOL)updateUserWithWherecase:(NSString *)where
{
 return [_gobalHelper updateToDB:[WBUser class] set:@"age = 15 " where:where];
}

-(void)deleteWithWherecase:(NSString *)where
{
 [_gobalHelper deleteWithClass:[WBUser class] where:where callback:^(BOOL result) {
 NSLog(@"delete result :%d",result);
 }];
}

@end

3 以下代码显示如何调用。我们在ViewDidLoad中实现

- (void)viewDidLoad {
 [super viewDidLoad];
 
 WBUser *user=[[WBUser alloc] init];
 user.userName=@"awdawda";
 user.age=18;
 
 WBUserDao *dao=[WBUserDao daoWithEntityClass:[user class]];
 [dao saveUser:user];
 
 WBUser *userData=[dao loadUserWithWherecase:@"userName='awdawda'"];
 
 BOOL updateFlag=[dao updateUserWithWherecase:@"userName='awdawda'"];
 
 WBUser *userData2=[dao loadUserWithWherecase:@"userName='awdawda'"];
 
 NSLog(@"%d %d",updateFlag,userData2.age);
 
 [dao deleteWithWherecase:@"userName='awdawda'"];
 
}

Tip:在增删查改中，LKDBhelper实现的方式还有很多很多。具体看需求。gitHub:点击打开链接

LKDBHelper-ORM框架

标签：

热心网友时间：2022-04-07 22:21

不换行就是;
因为springdata我也不熟,给你说一个最笨的方法:
写成下面样子,放在txt文件中:
x= select *
from y;
读取时组成一个字符串,然后用split(";") 得到数组;然后遍历数组,截取等号前面的为key,后面的为value,放在map里,想取哪个取哪个

热心网友时间：2022-04-07 23:39

单表查询不需要自己写sql，多表查询springdataJpa真的不建议这么使用，底层是hibernate，很重，连表操作很影响性能。

热心网友时间：2022-04-08 01:14

自己写一个helper读文件不就行了？
再说java有流行的orm框架（hibernate之类）可以解决你说的问题把