微信小程序页面返回时通过 channel 传值示例

问题：页面 A 打开页面 B ，B 如何将参数通过 EventChannel 传回 A 解决… Read More

不错的 icon 网站

https://www.iconfont.cn/ https://fontawesome.com… Read More

Selenuim 、 PhantomJS 、puppeteer 更好的替代品

问题： puppeteer 能较好操作 chrome ，有没有更好替代品呢？解决： https… Read More

JPA n次查询问题优化

问题：使用 Spring Data JPA 定义 Repo find方法时，发现会执行了N+2条SQL 。 … Read More

JPA 继承例子

问题： Entity Car 有两类Entity BigCar 及Entity SmallCar；数据库中对… Read More

JPA Resolved [java.lang.IllegalArgumentException: Id must be assignable to Serializable: null]

问题： JPA Entity 如下

@Table (name= "EMP") 
@Inheritance
@DiscriminatorColumn (name="EMP TPE") 
public abstract class Employee {...}

@Entity
@DiscriminatorValue ("CEmp")
public class contractemployee extenas Employee{...}

@MappedSuperclass
public abstract class CompanyEmployee extends Employee {...}

@Entity
@DiscriminatorValue ("FTEmp")
public class FullTimeEmployee extenas companyemployee {....}

@Entity (name= "PTEmp")
public class PartTimeEmployee extends CompanyEmployee {....}

@Table (name= "EMP")

@Inheritance

@DiscriminatorColumn (name="EMP TPE")

public abstract class Employee {...}

@Entity

@DiscriminatorValue ("CEmp")

public class contractemployee extenas Employee{...}

@MappedSuperclass

public abstract class CompanyEmployee extends Employee {...}

@Entity

@DiscriminatorValue ("FTEmp")

public class FullTimeEmployee extenas companyemployee {....}

@Entity (name= "PTEmp")

public class PartTimeEmployee extends CompanyEmployee {....}

&nbs… Read More

IT问题