处理QueryDSL中的可选参数 [英] Handle optional parameters in QueryDSL

问题描述

我在SpringData中使用QueryDSL。
我有表说，员工我已经创建了实体类说， EmployeeEntity
I写了以下服务方法

I am using QueryDSL with SpringData. I have Table say, Employee and I have created entity class say, EmployeeEntity I have written following service method

public EmployeeEntity getEmployees(String firstName, String lastName)
{
    QEmployeeEntity employee = QEmployeeEntity.employeeEntity;
    BooleanExpression query = null;
    if(firstName != null)
    {
        query = employee.firstName.eq(firstName);
    }
    if(lastName != null)
    {
        query = query.and(employee.lastName.eq(lastName)); // NPException if firstName is null as query will be NULL
    }
    return empployeeDAO.findAll(query);
}

如上所述，我评论了 NPException 。如何使用Spring数据在 QueryDSL 中使用 QueryDSL 作为可选参数？

As in above I commented the NPException. How to use QueryDSL for optional Parameters in QueryDSL using Spring Data?

谢谢：）

推荐答案

BooleanBuilder 可用作布尔表达式的动态构建器：

BooleanBuilder can be used as a dynamic builder for boolean expressions:

public EmployeeEntity getEmployees(String firstName, String lastName) {
    QEmployeeEntity employee = QEmployeeEntity.employeeEntity;
    BooleanBuilder where = new BooleanBuilder();
    if (firstName != null) {
        where.and(employee.firstName.eq(firstName));
    }
    if (lastName != null) {
        where.and(employee.lastName.eq(lastName));
    }
    return empployeeDAO.findAll(where);
}

这篇关于处理QueryDSL中的可选参数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！