问题描述
我正在使用带有 SpringData 的 QueryDSL.我有表说,Employee,我创建了实体类说,EmployeeEntity我写了以下 service 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,我注释了 NPException.如何使用 Spring Data 将 QueryDSL 用于 QueryDSL 中的可选参数?
As in above I commented the NPException. How to use QueryDSL for optional Parameters in QueryDSL using Spring Data?
谢谢你:)
推荐答案
BooleanBuilder 可以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); }