BooleanBuilder可以用作布尔表达式的动态生成器：
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);}
