设置外键时出现非法参数错误

Question

  

org.springframework.web.util.NestedServletException：处理程序调度   失败;嵌套异常是java.lang.Error：未解析的编译   问题：方法setTblDepartment（TblDepartment）中的类型   TblProject不适用于参数（Long）

服务层中的代码

public void setFkDeptIdForProject(Long projectId, Long departmentId) {
    TblProject existProj=projectDAO.get(projectId);
    TblDepartment dept= new TblDepartment();
    dept.setPkDepartmentId(departmentId);
    existProj.setTblDepartment(dept);
    projectDAO.update(existProj);
}

的 TblProject.class

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "fk_department_id")
public TblDepartment getTblDepartment() {
    return this.tblDepartment;
}

public void setTblDepartment(TblDepartment tblDepartment) {
    this.tblDepartment = tblDepartment;
}