java - JPQL 中带有 IN 运算符的枚举列表

Question

哪个缺少以下 JPQL 查询？

SELECT h FROM WorkFlowHistory h WHERE h.referenceNo = :referenceNo 
AND h.workflowTask IN ('CONFIRMATION','PAYMENT','ISSUING')

错误:

invalid IN expression argument [CONFIRMATION]

动态查询方法

public List<WorkFlowHistory> findWorkFlowHistoryByRefNo(String refNo, WorkflowTask ...workflowTasks) {
    ...
    StringBuffer buffer = new StringBuffer("SELECT h FROM WorkFlowHistory h WHERE h.referenceNo = :referenceNo");
    if(workflowTasks != null && workflowTasks.length > 0) {
        buffer.append(" AND h.workflowTask IN (");
        for (int i = 0; i < workflowTasks.length; i++) {
            buffer.append("'" + workflowTasks[i] + "'");
            if ((i + 1) != workflowTasks.length) {
                buffer.append(",");
            }
        }
        buffer.append(")");
    }
    Query q = em.createQuery(buffer.toString());
    ....
}

我的枚举类

public enum WorkflowTask {
    UNDERWRITING("Underwriting"),
    SURVEY("Survey"),
    APPROVAL("Approval"),
    INFORM("Inform"),
    CONFIRMATION("Confirmation"),
    PAYMENT("Payment"),
    PROPOSAL_REJECT("Proposal Reject"),
    ISSUING("Issuing");

    private String label;

    private WorkflowTask(String label) {
        this.label = label;
    }

    public String getLabel() {
        return label;
    }
}   

Answer 1

我认为问题在于数据库中枚举的表示。您的枚举如何映射到数据库 Ordinal 或 String 中？

最好的方法是将枚举作为 JPQL 查询中的参数占位符:

SELECT h FROM WorkFlowHistory h WHERE h.referenceNo = :referenceNo 
AND h.workflowTask IN :workflowTasks

并将其作为参数添加到您的查询中，如下所示:

...
List<WorkflowTask> workflowTasks=Arrays.asList({WorkflowTask.CONFIRMATION, WorkflowTask.PAYMENT WorkflowTask.ISSUING });
...
Query q = em.createQuery(buffer.toString());
q.addParameter("workflowTasks", workflowTasks);

这样你就不必考虑你的枚举在数据库中如何表示。