java - 修改反射(reflect)本地引用的类级别哈希图更改

我正在尝试根据insuranceid将保险详细信息保存到数据库，或者如果数据库中已经存在insuranceid则进行更新。问题是，当我尝试保存多个保险明细时，它给出了ConcurrentModificationException。在调试时，我发现第1个周期没问题，第1个保险详细信息已成功保存到数据库中。但是当下一个保险详细信息存储时，它给出了例外。另一件事是，这里我正在修改主HashMap（PatientId，HashMap（insuranceId，InsuranceInfo）），并且更改反映在本地引用中，该ID是在当前method（）中添加到insuranceMap变量中。请尝试帮助我

这是我的储存方式...

public void storeInsuranceInformationToDataBase(int patientId) throws SQLException
{
    //It gives arrayList of isuranceIds which are already in the data base.
    ArrayList<Integer> insuranceIdsListInDatabase = getInsuranceIdsListInDatabase();

    //It returns HashMap of insurance ids for given patient id.
    HashMap<Integer, InsuranceInfo> insuranceMap = getInsuranceDetails(patientId);
    Set<Integer> insuranceIdsInHashMap = insuranceMap.keySet();

    //Here I am getting ConcurrentModificationException
    for (int insuranceIdInHashMap : insuranceIdsInHashMap)
    {
        //Here I am comparing the both ids..
        if (insuranceIdsListInDatabase.contains(insuranceIdInHashMap))
        {
            String updateInsuranceQuery = "UPDATE jp_InsuranceInfo SET  typeOfPolicy='" + insuranceMap.get(insuranceIdInHashMap).getTypeOfPolicy() + "', amount=" + insuranceMap.get(insuranceIdInHashMap).getAmount() + ", duration=" + insuranceMap.get(insuranceIdInHashMap).getDuration()
                    + ", companyName='" + insuranceMap.get(insuranceIdInHashMap).getCompanyName() + "' WHERE insuranceId=" + insuranceIdInHashMap + ";";

            getDataBase().getStatement().executeUpdate(updateInsuranceQuery);
        }
        else
        {
            String insertInsuranceQuery = "INSERT INTO jp_InsuranceInfo VALUES(" + insuranceMap.get(insuranceIdInHashMap).getPatientId() + ",'" + insuranceMap.get(insuranceIdInHashMap).getTypeOfPolicy() + "'," + insuranceMap.get(insuranceIdInHashMap).getAmount() + ","
                    + insuranceMap.get(insuranceIdInHashMap).getDuration() + ",'" + insuranceMap.get(insuranceIdInHashMap).getCompanyName() + "')";

            getDataBase().getStatement().executeUpdate(insertInsuranceQuery);

            ResultSet generatedInsuranceId = getDataBase().getStatement().executeQuery("SELECT SCOPE_IDENTITY()");
            int newInsuranceId = 0;
            if (generatedInsuranceId.next())
            {
                newInsuranceId = generatedInsuranceId.getInt(1);
            }

            //Here it returns an insurance object which contains insurance details
            InsuranceInfo insuranceObject = insuranceMap.get(insuranceIdInHashMap);
            insuranceObject.setInsuranceId(newInsuranceId);
            //Here I am trying to store the newly inserted insurance object into main hashmap
            storeInsuranceInfoToHashMap(patientId, insuranceObject);

            //I am removing previous insurance object with temporary insurance id
            getInsuranceMap().get(patientId).remove(insuranceIdInHashMap);

            // Adding newly generated insurance id to array list
            getInsuranceIdsListInDatabase().add(newInsuranceId);
        }
    }

最佳答案

好吧，没什么奇怪的。您尝试遍历项目时将新项目添加到Map对象中。

我的建议是尝试将通过Map迭代时创建的保险数据保存到临时的Map对象中。并且，在完成迭代Map之后。然后，您可以将临时地图保存到初始地图中。

例如：

public void storeInsuranceInformationToDataBase(int patientId) throws SQLException
{
    //It gives arrayList of isuranceIds which are already in the data base.
    ArrayList<Integer> insuranceIdsListInDatabase = getInsuranceIdsListInDatabase();

    //It returns HashMap of insurance ids for given patient id.
    HashMap<Integer, InsuranceInfo> insuranceMap = getInsuranceDetails(patientId);
    Map<Integer, InsuranceInfo> tempInsuranceMap = new HashMap<>();
    Set<Integer> insuranceIdsInHashMap = insuranceMap.keySet();

    //Here I am getting ConcurrentModificationException
    for (int insuranceIdInHashMap : insuranceIdsInHashMap)
    {
        //Here I am comparing the both ids..
        if (insuranceIdsListInDatabase.contains(insuranceIdInHashMap))
        {
            String updateInsuranceQuery = "UPDATE jp_InsuranceInfo SET  typeOfPolicy='" + insuranceMap.get(insuranceIdInHashMap).getTypeOfPolicy() + "', amount=" + insuranceMap.get(insuranceIdInHashMap).getAmount() + ", duration=" + insuranceMap.get(insuranceIdInHashMap).getDuration()
                    + ", companyName='" + insuranceMap.get(insuranceIdInHashMap).getCompanyName() + "' WHERE insuranceId=" + insuranceIdInHashMap + ";";

            getDataBase().getStatement().executeUpdate(updateInsuranceQuery);
        }
        else
        {
            String insertInsuranceQuery = "INSERT INTO jp_InsuranceInfo VALUES(" + insuranceMap.get(insuranceIdInHashMap).getPatientId() + ",'" + insuranceMap.get(insuranceIdInHashMap).getTypeOfPolicy() + "'," + insuranceMap.get(insuranceIdInHashMap).getAmount() + ","
                    + insuranceMap.get(insuranceIdInHashMap).getDuration() + ",'" + insuranceMap.get(insuranceIdInHashMap).getCompanyName() + "')";

            getDataBase().getStatement().executeUpdate(insertInsuranceQuery);

            ResultSet generatedInsuranceId = getDataBase().getStatement().executeQuery("SELECT SCOPE_IDENTITY()");
            int newInsuranceId = 0;
            if (generatedInsuranceId.next())
            {
                newInsuranceId = generatedInsuranceId.getInt(1);
            }

            //Here it returns an insurance object which contains insurance details
            InsuranceInfo insuranceObject = insuranceMap.get(insuranceIdInHashMap);
            insuranceObject.setInsuranceId(newInsuranceId);
            //Here I am trying to store the newly inserted insurance object into main hashmap
            storeInsuranceInfoToHashMap(patientId, insuranceObject); <-- make this function to save those information into the temporary map

            //I am removing previous insurance object with temporary insurance id
            getInsuranceMap().get(patientId).remove(insuranceIdInHashMap);

            // Adding newly generated insurance id to array list
            getInsuranceIdsListInDatabase().add(newInsuranceId);
        }
    }
    insuranceMap.putAll(tempInsuranceMap);
}

关于java - 修改反射(reflect)本地引用的类级别哈希图更改，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/31240304/