Question

所以在我的应用程序中，我试图迭代我的rs记录。我希望能够一次打印出一大堆记录，如果我有100条记录并且缺少记录3,12-15和40-60，我希望它显示已读取的记录。所以我可以知道其他记录丢失/跳过。我在这里发布了一个更完整的代码Java JDBC display first 500 records at a time, commit, than display the next 500 records and etc

updated records 1-2 updated records 4-11 updated records 13-39 updated records 61-100

 try {
             int rowCount = 0;   
           while (rs.next()) {


                 String ingressflag = rs.getString("ingress_flag");     
                 String egressflag = rs.getString("egress_flag");       
                 String ceingressflag = rs.getString("ce_ingress_flag"); 
                 String ceegressflag = rs.getString("ce_egress_flag");  
                 int profileid = rs.getInt("profile_id");               

                preparedStatement.setString(1, ingressflag);
                preparedStatement.setString(2, egressflag);
                preparedStatement.setString(3, ceingressflag);
                preparedStatement.setString(4, ceegressflag);
                preparedStatement.setInt(5, profileid);

                preparedStatement.addBatch();
                rowCount++;
               // System.out.println("profileid updated : " + profileid     +  " timestamp " +  new java.util.Date()  + "\n");

           }

Answer 1

我会使用一系列布尔值，这些布尔值与您拥有的记录数量相同。然后，当且仅当该记录已更新时，将每个对应值设置为True。

然后从这个数组中你可以通过简单地循环遍历数组，以你建议的形式给出输出：

int first;
int last = 0;
while(!records[last]) //skip through records 1-x that are missing
    last++;
first = last+1;

for(int i = last; i < numRecords; i++){
    if(records[i]) //keep going if record there
        last++;
    else{ //otherwise print out previous "streak" and start anew
        if(first == last) //streak of 1
            System.out.println("updated record " + first);
        else //streak of >1
            System.out.println("updated records " + first + "-" + last);
        while(!records[i]) //skip over entire missing section
            i++;
        first = i+1; //new first is next valid value
        last = first;
    }
}

if(records[numRecords-1])//if end reached without printing last streak
    System.out.println("updated records " + first + "-" + last); //print it now

Answer 2

如果您想查找哪个profile_id缺失，可以尝试声明int类型的变量说expectedId并初始化到表格的起始profile_id你的情况1.然后在while循环中检查返回的profile_id是否等于expectedId如果没有打印出消息，最后将expectedId增加1，如下图所示。

int expectedId = 1;
while (rs.next()) {
    //All your code
    if(expectedId != profileid){
       System.out.println ("Profile id "+expectedId+" to "+(profileid-1)+" missing.";
       expectedId = profileid;
    }
    expectedId++;
}

每当序列丢失时，它会给出一个输出，说明缺少的id。

Java如何显示读取的记录范围

2 个答案: