java - java在方法String []。length中返回String []不正确

我想要的是将数据插入数组String []，然后打印数组值。
返回的String []类型方法是

public String[] getRequirementDocIDofProject(String testprojectName)
        throws SQLException, InstantiationException, IllegalAccessException, ClassNotFoundException {
    String req_doc_ids[] = null;
    String str_sqlQuery = "select * from req_specs INNER JOIN nodes_hierarchy nh " +
            "on nh.id=req_specs.testproject_id  " +
            "INNER JOIN requirements reqs " +
            "on req_specs.id =reqs.srs_id where nh.name='" + testprojectName + "'";
    int count = 0;
    int n = 0;
    initDB();
    resultSet = statement.executeQuery(str_sqlQuery);
    while (resultSet.next()){
        count = Integer.parseInt(resultSet.getString(1));
    }
    req_doc_ids = new String[count];

    resultSet = statement.executeQuery(str_sqlQuery);
    while (resultSet.next()) {
        req_doc_ids[n] = resultSet.getString("req_doc_id");
        System.out.println("REQID=" + req_doc_ids[n]);
        n++;
    }
    close();
    System.out.println("n==" + n);
    return req_doc_ids;
}

调用方法的代码是

DBConnection dbcon = new DBConnection();
String req_doc_ids[] = dbcon.getRequirementDocIDofProject("XXXX");
System.out.println(req_doc_ids.length);

控制台中的打印消息是
REQID = TECH-6104
REQID = TECH-6686
REQID = TECH-5391
REQID = TECH-5965
REQID = TECH-6530
REQID = TECH-6729
REQID = TECH-7082
REQID = TECH-7107
REQID = TECH-7184
n == 9
7166

为什么req_doc_ids.length的值为7166而不是9

最佳答案

7166来自结果集的第1列-它是最后一行中的值。

while(resultSet.next()){
    count=Integer.parseInt(resultSet.getString(1));
}

相反，您可能的意思是：

while(resultSet.next()){
    count++;
}

请注意，这是创建数组的不必要的低效方式。使用List代替；或者，使用结果集API上的方法直接获取行数。

关于java - java在方法String []。length中返回String []不正确，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/53811629/