JDBC ResultSet-无可用数据 [英] JDBC ResultSet - No data is available

问题描述

我是Java的新手，我试图将表中的所有数据打印出来

I'm new to java, i tried to print all data in the table

    Statement stmt=connection.createStatement();
    String sql ="INSERT INTO contacts(name,email)VALUES('ABC','[e-mail]')";
    stmt.execute(sql);
    ResultSet rs=stmt.executeQuery("SELECT*FROM contacts");
    System.out.println(rs.getString("name"));

得到了

Exception in thread "main" org.h2.jdbc.JdbcSQLException: No data is available [2000-173]

推荐答案

您需要先调用rs.next()，然后再调用rs.getString("...").

You need to call rs.next() before calling rs.getString("...").

...
ResultSet rs=stmt.executeQuery("SELECT * FROM contacts");

while(rs.next()) {
    System.out.println(rs.getString("name"));
}

---

如果您只希望有1行，那么您也可以这样做:

---

If you're expecting only 1 row, then you can also do:

...
ResultSet rs=stmt.executeQuery("SELECT * FROM contacts");

if(rs.next()) {
    System.out.println(rs.getString("name"));
}

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