java - 如何判断获取的Java ResultSet是否为空？

Question

Class.forName("org.sqlite.JDBC");
Connection conn =
    DriverManager.getConnection("jdbc:sqlite:userdata.db");
Statement stat = conn.createStatement();

ResultSet rs = stat.executeQuery("SELECT * from table WHERE is_query_processed = 0;");

int rowcount = rs.getRow(); 
System.out.println("Row count = "+rowcount); // output 1

rs.first(); // This statement generates an exception

为什么会这样？

Answer 1

我通常使用的模式如下:

boolean empty = true;
while( rs.next() ) {
    // ResultSet processing here
    empty = false;
}

if( empty ) {
    // Empty result set
}