如何使用相同的语句和结果集运行多个select查询？[副本]

Question

我正在尝试编写一个简单的Java web应用程序来从数据库中获取数据。我需要在不同的数据库表上运行几个select查询。

String queryOne = "select firstname from employees where empid = id";
String queryOne = "select title from books where bookid = bid";
String queryOne = "select auther from books where bookid = bid";

Connection connection = dataSource.getConnection();
Statement statement = connection.createStatement();
ResultSet rs1 = statement.executeQuery(queryOne);

while (rs1.nest()) {
String firstName = rs1.getString(1);
}
statement.close();
connection.close();

我只能用相同的语句运行一个查询。如何使用相同的语句执行多个查询？

Answer 1

您也许可以将所需的查询存储在数组中，然后在数组中进行迭代，如下所示：

Connection conn = dataSource.getConnection();
try {
  Statement stmt = conn.createStatement();
  try {
    for (String q : queries) {  //queries is an array containing the 3 queries
      ResultSet rset = statement.executeQuery(q);
      try {
        rset.getString(1);
      } finally {
        rset.close();
      }
    }
  } finally {
    stmt.close();
  }
} finally {
  conn.close();
}

附注。最好将Connection、ResultSet和Statement对象封闭在try...finally块中，以便确保每次都能够关闭（）它们。