java - 在 java 中重用 PrepareStatement 中的参数

Question

private String QUERY = "(SELECT * FROM tab1 WHERE year = ? and month = ?) UNION (SELECT * FROM tab2 WHERE year = ? and month = ?) UNION (SELECT * FROM tab3 WHERE year = ? and month = ?");

aPreparedStatement = connection.prepareStatement(QUERY);
aPreparedStatement.setString(1, "2012");
aPreparedStatement.setString(2, "july");
aPreparedStatement.setString(3, "2012");
aPreparedStatement.setString(4, "2012");
aPreparedStatement.setString(5, "july");
aPreparedStatement.setString(6, "2012");

而不是一次又一次地为“？”设置相同的参数，有什么方法可以避免使用多个 setString 方法来替换 PreparedStatement 中的相同参数？

Answer 1

你可以设计一个辅助方法，像这样:

void setString(PreparedStatement pstmt, String s, Integer... indices) {
    for (Integer index : indices) {
        pstmt.setString(index, s);
    }
}

然后调用:

setString(aPreparedStatement, "2012", 1, 3, 4, 6);
setString(aPreparedStatement, "july", 2, 5);