我在java代码中使用mariadb中的resultset更新列值时遇到问题。看起来像mariadb JDBC连接器中不支持resultset.updateString()方法,任何人都可以给我发送替代方法来执行此过程。
MariaDB连接器版本:mariadb-java-client-1.5.8.jar, MariaDB版本:mariadb-10.1.20-winx64
以下是代码段: Java Code Snippet
抛出异常: Exception Trace
答案 0 :(得分:1)
您可以使用Statement.executeUpdate()代替。
因此,您还需要将SELECT
语句更改为UPDATE语句。
缺点是您无法访问单行数据,因为您根本不会选择它。如果你需要这个,例如要计算更新后的值(在您的情况下为test@<localipaddress>
),您可能必须先按照您的选择启动选择,在内存中计算更新,然后使用PreparedStatement或Batch Update执行相应的操作UPDATE
陈述。
准备好的陈述示例:
public static int preparedUpdate(Connection conn, String localIPAddress) throws SQLException {
int numChangedRows = 0;
try (Statement stmt = conn.createStatement()) {
ResultSet rs = stmt.executeQuery("SELECT * FROM table1");
while (rs.next()) {
// id => something unique for this row within the table,
// typically the primary key
String id = rs.getString("id");
String jid = rs.getString("column1");
if("abc".equals(jid)) { // just some nonsense condition
try (PreparedStatement batchUpdate = conn.prepareStatement("UPDATE table1 SET column1 = ? where id = ?")) {
batchUpdate.setString(1, localIPAddress);
batchUpdate.setString(2, id);
numChangedRows = batchUpdate.executeUpdate();
}
}
}
}
return numChangedRows;
}
批量更新示例:
public static int[] batchUpdate(Connection conn, String localIPAddress) throws SQLException {
int[] changedRows = null;
try (PreparedStatement batchUpdate = conn.prepareStatement("UPDATE table1 SET column1 = ? where id = ?")) {
try (Statement stmt = conn.createStatement()) {
ResultSet rs = stmt.executeQuery("SELECT * FROM table1");
while (rs.next()) {
// id => something unique for this row within the table,
// typically the primary key
String id = rs.getString("id");
String jid = rs.getString("column1");
if("abc".equals(jid)) { // just some nonsense condition
batchUpdate.setString(1, localIPAddress);
batchUpdate.setString(2, id);
batchUpdate.addBatch();
}
}
}
changedRows = batchUpdate.executeBatch();
}
return changedRows;
}