java.sql.SQLException：Blob数据类型上的PreparedStatement.setObject上的无效列类型

Question

用blob创建了一个表

CREATE TABLE SUGGEST_DATA (
LOCALE VARCHAR2(20) NOT NULL,
DATA_COLLECTION blob,
UPDATED_ON TIMESTAMP,
PRIMARY KEY (LOCALE)
)

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使用以下代码将哈希表（键=字符串，值=字符串的ArrayList）插入上表。

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Java代码：

conn = getDBConnection();
stmt = conn.prepareStatement("INSERT INTO SUGGEST_DATA (LOCALE,DATA_COLLECTION,UPDATED_ON) VALUES (?, ?, ?)");
stmt.setString(1, locale);
stmt.setObject(2, data);//this is a java hashtable
stmt.setTimestamp(3, new Timestamp(System.currentTimeMillis()));
stmt.executeUpdate();

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它在“ stmt.setObject”上失败

java.sql.SQLException: Invalid column type
    at oracle.jdbc.driver.OraclePreparedStatement.setObjectCritical(OraclePreparedStatement.java:11256)
    at oracle.jdbc.driver.OraclePreparedStatement.setObjectInternal(OraclePreparedStatement.java:10605)
    at oracle.jdbc.driver.OraclePreparedStatement.setObjectInternal(OraclePreparedStatement.java:11665)
    at oracle.jdbc.driver.OraclePreparedStatement.setObject(OraclePreparedStatement.java:11631)
    at oracle.jdbc.driver.OraclePreparedStatementWrapper.setObject(OraclePreparedStatementWrapper.java:253)