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[英]How to insert a date from form to a column whose type is Datetime in database
[英]How to detect JSON column type from Database
有一些代碼可以將數據庫ResultSet轉換為JSON。 現在,它可以處理數字值和字符串,並且效果很好。 但是,當它獲取JSON值時,會在其上使用toString
,而不是將其視為JSON,這意味着提取時,它已轉義了雙引號等,並且無法重新序列化為JSON。
如何從PostgreSQL數據庫中檢測JSON列類型?
編輯:這是@ f1sh建議的解決方案。 @ f1sh,如果要提交評論作為答案,我會將其標記為已接受的解決方案。
private JsonNode resultSetToJson(ResultSet rs) throws SQLException {
ObjectNode node = DataFileTool.OBJECT_MAPPER.createObjectNode();
ResultSetMetaData mData = rs.getMetaData();
int columnCount = mData.getColumnCount();
for (int i = 1; i <= columnCount; i++) {
Object obj = rs.getObject(i);
String columnName = mData.getColumnLabel(i);
String columnNameToUse = dbColumnNameToJsonKey.containsKey(columnName)
? dbColumnNameToJsonKey.get(columnName) : columnName;
if (mData.getColumnType(i) == Types.NUMERIC) {
if (obj == null) {
node.putNull(columnNameToUse);
} else if (obj instanceof BigDecimal) {
node.put(columnNameToUse, (BigDecimal) obj);
} else if (obj instanceof Integer) {
node.put(columnNameToUse, (Integer) obj);
} else if (obj instanceof Double) {
node.put(columnNameToUse, (Double) obj);
} else if (obj instanceof Long) {
node.put(columnNameToUse, (Long) obj);
} else if (obj instanceof Float) {
node.put(columnNameToUse, (Float) obj);
} else if (obj instanceof Short) {
node.put(columnNameToUse, (Short) obj);
} else if (obj instanceof BigInteger) {
node.set(columnNameToUse, BigIntegerNode.valueOf((BigInteger) obj));
} else if (obj instanceof Byte) {
node.put(columnNameToUse, (Byte) obj);
} else {
node.put(columnNameToUse, obj.toString());
}
} else if (obj instanceof PGobject) {
PGobject pg = (PGobject) obj;
if (pg.getType().equalsIgnoreCase("json")) {
JsonNode pgNode;
try {
pgNode = DataFileTool.OBJECT_MAPPER.readTree(pg.getValue());
node.set(columnNameToUse, pgNode);
} catch (IOException e) {
LOGGER.error("An exception occurred while attempting to parse JSON PGObject to JsonNode: {}",
obj, e);
node.put(columnNameToUse, obj.toString());
}
} else {
node.put(columnNameToUse, obj.toString());
}
} else if (obj == null) {
node.put(columnNameToUse, StringUtils.EMPTY);
} else {
node.put(columnNameToUse, obj.toString());
}
}
return node;
}
if (obj instanceof PGobject) {
PGobject pg = (PGobject) obj;
if (pg.getType().equalsIgnoreCase("json")) {
JsonNode pgNode;
try {
pgNode = DataFileTool.OBJECT_MAPPER.readTree(pg.getValue());
node.set(columnNameToUse, pgNode);
} catch (IOException e) {
LOGGER.error("An exception occurred while attempting to parse JSON PGObject to JsonNode: {}",
obj, e);
node.put(columnNameToUse, obj.toString());
}
} else {
node.put(columnNameToUse, obj.toString());
}
}
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