有一些代码可以将数据库结果集转换为 JSON。现在,它处理数值和字符串,并且工作得很好。但是,当它得到一个JSON值时,它在上面使用了toString
,而不是把它当成JSON处理,这意味着在提取时,它已经转义了双引号等,无法重新序列化成JSON.
如何从 PostgreSQL 数据库中检测 JSON 列类型?
编辑:这是@f1sh 所建议的解决方案。 @f1sh,如果您想提交您的评论作为答案,我会将其标记为已接受的解决方案。
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;
}
最佳答案
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());
}
}
关于java - 如何从数据库中检测 JSON 列类型,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/35180180/