这是一个从 blob 反序列化 java 对象的 oracle 11g java 存储函数的示例。作为免费奖励添加了一个 oracle java 存储过程的示例，以使用序列化的 java 对象更新 blob。
如果对象的类不是 java 内置的（如我的情况），您还需要在 oracle 数据库中发布它的源（包含所有依赖项）。
CREATE OR REPLACE JAVA SOURCE NAMED "ServiceParamsBLOBHandler" AS
import java.io.*;
import java.util.*;
public class ServiceParamsBLOBHandler {
private static Object deserialize(InputStream stream) throws Exception {
ObjectInputStream ois = new ObjectInputStream(stream);
try {
return ois.readObject();
} finally {
ois.close();
}
}
private static byte[] serialize(Object object) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(baos);
oos.writeObject(object);
oos.close();
return baos.toByteArray();
}
//@SuppressWarnings("unchecked")
private static List<Map<String, String>> getParams(oracle.sql.BLOB blob) throws Exception {
return (List<Map<String, String>>) deserialize(blob.getBinaryStream());
}
public static oracle.sql.BLOB updatedParamField(oracle.sql.BLOB blob, String paramName, String fieldName, String value)
throws Exception {
List<Map<String, String>> params = getParams(blob);
Map<String, String> param = getParam(params, paramName);
param.put(fieldName, value);
oracle.sql.BLOB res = oracle.sql.BLOB.createTemporary(blob.getOracleConnection(), true, oracle.sql.BLOB.DURATION_CALL);
res.setBytes(1, serialize(params));
return res;
}
public static void updateParamField(oracle.sql.BLOB[] blobs, String paramName, String fieldName, String value)
throws Exception {
oracle.sql.BLOB blob = blobs[0];
List<Map<String, String>> params = getParams(blob);
Map<String, String> param = getParam(params, paramName);
param.put(fieldName, value);
blob.truncate(0);
blob.setBytes(1, serialize(params));
}
private static Map<String, String> getParam(List<Map<String, String>> params, String name) {
for (Map<String, String> param : params) {
if (name.equals(param.get("name"))) {
return param;
}
}
return null;
}
public static String getParamField(oracle.sql.BLOB blob, String paramName, String fieldName) throws Exception {
Map<String, String> param = getParam(getParams(blob), paramName);
return param == null ? null : param.get(fieldName);
}
}
/
alter java source "ServiceParamsBLOBHandler" compile
--select * from SYS.USER_ERRORS
/
CREATE OR REPLACE function getServiceParamField(b IN BLOB, paramName IN VARCHAR2, fieldName IN VARCHAR2) RETURN VARCHAR2
as LANGUAGE JAVA NAME 'ServiceParamsBLOBHandler.getParamField(oracle.sql.BLOB, java.lang.String, java.lang.String) return String';
/
CREATE OR REPLACE function updatedServiceParamField(b IN BLOB, paramName IN VARCHAR2, fieldName IN VARCHAR2, value IN VARCHAR2) RETURN BLOB
as LANGUAGE JAVA NAME 'ServiceParamsBLOBHandler.updatedParamField(oracle.sql.BLOB, java.lang.String, java.lang.String, java.lang.String) return oracle.sql.BLOB';
/
CREATE OR REPLACE PROCEDURE updateServiceParamField(b IN OUT BLOB, paramName IN VARCHAR2, fieldName IN VARCHAR2, value IN VARCHAR2)
AS LANGUAGE JAVA NAME 'ServiceParamsBLOBHandler.updateParamField(oracle.sql.BLOB[], java.lang.String, java.lang.String, java.lang.String)';
/
-- oracle blob read usage example:
select getServiceParamField(byte_value, 'account', 'format') from entity_property where name='params';
-- oracle blob update with java stored function usage example:
update entity_property set byte_value=updatedServiceParamField(byte_value, 'account', 'format', '15')
where name='params' and entity_id = 123
-- oracle blob update with java stored procedure usage example:
BEGIN
FOR c IN (select byte_value from entity_property where name='params' and entity_id = 123 for update) LOOP
updateServiceParamField(c.byte_value, 'account', 'format', '13');
END LOOP;
END;
/
更新
相关案例的具体片段。
1) 满载对象
private static String getVariable(oracle.sql.BLOB blob, String name) throws Exception {
ObjectInputStream ois = new ObjectInputStream(blob.getBinaryStream());
try {
//noinspection unchecked
return ((HashMap<String, String>) ((StorageBean) ois.readObject()).variables).get(name);
} finally {
ois.close();
}
}
2) 部分场载荷
private static String getVariable(oracle.sql.BLOB blob, String name) throws Exception {
ObjectInputStream ois = new ObjectInputStream(blob.getBinaryStream());
try {
ois.skipBytes(variablesOffset);
//noinspection unchecked
return ((HashMap<String, String>) ois.readObject()).get(name);
} finally {
ois.close();
}
}
