如何将java.sql.Array写入Oracle的SQLData.writeSQL()中的java.sql.SQLOutput

Question

我已实现java.sql.SQLData为了使用ojdbc6将UDT对象绑定到预准备语句.现在,我的一些UDT包含数组.我现在需要做的是:

class MyType implements SQLData {
  public void writeSQL(SQLOutput stream) throws SQLException {
    Array array = //...
    stream.writeArray(array);
  }
}

为了构建Oracle数组,我需要一个JDBC连接.通常,这样做是这样的:

OracleConnection conn = // ...
Array array = conn.createARRAY("MY_ARRAY_TYPE", new Integer[] { 1, 2, 3 });

但是,在那种writeSQL(SQLOutput)方法中,我没有连接.此外,由于在简明问题中难以解释的原因,我无法维护连接参考MyType.我可以以某种方式从中提取该连接SQLOutput吗？我想避免使用像这样的不稳定结构:

// In ojdbc6, I have observed a private "conn" member in OracleSQLOutput:
Field field = stream.getClass().getDeclaredField("conn");
field.setAccessible(true);
OracleConnection conn = (OracleConnection) field.get(stream);

有任何想法吗？备择方案？

Answer 1

这是我为解决这个问题所做的工作.它不漂亮,但它的工作原理.

我在我的类实现SQLData中添加了一个方法,它接收java.sql.Connection并设置相应的java.sql.ARRAY对象.

像这样的东西:

public class MyObject01 implements SQLData {
   private String value;
   private MyObject02[] details; // do note that details is a java array
   // ... also added getters and setters for these two properties

   private Array detailsArray;

   public void setupArrays(oracle.jdbc.OracleConnection oconn)
      throws SQLException
   {
       detailsArrays = oconn.createARRAY(MyObject02.ORACLE_OBJECT_ARRAY_NAME, getDetails());
       // MyObject02.ORACLE_OBJECT_ARRAY_NAME must be the name of the oracle "table of" type name
       // Also note that in Oracle you can't use JDBC's default createArray
       // since it's not supported. That's why you need to get a OracleConnection
       // instance here. 
   }       

   @Override
   public void writeSQL(Stream stream) throws SQLException {
       stream.writeString(getValue());
       stream.writeArray(detailsArray); // that's it
   }

   @Override
   public void readSQL(Stream stream) throws SQLException {
       setValue(stream.readString());
       Array array = stream.readArray();
       if (array != null) {
           setDetails((MyObject02[])array.getArray());
       }
   }

这是第一部分.

然后,在过程调用中使用该对象之前,调用setupArrays 该对象的方法.例:

public class DB {
    public static String executeProc(Connection conn, MyObject01 obj)
        throws SQLException
    {
        CalllableStatement cs = conn.prepareCall(" { ? = call sch.proc(?) }");
        cs.registerOutParameter(1, Types.VARCHAR);
        obj.setupArrays((oracle.jdbc.Connection)conn);
        cs.setObject(2, obj, Types.STRUCT);
        cs.executeUpdate();
        String ret = cs.getString(1);
        cs.close();
        return ret;
    }
}

当然,在连接时,您需要正确注册您的类型:

Connection conn = DriverManager.getConnection("jdbc:oracle://localhost:1521/XE", "scott", "tiger" );
conn.getTypeMap().put(MyObject01.ORACLE_OBJECT_NAME, MyObject01.class);
conn.getTypeMap().put(MyObject02.ORACLE_OBJECT_NAME, MyObject02.class);
conn.getTypeMap().put(MyObject02.ORACLE_OBJECT_ARRAY_NAME, MyObject02[].class);

希望能帮助到你.