如何在Oracle中将表作为输出参数获取

Question

我正在尝试将Oracle过程调用的输出参数转换为对象。由于我需要定义一个映射来告诉方法如何进行转换，所以它无法正常工作。如果映射为空或未正确填充，则默认为类型为STRUCT的对象 - 在我的情况下是错误的。

我建立了一个示例，应该说明这个问题：

-- Procedure in database
PROCEDURE myprocedure (
inputParam                IN       VARCHAR2 (4),
outputOne                 OUT outputOneSQLType
outputTwo                 OUT outputTwoSQLType);

-- inside of a package
inside a package mypackage

-- first type
create or replace
TYPE outputOneSQLType IS TABLE OF tableOneExample

-- table of type
create or replace
TYPE tableOneExample AS OBJECT (
      somethingOne                 VARCHAR2 (4)
     ,somethingTwo        NUMBER (12)
)

//java from here

import oracle.jdbc.OracleCallableStatement;
import oracle.jdbc.OracleTypes;
import oracle.jdbc.oracore.OracleTypeADT;
import oracle.sql.STRUCT;
...
oracle.jdbc.driver.OracleConnection oracleConn = (oracle.jdbc.driver.OracleConnection) con.getMetaData().getConnection();
final OracleCallableStatement storedProc = (OracleCallableStatement)oracleConn.prepareCall("{call mypackage.myprocedure("+
                ":inputParam, :outputOne, :outputTwo)}");

storedProc.setString("inputParam", "SomeValue");

storedProc.registerOutParameter("outputOne",  OracleTypes.STRUCT, "OUTPUTONESQLTYPE");
storedProc.registerOutParameter("outputTwo",  OracleTypes.STRUCT, "OUTPUTTWOSQLTYPE");

storedProc.execute();

//So far so good

//now I am lost - I need to define the map to get the object? 
//What should be inside the map?
Hashtable newMap = new Hashtable();

newMap.put("outputOneSQLType", ?????.class);

//If the map is empty, it defaults to STRUCT...
final STRUCT myObject =  (STRUCT)storedProc.getObject("somethingOne",newMap);
// myObject.getBytes() gives me an object... but I cannot cast it to anything

由于错误的地图，我无法使用类似以下内容的功能：

final MyClass myObject =  (MyClass)storedProc.getObject("somethingOne",newMap);   

如何填写地图？

编辑 1

无法更改 Oracle 数据库中的条目。我只允许使用它们。因此，

stmt.registerOutParameter(2, java.sql.Types.ARRAY, "OUTPUTONESQLTYPE"); 

无法工作。因为一旦我不使用“OracleTypes.STRUCT”，就会抛出异常。看起来在outputOneSQLType中有一个类型为“OracleTypeCOLLECTION”的对象。

当我尝试使用

 Hashtable newMap = new Hashtable();
newMap.put("outputOneSQLType",OracleTypeCOLLECTION.class);
final OracleTypeCOLLECTION myObject =  (OracleTypeCOLLECTION)storedProc.getObject("somethingOne",newMap);

我遇到了一个异常：InstantiationException: oracle.jdbc.oracore.OracleTypeCOLLECTION @DazzaL：我会尝试定义一个SQLDATA接口，也许那就是解决方案。 解决方案：

1. 准备语句应该类似于"begin package.procedure(...); end;"而不是"{call package.procedure(...)})"
2. 需要一个SQLData接口。

@DazzaL：你太棒了！谢谢。

- M.R.

Answer 1

你需要定义一个sqldata对象来映射这个。

文档：http://docs.oracle.com/cd/E11882_01/java.112/e16548/oraarr.htm#JJDBC28574

例如：

SQL> create or replace TYPE tableOneExample AS OBJECT (
  2        somethingOne                 VARCHAR2 (4)
  3       ,somethingTwo        NUMBER (12)
  4  );
  5  /

Type created.

SQL> create or replace TYPE outputOneSQLType IS TABLE OF tableOneExample;
  2  /

Type created.

SQL>
SQL> create or replace PROCEDURE myprocedure (
  2  inputParam                IN       VARCHAR2,
  3  outputOne                 OUT outputOneSQLType)
  4  as
  5  begin
  6  outputOne  := outputOneSQLType(tableOneExample('a', 1), tableOneExample('b', 2));
  7  end;
  8  /

Procedure created.

现在我们定义SQLDATA接口：

import java.sql.*;

public class TestArr implements SQLData
 {
  private String sql_type;

  public String attrOne;
  public int    attrTwo;

  public TestArr() 
  { 
  }
  public TestArr (String sql_type, String attrOne, int attrTwo)
  {
    this.sql_type = sql_type;
    this.attrOne = attrOne;
    this.attrTwo = attrTwo;
   }

  // define a get method to return the SQL type of the object
  public String getSQLTypeName() throws SQLException
  { 
    return sql_type; 
  } 

  // define the required readSQL() method 
  public void readSQL(SQLInput stream, String typeName)
    throws SQLException
  {
    sql_type = typeName;

    attrOne = stream.readString();
    attrTwo = stream.readInt();
  }  
  // define the required writeSQL() method 
  public void writeSQL(SQLOutput stream)
    throws SQLException
  { 
    stream.writeString(attrOne);
    stream.writeInt(attrTwo);
  }
}

确保流写入/读取的输入和顺序与您的Oracle类型相同，任何不一致都会导致内部表示错误。

然后，在主类中，您需要按以下方式进行映射：

CallableStatement stmt = conn.prepareCall("begin myprocedure(?,?); end;");
stmt.setString(1, "foo");
stmt.registerOutParameter(2, java.sql.Types.ARRAY, "OUTPUTONESQLTYPE"); // YOUR ARRAY TYPE (TO MATCH THE API OUTPUT), NOT OBJECT
stmt.execute();
Array arr = stmt.getArray (2);
Map map = conn.getTypeMap();
map.put("TABLEONEEXAMPLE", Class.forName("TestArr")); // YOUR OBJECT TYPE, NOT ARRAY.
Object[] values = (Object[]) arr.getArray();
for (int i=0; i < values.length; i++)
{
  TestArr a = (TestArr)values[i];
  System.out.println("somethingOne: " + a.attrOne);
  System.out.println("somethingTwo: " + a.attrTwo);
}

结果为：

M:\Documents\Sample Code\1>javac TestArr.java

M:\Documents\Sample Code\1>javac ArrayTest.java
Note: ArrayTest.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

M:\Documents\Sample Code\SQLComplexArray>java ArrayTest
Opening Oracle connection...done.
somethingOne: a
somethingTwo: 1
somethingOne: b
somethingTwo: 2

- DazzaL

---

谢谢。我会尝试定义一个SQLDATA接口，也许那就是解决方案。 - M.R.

太棒了，谢谢！我希望我能再加10分。 - spiderman

对我很有用，我也发布了我的帖子 - http://stackoverflow.com/questions/25253448/java-plsql-call-table-of-records-from-java/25274486#25274486 - spiderman