Oracle Java 存储函数 - ORA-00932：不一致的数据类型

Question

尝试调用 java 存储函数并取回 java 对象并将其转换为 oracle 类型。 这是一个 10g 的数据库，我们使用的是 Java 1.4.2。 （我知道升级就是答案，不幸的是我受限于这个环境。）

下面列出的代码和错误。

任何帮助将不胜感激。

TestMapping.java

public class TestMapping {
    public static TestObject getResponse(){
        TestObject testObject = new TestObject();
        testObject.setMyTestValue("TEST");

        return testObject;
    }
}

TestObject.java

import java.sql.SQLData;
import java.sql.SQLException;
import java.sql.SQLInput;
import java.sql.SQLOutput;

public class TestObject implements SQLData {
    private String myTestValue;

    private String sqlTypeName;
    public String getSQLTypeName() throws SQLException {
        return sqlTypeName;
    }

    public void readSQL(SQLInput stream, String typeName) throws SQLException {
        sqlTypeName = typeName;
        myTestValue = stream.readString();
    }

    public void writeSQL(SQLOutput stream) throws SQLException {
        stream.writeString(myTestValue);
    }

    public String getMyTestValue() {
        return myTestValue;
    }

    public void setMyTestValue(String myTestValue) {
        this.myTestValue = myTestValue;
    }
}

命令行：

javac TestObject.java
javac TestMapping.java
loadjava -user user/pass@server:1521:instance -t -r TestObject.class
loadjava -user user/pass@server:1521:instance -t -r TestMapping.class

Oracle 类型：

create or replace
type test_object  as object(
myTestValue  varchar2(50));

发布 Java 函数：

create or replace
FUNCTION test_mapping RETURN test_object
AS LANGUAGE JAVA
NAME 'TestMapping.getResponse() return TestObject';

要测试的匿名块：

set serveroutput on;
declare 
  response test_object; 
begin
  response := test_mapping();
  DBMS_OUTPUT.PUT_LINE('myTestValue : ' || response.myTestValue);
end;

错误：

Error report:
ORA-00932: inconsistent datatypes: expected a return value that is an instance of a user defined Java class convertible to an Oracle type got an object that could not be converted
ORA-06512: at "USER.TEST_MAPPING", line 1
ORA-06512: at line 4
00932. 00000 -  "inconsistent datatypes: expected %s got %s"
*Cause:
*Action:

Answer 1

您需要返回oracle.sql.STRUCT 的实例，而不是您的自定义Java 类型的实例。这在您的 Oracle 出版物中都是如此...

create or replace
FUNCTION test_mapping RETURN test_object
AS LANGUAGE JAVA
NAME 'TestMapping.getResponse() return oracle.sql.STRUCT';

...在 Java 类中...

public static oracle.sql.STRUCT getResponse(){ ...

要构建 getResponse() 必须返回的 STRUCT，您需要执行以下操作：

// This is the object you really want to pass back
TestObject result;

STRUCT oracleResult;
try{
  StructDescriptor resultStructDescriptor = StructDescriptor.createDescriptor("TEST_OBJECT", yourOracleConnection);

  Object[] attributes = {result.myTestValue};
  oracleResult = new STRUCT(resultStructDescriptor, yourOracleConnection, attributes);
} catch ( SQLException e ) {
    throw new RuntimeException(e);
}
return oracleResult;