Oracle JDBC自定义集合类型和SQLOutput writeString

Question

我在Oracle DB中创建了一个类型：

 create or replace TYPE client_type AS OBJECT
  ( 
  NMB NUMBER(7,0), 
  TITLE VARCHAR2(30),
  );

之后我用Java创建了一个相应的类;

public class Client implements SQLData {

    private int nmb;  
    private String title;

    public int getNmb() {
        return ncst;
    }
    public void setNmb(int nmb) {
        this.nmb = nmb;
    }
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }

    @Override
    public String getSQLTypeName() throws SQLException {
        return "CLIENT_TYPE";
    }
    @Override
    public void readSQL(SQLInput stream, String typeName) throws SQLException {
         setNmb(stream.readInt());
         setTitle(stream.readString());
    }
    @Override
    public void writeSQL(SQLOutput stream) throws SQLException {
        stream.writeInt(getNmb());
        stream.writeString(getTitle());
    }
}

然后我调用一个过程来插入新数据：

SimpleJdbcCall jdbcCall = new SimpleJdbcCall(jdbcTemplate).withProcedureName("P_INSERTCLIENT");
jdbcCall.declareParameters(new SqlParameter("P_CLIENT", OracleTypes.STRUCT, "CLIENT_TYPE"));
Map in = Collections.singletonMap("P_CLIENT", customer);                    
jdbcCall.execute(in);

NMB插入表中，TITLE值设置为null ... 我试图更改我的client_type，添加了一个DATE，它也被正确插入。

我在使用字符串做错了什么 - ＆gt; varchar字段？