java - 通过java执行pl sql block 的问题

Question

我用java编写了以下代码。

package demo;

import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Types;

public class Sample {

    private Connection c = null;

    public Sample()
    {
        try {
            c = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:XE", "system", "jboss");
            String plsql = ""+
            "declare"+
                    "x number;"+
            "begin "+
                    "select HEADCOUNT  FROM PROJECT where deptid=1;"+
            "end;";
            CallableStatement cs = c.prepareCall(plsql);
            //cs.registerOutParameter(0, Types.INTEGER);

            cs.execute();
            System.out.println("Result is "+cs.getInt(1));
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public static void main(String[] args) 
    {
        Sample z = new Sample();
    }
}

我只是想探索通过 java 执行 plsql block 的机制。上面只是简单的查询。在执行上面的java代码时，我得到错误为

java.sql.SQLException: Invalid SQL type: sqlKind = UNINITIALIZED
    at oracle.jdbc.driver.T4CCallableStatement.doOall8(T4CCallableStatement.java:75)
    at oracle.jdbc.driver.T4CCallableStatement.executeForRows(T4CCallableStatement.java:1043)
    at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1336)
    at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3613)
    at oracle.jdbc.driver.OraclePreparedStatement.execute(OraclePreparedStatement.java:3714)
    at oracle.jdbc.driver.OracleCallableStatement.execute(OracleCallableStatement.java:4755)
    at oracle.jdbc.driver.OraclePreparedStatementWrapper.execute(OraclePreparedStatementWrapper.java:1378)
    at demo.Sample.<init>(Sample.java:26)
    at demo.Sample.main(Sample.java:36)

让我知道在执行此类 pl/sql block 之前是否需要任何预先设置。

Answer 1

1)第一个问题是其他答案中提到的declarex...。
2)第二个问题是select HEADCOUNT FROM PROJECT where deptid=1;在plsql中此查询无效。应该是 select HEADCOUNT into x ...