Oracle对象-包头，包体返回游标 多参数值

前言

    在编写存储过程或存储函数的过程中，你可能会发现，当需要的返回值过多，就需要更多的变量来接受它。是否可能用一个光标来接受返回值？答案当然是可以的。在Oracle数据库中，可以定义包头和包体。包头相当于声明，而包体则是逻辑实现。

实例

包头声明如下：CREATE OR REPLACE PACKAGE MYPACKAGE AS 

  type empcursor is ref cursor;
  procedure queryEmpList(dno in number,empList out empcursor);--empcursor是上一条语句定义的类型。

END MYPACKAGE;包体声明如下：CREATE OR REPLACE PACKAGE BODY MYPACKAGE AS

procedure queryEmpList(dno in number,empList out empcursor) AS--这里用来声明包体
BEGIN

open empList for select * from emp where deptno=dno;

END queryEmpList;

END MYPACKAGE;

Java调用

@Test
public void testCursor(){
String sql = "{call MYPACKAGE.QUERYEMPLIST(?,?)}";
Connection conn = null;
CallableStatement call = null;
ResultSet rs = null;
try {
conn = JDBCUtils.getConnection();
call = conn.prepareCall(sql);

//对于in参数，赋值
call.setInt(1, 20);

//对于out参数，申明
call.registerOutParameter(2, OracleTypes.CURSOR);

//执行
call.execute();

//取出结果
rs = ((OracleCallableStatement)call).getCursor(2);
while(rs.next()){
String name = rs.getString("ename");
double sal = rs.getDouble("sal");
String job = rs.getString("job");
System.out.println(name+"\t"+sal+"\t"+job);
}
} catch (Exception e) {
e.printStackTrace();
}finally{
JDBCUtils.release(conn, call, rs);
}

}
}

package demo;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class JDBCUtils {

private static String driver = "oracle.jdbc.OracleDriver";
private static String url = "jdbc:oracle:thin:@192.168.137.129:1521/orcl";
private static String user = "scott";
private static String password = "tiger";

static{
//注册驱动
try {
Class.forName(driver);
//DriverManager.registerDriver(driver);
} catch (ClassNotFoundException e) {
throw new ExceptionInInitializerError(e);
}
}

public static Connection getConnection(){
try {
return DriverManager.getConnection(url, user, password);
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}

/*
* 运行Java程序：
* java -Xms100M -Xmx200M HelloWorld
*
* 技术方向：
* 1. 性能优化
* 2. 故障诊断:死锁 ThreadDump
*/
public static void release(Connection conn,Statement st,ResultSet rs){
if(rs != null){
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}finally{
rs = null;//-----> Java GC
}
}
if(st != null){
try {
st.close();
} catch (SQLException e) {
e.printStackTrace();
}finally{
st = null;
}
}
if(conn != null){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}finally{
conn = null;
}
}
}
}