在Java语言中调用存储过程、存储函数、包头、包体

须要拷贝连接Oracle的jar包，路径例如以下图所看到的：

连接Oracle数据库的代码：

package demo.utils;

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:@192.168.56.101:1521:orcl";
	private static String user = "scott";
	private static String password = "tiger";
	static{
		try {
			Class.forName(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;
	}

	/*
	 * 执行Java程序
	 * java -Xms100M -Xmx200M HellWorld
	 * 
	 * 技术方向:
	 * 1. 性能调优
	 * 2. 故障诊断: 死锁
	 */
	public static void release(Connection conn,Statement st,ResultSet rs){
		if(rs != null){
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}finally{
				rs = null;//why? --> Java GC，让Java的垃圾回收器回收，我们是不能控制垃圾回收器的。即使我们调用了System.gc()，也是不能马上回收的，Java的垃圾回收器是不可控的。
			}
		}
		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;
			}
		}
	}
}

Java GC，让Java的垃圾回收器回收，我们是不能控制垃圾回收器的。即使我们调用了System.gc()。也是不能马上回收的，Java的垃圾回收器是不可控的。System.gc()仅仅是请求jvm回收。

測试的代码：

各自是在Java语言中调用存储过程、在Java语言中调用存储函数、在Java语言中调用包头和包体。

--查询某个员工的姓名 职位和月薪

/*
思考:
1. out參数太多???
2. 查询某个部门中全部员工的全部信息
*/
create or replace procedure queryEmpInfoma(eno in number,
                                         pename out varchar2,
                                         pjob   out varchar2,
                                         psal   out number)
as
begin
  select ename,empjob,sal into pename,pjob,psal from emp where empno=eno;

end;
/

--查询某个员工的年收入
create or replace function queryEmpIncome(eno in number)
return number
as
     --定义变量保存月薪和奖金
     psal emp.sal%type;
     pcomm emp.comm%type;
begin
     select sal,comm into psal,pcomm from emp where empno=eno;
     --返回年收入
     return psal*12+nvl(pcomm,0);
end;
/

declare 
	income number;
begin
	
	income:=queryEmpIncome(7369);
	dbms_output.put_line(income);
end;
/

查询某个部门中全部员工的全部信息


包头
CREATE OR REPLACE PACKAGE MYPACKAGE AS 

  type empcursor is ref cursor;
  procedure queryEmpList(dno in number,empList out empcursor);
END MYPACKAGE;


包体
CREATE OR REPLACE PACKAGE BODY MYPACKAGE AS

  procedure queryEmpList(dno in number,empList out empcursor) AS
  BEGIN

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

  END queryEmpList;

END MYPACKAGE;

package demo.oracle;

import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.ResultSet;

import oracle.jdbc.OracleCallableStatement;
import oracle.jdbc.OracleTypes;

import org.junit.Test;

import demo.utils.JDBCUtils;

/*
 * 思考 
 * 1. 光标close了吗?
关闭了。光标是通过call得到的，而call是通过conn得到的，所以conn关闭了。那么光标就关闭了
 * 2. 以下的代码能在mysql上运行吗？不能。实际和理论总是有区别的。
 */
public class TestOracle {
/*
 * create or replace procedure queryEmpInfo(eno in number,
                                         pename out varchar2,
                                         pjob   out varchar2,
                                         psal   out number)
 */
	@Test
	public void tesProcedure(){
		// {call <procedure-name>[(<arg1>,<arg2>, ...)]}
		String sql = "{call queryEmpInfoma(?,?
,?,?)}";
		Connection conn = null;
		CallableStatement call = null;
		try {
			conn = JDBCUtils.getConnection();
			call = conn.prepareCall(sql);
			
			//对于in參数，赋值
			call.setInt(1, 7839);
			
			//对于out參数，申明
			call.registerOutParameter(2, OracleTypes.VARCHAR);
			call.registerOutParameter(3, OracleTypes.VARCHAR);
			call.registerOutParameter(4, OracleTypes.NUMBER);
			
			//运行
			call.execute();
			
			//取出结果
			String name = call.getString(2);
			String job = call.getString(3);
			double sal = call.getDouble(4);
			System.out.println(name);
			System.out.println(job);
			System.out.println(sal);
		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			JDBCUtils.release(conn, call, null);
		}
	}

/*
 * create or replace function queryEmpIncome(eno in number)
return number	
 */
	@Test
	public void tesFunction(){
		//{?
= call <procedure-name>[(<arg1>,<arg2>, ...)]}
		String sql = "{?=call queryEmpIncome(?)}";
		Connection conn = null;
		CallableStatement call = null;
		try {
			conn = JDBCUtils.getConnection();
			call = conn.prepareCall(sql);
			
			//对于out參数，申明
			call.registerOutParameter(1, OracleTypes.NUMBER);
			
			//对于in參数，赋值
			call.setInt(2, 7839);
			
			//运行
			call.execute();
			
			//取出结果
			double income = call.getDouble(1);
			System.out.println(income);

		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			JDBCUtils.release(conn, call, null);
		}		
	}
	
	@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參数，赋值
			call.setInt(1,20);
			
			//对于out參数，申明
			call.registerOutParameter(2, OracleTypes.CURSOR);
			
			//运行
			call.execute();
			
			//取出结果
			rs = ((OracleCallableStatement)call).getCursor(2);
			while(rs.next()){
				String name = rs.getString("ename");
				String job = rs.getString("job");
				double sal = rs.getDouble("sal");
				
				System.out.println(name+"\t"+job+"\t"+sal);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			JDBCUtils.release(conn, call, rs);
		}	
	}
}