初始配置:电脑安装oracle 11g(这里也可使是其它版本也可,此教程演示为11g),java环境,eclipse,oracle关于jdbc的jar包。
一,在scott用户下首先要有存储过程和存储方法
create or replace queryEmpIncome(eno in number) return number
as psal emp.sal%type; pcomm emp.comm%type; begin
select sal,comm into pasl,pcomm from emp where empno = eno;
return psal*12 + nvl(pcomm,0);
end;
create or replace procedure queryEmpInformation(eno in number,
pename out varchar2,psal out number,pjob out varchar2)
as
begin
select ename,sal,job into pename,psal,pjob from emp where empno = eno;
end;
二.创建数据库连接工具类
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:@localhost:1521:orcl";
private static String user = "scott";
private static String password = "tiger";
static{
//注册驱动
//DriverManager.registerDriver(driver)
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;
}
/*
* 运行Java:
* java -Xms100M -Xmx200M HelloWorld
*
* 技术方向:
* 1、性能优化
* 2、故障诊断:死锁(JDK: ThreadDump)
* Oracle: 自动处理
*/
public static void release(Connection conn,Statement st,ResultSet rs){
if(rs != null){
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}finally{
rs = null; ///-----> 原因:Java GC: Java的GC不受代码的控制
}
}
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;
}
}
}
}
三.写测试类
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 cn.ht.utils.JDBCUtils; public class TestOracle {
/*
* create or replace procedure queryEmpInformation(eno in number,
pename out varchar2,
psal out number,
pjob out varchar2)
*/
@Test
public void testProcedure(){
//{call <procedure-name>[(<arg1>,<arg2>, ...)]}
String sql = "{call queryEmpInformation(?,?,?,?)}";
Connection conn = null;
CallableStatement call = null;
try {
conn = JDBCUtils.getConnection();
call = conn.prepareCall(sql);
//对于in参数,赋值
call.setInt(1,7839);
//对于out参数,申明
call.registerOutParameter(2, OracleTypes.VARCHAR);
call.registerOutParameter(3, OracleTypes.NUMBER);
call.registerOutParameter(4, OracleTypes.VARCHAR);
//执行
call.execute();
//输出
String name = call.getString(2);
double sal = call.getDouble(3);
String job = call.getString(4);
System.out.println(name+"\t"+sal+"\t"+job);
} catch (Exception e) {
e.printStackTrace();
}finally{
JDBCUtils.release(conn, call, null);
}
} /*
* create or replace function queryEmpIncome(eno in number)
return number
*/
@Test
public void testFunction(){
//{?= call <procedure-name>[(<arg1>,<arg2>, ...)]}
String sql = "{?=call queryEmpIncome(?)}"; Connection conn = null;
CallableStatement call = null;
try {
conn = JDBCUtils.getConnection();
call = conn.prepareCall(sql); call.registerOutParameter(1, OracleTypes.NUMBER);
call.setInt(2, 7839); //执行
call.execute(); //取出年收入
double income = call.getDouble(1); System.out.println(income);
} catch (Exception e) {
e.printStackTrace();
}finally{
JDBCUtils.release(conn, call, null);
}
}
}
总结:以jdbc的方式实现了java查询数据库。并且调用了oracle的存储方法和过程。