preparestatmentdemo.java

软通公司培训的课件和习题里面有答案。。。

package com.ten.jdbc;

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

public class PrepareStatmentDemo {

	private Connection conn = null ;
	private PreparedStatement pstmt = null ;
	private ResultSet rs = null ;
	
	private String url = "jdbc:oracle:thin:@127.0.0.1:1521:stan" ;
	private String username = "stan";
	private String password = "stan";
	private String sql = "" ;
	
	public PrepareStatmentDemo(){
		try{
			// 1 注册，加载Oacle驱动程序
			DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
			// 2 建立连接
			conn = DriverManager.getConnection(url,username,password);
			
		}catch(SQLException e){
			e.printStackTrace();
		}
	}
	
	public void updateEmpSalery(){
		sql = " update emp set sal=sal+? where empno = ?" ;  
		try {
			 // 3 创建 Statement 对象,预编译sql语句
			pstmt = conn.prepareStatement(sql);
			
			// 4 sql赋值
			pstmt.setInt(1, 1);     // 为第一个参数(?)赋值 1
			pstmt.setInt(2, 7369);  // 为第二个参数(?)赋值 7369
			
			// 5 执行更改
			pstmt.executeUpdate();
			
		} catch (SQLException e) {
			 
			e.printStackTrace();
		}	
	}
	
	public void closeConn(){
		try{
			if(rs!=null){
				this.conn.close();
			}	
			if(pstmt!=null){
				this.pstmt.close();
			}
			if(conn!=null){
				this.conn.close();
			}
		}catch(SQLException e){
			e.printStackTrace();
		}

	}
	
	
	public static void main(String[] args) {
		PrepareStatmentDemo ps = new PrepareStatmentDemo();
		ps.updateEmpSalery();
		ps.closeConn();
	}

}