一.JDBC连接数据库


package com.vetor;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
/*
 * 1.数据库的名称
 * 2.*/
public class JDBC {
	public static void main(String[] args) {
		Statement stmt = null;
		ResultSet rs = null;
		Connection conn = null;
		try {
			//1.注册数据库驱动
			Class.forName("com.mysql.jdbc.Driver");
			//2.通过DriverManager获取数据库连接
			String url = "jdbc:mysql://localhost:3307/student";
			String username = "root";
			String password = "root";
		    conn = DriverManager.getConnection(url,username,password);
			//3.通过Connection对象获取Statement对象
		    stmt = conn.createStatement();
		    //4.使用Statement执行SQL语句
		    String sql = "update student set age=20 where age=18";
		    // rs = stmt.executeQuery(sql);
		    int  n = stmt.executeUpdate(sql);
		    //5.操作结果集
		    /*
		    String sql = "select * from student";
		    rs = stmt.executeQuery(sql);
		    System.out.println("sno"+"\t"+"sname"+"\t"+"sex"+"\t"+ "age"+"\t"+"sclass"+"\t");
		    while(rs.next()) {  //读一行
		    	String sno = rs.getString(1);
		    	//通过列名获取指定字段的值
		    	String sname = rs.getString("sname");
		    	String sex = rs.getString("sex");
		    	int age = rs.getInt("age");
		    	int sclass = rs.getInt(5);
		    	System.out.println(sno+"\t"+sname+"\t"+sex+"\t"+age+"\t"+sclass+"\t");
		    	
		    			
		    }
		    */
		    System.out.println("更新影响的行数是: " +n);
		    
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			//6.回收数据资源
			if(rs!=null) {
				try {
					rs.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if(stmt!=null) {
				try {
					stmt.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if(conn!=null) {
				try {
					conn.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
		
	}

}