数据库的增删改查操作

来源：互联网发布：a 算法原理编辑：程序博客网时间：2024/05/16 15:28
与之前的工具类放在同一个包下。
package com.weixuan.project;import java.sql.Connection;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;/** * 与数据库相关的增删改查操作 *  * @author 韦轩 *  */public class CRUD {public static void main(String[] args) {try {new CRUD().read();//new CRUD().create();new CRUD().update();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}// CREATE 从数据库读取操作,即查找static void create() throws SQLException {Connection conn = null;Statement st = null;ResultSet rs = null;try {conn = JdbcUtils.getConnection();st = conn.createStatement();String sql = "insert into mytable(username,age,sex,hobby,ID) values('weihang',20,'男','玩游戏',null)";int co = st.executeUpdate(sql);System.out.println("co = "+co);} finally {JdbcUtils.free(rs, st, conn);}}// read 从数据库读取操作,即查找static void read() throws SQLException {Connection conn = null;Statement st = null;ResultSet rs = null;try {conn = JdbcUtils.getConnection();st = conn.createStatement();rs = st.executeQuery("select * from mytable");while (rs.next()) {System.out.println(rs.getObject("ID") + "\t" + rs.getObject("username")+ "\t" + rs.getObject("sex"));}} finally {JdbcUtils.free(rs, st, conn);}}// update 从数据库读取操作,即查找static void update() throws SQLException {Connection conn = null;Statement st = null;ResultSet rs = null;try {conn = JdbcUtils.getConnection();st = conn.createStatement();String sql = "update mytable set age = age+10";int i = st.executeUpdate(sql);System.out.println("i = "+i);} finally {JdbcUtils.free(rs, st, conn);}}// delete 从数据库读取操作,即查找static void delete() throws SQLException {Connection conn = null;Statement st = null;ResultSet rs = null;try {conn = JdbcUtils.getConnection();st = conn.createStatement();String sql = "delete from mytable where age >42";int i = st.executeUpdate(sql);System.out.println("i = "+i);} finally {JdbcUtils.free(rs, st, conn);}}}
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