java操作mysql数据库

发布网友发布时间：2022-04-07 19:00

共3个回答

懂视网时间：2022-04-07 23:21

 把mysql与java连接的jar（mysql-connector-java-5.1.6-bin.jar）包导入工程.
package com.cn.edu;
 
 import java.beans.Statement; 
 import java.sql.Connection; 
 import java.sql.DriverManager; 
 import java.sql.PreparedStatement; 
 import java.sql.ResultSet; 
 import java.sql.SQLException; 
 
 public class helloworld { 
 private Connection conn = null; 
 PreparedStatement statement = null; 
 
 // connect to MySQL 
 void connSQL() { 
  String url = "jdbc:mysql://localhost:3306/hello?characterEncoding=UTF-8"; 
  String username = "root"; 
  String password = "root"; // 加载驱动程序以连接数据库 
  try { 
  Class.forName("com.mysql.jdbc.Driver" ); 
  conn = DriverManager.getConnection( url,username, password ); 
  } 
  //捕获加载驱动程序异常 
  catch ( ClassNotFoundException cnfex ) { 
   System.err.println( 
   "装载 JDBC/ODBC 驱动程序失败。" ); 
   cnfex.printStackTrace(); 
  } 
  //捕获连接数据库异常 
  catch ( SQLException sqlex ) { 
   System.err.println( "无法连接数据库" ); 
   sqlex.printStackTrace(); 
  } 
 } 
 
 // disconnect to MySQL 
 void deconnSQL() { 
  try { 
  if (conn != null) 
   conn.close(); 
  } catch (Exception e) { 
  System.out.println("关闭数据库问题 ："); 
  e.printStackTrace(); 
  } 
 } 
 
 // execute selection language 
 ResultSet selectSQL(String sql) { 
  ResultSet rs = null; 
  try { 
  statement = conn.prepareStatement(sql); 
  rs = statement.executeQuery(sql); 
  } catch (SQLException e) { 
  e.printStackTrace(); 
  } 
  return rs; 
 } 
 
 // execute insertion language 
 boolean insertSQL(String sql) { 
  try { 
  statement = conn.prepareStatement(sql); 
  statement.executeUpdate(); 
  return true; 
  } catch (SQLException e) { 
  System.out.println("插入数据库时出错："); 
  e.printStackTrace(); 
  } catch (Exception e) { 
  System.out.println("插入时出错："); 
  e.printStackTrace(); 
  } 
  return false; 
 } 
 //execute delete language 
 boolean deleteSQL(String sql) { 
  try { 
  statement = conn.prepareStatement(sql); 
  statement.executeUpdate(); 
  return true; 
  } catch (SQLException e) { 
  System.out.println("插入数据库时出错："); 
  e.printStackTrace(); 
  } catch (Exception e) { 
  System.out.println("插入时出错："); 
  e.printStackTrace(); 
  } 
  return false; 
 } 
 //execute update language 
 boolean updateSQL(String sql) { 
  try { 
  statement = conn.prepareStatement(sql); 
  statement.executeUpdate(); 
  return true; 
  } catch (SQLException e) { 
  System.out.println("插入数据库时出错："); 
  e.printStackTrace(); 
  } catch (Exception e) { 
  System.out.println("插入时出错："); 
  e.printStackTrace(); 
  } 
  return false; 
 } 
 // show data in ju_users 
 void layoutStyle2(ResultSet rs) { 
  System.out.println("-----------------"); 
  System.out.println("执行结果如下所示:"); 
  System.out.println("-----------------"); 
  System.out.println(" 用户ID" + "/t/t" + "淘宝ID" + "/t/t" + "用户名"+ "/t/t" + "密码"); 
  System.out.println("-----------------"); 
  try { 
  while (rs.next()) { 
   System.out.println(rs.getInt("ju_userID") + "/t/t" 
    + rs.getString("taobaoID") + "/t/t" 
    + rs.getString("ju_userName") 
    + "/t/t"+ rs.getString("ju_userPWD")); 
  } 
  } catch (SQLException e) { 
  System.out.println("显示时数据库出错。"); 
  e.printStackTrace(); 
  } catch (Exception e) { 
  System.out.println("显示出错。"); 
  e.printStackTrace(); 
  } 
 } 
 
 public static void main(String args[]) { 
 
  helloworld h = new helloworld(); 
  h.connSQL(); 
  String s = "select * from ju_users"; 
 
  String insert = "insert into ju_users(ju_userID,TaobaoID,ju_userName,ju_userPWD) values("+8329+","+34243+",'mm','789')"; 
  String update = "update ju_users set ju_userPWD =123 where ju_userName= 'mm'"; 
  String delete = "delete from ju_users where ju_userName= 'mm'"; 
 
  if (h.insertSQL(insert) == true) { 
  System.out.println("insert successfully"); 
  ResultSet resultSet = h.selectSQL(s); 
  h.layoutStyle2(resultSet); 
  } 
  if (h.updateSQL(update) == true) { 
  System.out.println("update successfully"); 
  ResultSet resultSet = h.selectSQL(s); 
  h.layoutStyle2(resultSet); 
  } 
  if (h.insertSQL(delete) == true) { 
  System.out.println("delete successfully"); 
  ResultSet resultSet = h.selectSQL(s); 
  h.layoutStyle2(resultSet); 
  } 
  
  h.deconnSQL(); 
 } 
 }

技术分享

1、创建数据库

create databasecwq

2、连接数据库

use cwq

3、创建数据表

命令：create table <表名> ( <字段名1> <类型1> [,..<字段名n> <类型n>]);
建立一个名为Class的表

mysql> create table Class(
> id int(4) not null primary key auto_increment,
> name char(20) not null,
> sex int(4) not null default ‘0‘,
> degree double(16,2));

4、删除数据表

drop table cwq

第二次作业：MySQL数据库及Java操作MySQL数据库

标签：

热心网友时间：2022-04-07 20:29

String [][] strs = new String[3][5] ;
/* String[] s1 = {"0","我","一","三","二"};
String[] s2 = {"1","周","四","六","八"};
String[] s3 = {"2","是","五","七","九"};
strs[0] = s1;
strs[1] = s2;
strs[2] = s3;
把这个替换成从数据库读取数据赋给这个数组
*/

for(int i = 1;i<5;i++)
{
for(int j = 0;j<3;j++)
{

System.out.println(strs[j][i]);//把这个替换成插入数据库的语句

}追问没有普遍性啊

追答...什么叫普遍型....你要说数据库的行列换了就不能用了你需要把循环中的大小改成对应的数组长度就行了.

热心网友时间：2022-04-07 21:47

你可以一次插一个字段