网站建设有哪些功能模块,推广运营方案,辽宁建设厅证件查询网站,网站建站公司费用你是否还在为每次新建项目连接数据库而烦恼#xff1f;#xff1f;#xff1f;#xff08;教你一次代码#xff0c;简单完成每次连接#xff09; 1.建立maven项目
还没下载安装或者不会建立maven项目的可以看这里哦#xff1a;maven的下载安装与配置环境变量#xff0…你是否还在为每次新建项目连接数据库而烦恼教你一次代码简单完成每次连接 1.建立maven项目
还没下载安装或者不会建立maven项目的可以看这里哦maven的下载安装与配置环境变量全网最详细_明天更新的博客-CSDN博客
2.编写配置文件。 dependenciesdependencygroupIdjavax.servlet/groupIdartifactIdjavax.servlet-api/artifactIdversion4.0.1/versionscopeprovided/scope/dependencydependencygroupIdjavax.servlet.jsp/groupIdartifactIdjsp-api/artifactIdversion2.2/versionscopeprovided/scope/dependencydependencygroupIdjavax.servlet/groupIdartifactIdjstl/artifactIdversion1.2/version/dependency!-- com.mysql/mysql-connector-j --dependencygroupIdcom.mysql/groupIdartifactIdmysql-connector-j/artifactIdversion8.1.0/version/dependency/dependencies
3.在项目的src/main/resources文件下建立db.properties文件并写入一下代码。 db.drivercom.mysql.cj.jdbc.Driver
db.urljdbc:mysql:/book
db.usernameroot
db.password
4.编写工具类。
/** Copyright (c) 2020, 2023, All rights reserved.**/
package cn;import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.*;/*** pProject: jdbcUnitls - Untils/p* pPowered by scl On 2023-08-15 19:12:41/p* p描述p** author 孙臣龙 [1846080280qq.com]* version 1.0* since 17*/
public class Untils {private String driver;private String url;private String username;private String password;private Connection con;//初始化自动建立连接public Untils() {connect();}//初始化传参可以连接自定义数据库public Untils(String url, String username, String password) {this.url url;this.username username;this.password password;connect(url, username, password);}//建立连接默认数据库public void connect() {ClassUntils until Untils.class;InputStream db until.getClassLoader().getResourceAsStream(db.properties);Properties prop new Properties();try {prop.load(db);this.driver prop.getProperty(db.driver, com.mysql.cj.jdbc.Driver);Class.forName(this.driver);this.url prop.getProperty(db.url, jdbc:mysql:/mysql);this.username prop.getProperty(db.username, root);this.password prop.getProperty(db.password, );con DriverManager.getConnection(this.url, this.username, this.password);} catch (Exception e) {e.printStackTrace();}}//建立连接指定数据库public void connect(String url, String username, String password) {try {Class.forName(driver);con DriverManager.getConnection(url, username, password);} catch (Exception e) {e.printStackTrace();}}//获取版本号public String version() {String ver ;try {ver this.con.getMetaData().getDatabaseProductVersion();} catch (Exception e) {e.printStackTrace();}return ver;}//建立数据库public void creatdatabase(String dbname) {try {String sql create database if not exists dbname;PreparedStatement ps con.prepareStatement(sql);ps.execute();} catch (Exception e) {e.printStackTrace();}}//删除数据库public void deletedatabase(String dbname) {try {String sql drop database if exists dbname;PreparedStatement ps con.prepareStatement(sql);ps.execute();} catch (Exception e) {e.printStackTrace();}}//查看所有数据库(排除系统数据库)public SetString showdatabase() {SetString set new HashSet();try {String sql show databases;PreparedStatement ps con.prepareStatement(sql);ResultSet rs ps.executeQuery();SetString exclude new HashSet(List.of(information_schema, performance_schema, test, sys, mysql));while (rs.next()) {String database rs.getString(1);if (exclude.contains(database)) continue;set.add(rs.getString(1));}rs.close();ps.close();} catch (Exception e) {e.printStackTrace();}return set;}//查看指定数据库的所有表public ListString showtables(String dbname) {ListString list new ArrayList();try {String sql show tables ;if (dbname ! null dbname.length() 0) {sql show tables from dbname;}PreparedStatement ps con.prepareStatement(sql);ResultSet rs ps.executeQuery();while (rs.next()) {list.add(rs.getString(1));}ps.close();rs.close();} catch (Exception e) {e.printStackTrace();}return list;}//查看使用数据库的表public ListString showtables() {String dbname ;try {String sql select database();PreparedStatement ps con.prepareStatement(sql);ResultSet rs ps.executeQuery();if (rs.isBeforeFirst()) {rs.next();dbname rs.getString(1);}} catch (Exception e) {e.printStackTrace();}return showtables(dbname);}//关闭连接public void close() {try {con.close();} catch (Exception e) {e.printStackTrace();}}public String getDriver() {return driver;}public void setDriver(String driver) {this.driver driver;}public String getUrl() {return url;}public void setUrl(String url) {this.url url;}public String getUsername() {return username;}public void setUsername(String username) {this.username username;}public String getPassword() {return password;}public void setPassword(String password) {this.password password;}public Connection getCon() {return con;}public void setCon(Connection con) {this.con con;}
}
5.将你写好的项目进行打包。
不会打包的可以作为参考maven如何打包你会吗_明天更新的博客-CSDN博客 6.将打包文件复制到常用架包文件夹中。 7.使用架包一行代码连接数据库 有小伙伴就有疑问啦 这就结束了多少是有点简单了
后续功能你可以根据自己所学进行添加。
