JavaWeb使用JDBC增加删除修改查询数据库内容：
数据库：
自行建库建表，主键 id
后端：
新建项目模块
选择模块，添加依赖
配置文件：
db.properties
driver=com.mysql.cj.jdbc.Driver
user=root
url=jdbc:mysql://127.0.0.1:3306/csdn
password=ROOT
Java类：
add增加
package com.swc;
import java.sql.*;
import java.util.ResourceBundle;
public class add {
// main
public static void main(String[] args) {
//ctrl alt l
//读取属性配置文件
ResourceBundle bundle = ResourceBundle.getBundle("com/swc/resources/db");
// ctrl alt v
String driver = bundle.getString("driver");
String user = bundle.getString("user");
String password = bundle.getString("password");
String url = bundle.getString("url");
// 放大 变量 作用域
Connection con = null;
Statement st = null;
ResultSet rs = null;
//注册驱动
try {
Class.forName(driver);
//类名调用 静态方法
//alt enter
//获取连接对象
con = DriverManager.getConnection(url, user, password);
//操作
st = con.createStatement();
//写sql语句
String sql = "insert into pthree_jdbc(user,password) values('用户1','123456')"; //增
//执行
st.execute(sql);
} catch (ClassNotFoundException | SQLException e) {
e.printStackTrace();
//关闭
} finally {
//rs st con
if (rs != null) {
try {
rs.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
if (st != null) {
try {
st.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
if (con != null) {
try {
con.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
}
}
}
- 运行add.java文件
- 数据库增加数据
modify修改
package com.swc;
import java.sql.*;
import java.util.ResourceBundle;
public class modify {
// main
public static void main(String[] args) {
//ctrl alt l
//读取属性配置文件
ResourceBundle bundle = ResourceBundle.getBundle("com/swc/resources/db");
// ctrl alt v
String driver = bundle.getString("driver");
String user = bundle.getString("user");
String password = bundle.getString("password");
String url = bundle.getString("url");
//ctrl+d 复制当前行到下一行
// 放大 变量 作用域
Connection con = null;
Statement st = null;
ResultSet rs = null;
//注册驱动
try {
Class.forName(driver);
//类名调用 静态方法
//alt enter
//获取连接对象
con = DriverManager.getConnection(url, user, password);
//操作
st = con.createStatement();
//写sql语句
String sql = "update pthree_jdbc set user = '用户2' where id = 1"; //改
//执行
st.execute(sql);
} catch (ClassNotFoundException | SQLException e) {
e.printStackTrace();
//关闭
} finally {
//rs st con
if (rs != null) {
try {
rs.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
if (st != null) {
try {
st.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
if (con != null) {
try {
con.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
}
}
}
-
运行modify.java文件
-
数据库修改数据
query查询
package com.swc;
import java.sql.*;
import java.util.ResourceBundle;
public class query {
// main
public static void main(String[] args) {
//ctrl alt l
//读取属性配置文件
ResourceBundle bundle = ResourceBundle.getBundle("com/swc/resources/db");
// ctrl alt v
String driver = bundle.getString("driver");
String user = bundle.getString("user");
String password = bundle.getString("password");
String url = bundle.getString("url");
//ctrl+d 复制当前行到下一行
// 放大 变量 作用域
Connection con = null;
Statement st = null;
ResultSet rs = null;
//注册驱动
try {
Class.forName(driver);
//类名调用 静态方法
//alt enter
//获取连接对象
con = DriverManager.getConnection(url, user, password);
//操作
st = con.createStatement();
//写sql语句
String sql = "select * from pthree_jdbc"; //查
rs = st.executeQuery(sql);
while (rs.next()) {
System.out.println("id："+rs.getString(1));
System.out.println("user："+rs.getString(2));
System.out.println("password："+rs.getString(3));
} //查
//执行
st.execute(sql);
} catch (ClassNotFoundException | SQLException e) {
e.printStackTrace();
//关闭
} finally {
//rs st con
if (rs != null) {
try {
rs.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
if (st != null) {
try {
st.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
if (con != null) {
try {
con.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
}
}
}
-
运行query.java文件
-
-
控制台输出，查询到数据库内容
delete删除
package com.swc;
import java.sql.*;
import java.util.ResourceBundle;
public class delete {
// main
public static void main(String[] args) {
//ctrl alt l
//读取属性配置文件
ResourceBundle bundle = ResourceBundle.getBundle("com/swc/resources/db");
// ctrl alt v
String driver = bundle.getString("driver");
String user = bundle.getString("user");
String password = bundle.getString("password");
String url = bundle.getString("url");
//ctrl+d 复制当前行到下一行
// 放大 变量 作用域
Connection con = null;
Statement st = null;
ResultSet rs = null;
//注册驱动
try {
Class.forName(driver);
//类名调用 静态方法
//alt enter
//获取连接对象
con = DriverManager.getConnection(url, user, password);
//操作
st = con.createStatement();
//写sql语句
String sql = "delete from pthree_jdbc where user = '用户2'"; //删
//执行
st.execute(sql);
} catch (ClassNotFoundException | SQLException e) {
e.printStackTrace();
//关闭
} finally {
//rs st con
if (rs != null) {
try {
rs.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
if (st != null) {
try {
st.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
if (con != null) {
try {
con.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
}
}
}
-
运行delete.java文件
-
数据库删除数据
