java实现mysql数据库增删改查

本文将介绍java实现数据库增删改查的操作方法定义的代码，包括statment和preparestatment两种模式，两种的区别可以参考别的文章，按需选用。

例：getdata是statment的查询的方法，pgetdata是preparestatment的查询的方法

需要自己修改用户名、密码、数据库url

添加方法需要每个表单独定义方法（要改哪里一看就会）

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package com.example.helloworld.Utils;

import java.sql.*;

public class JDBCUtils {
    public static Connection getConn(){
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        Connection conn = null;
        //mysql用户名
        String userName = "root";
        //mysql密码
        String password = "password";
        //数据库URL
        String url = "jdbc:mysql://localhost:3306/<数据库名>?useSSL=false";

        try {
            conn = DriverManager.getConnection(url, userName, password);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return conn;
    }


//查询
    public static String GetData(String table,String column,String name,String col){
        Connection conn = getConn();
        String a = null;

        Statement stmt;
        try {
            stmt = conn.createStatement();
            String sql;
            sql = "SELECT * FROM "+table + " WHERE " + column + "='" + name+"'";
            ResultSet rs = stmt.executeQuery(sql);
            while (rs.next()) {
                a=rs.getString(col);
            }
            rs.close();
            stmt.close();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return a;
    }


    public static String pGetData(String table, String column, String name, String col) {
        Connection conn = getConn();
        String a = null;
        PreparedStatement ps = null;
        try {
            //创建prepareStatement对象
            String sql = "SELECT * FROM "+table+" WHERE "+column+" = ?";
            ps = conn.prepareStatement(sql);
            ps.setString(1, name);
            ps.execute();//执行
            System.out.println(ps.execute());//执行表输出返回的结果，结果为false，因为没有返回的结果集
            //处理结果集
            ResultSet rs=ps.executeQuery();
            while(rs.next()){
                a=rs.getString(col);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            //关闭资源
            try {
                if (ps != null) ps.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            try {
                if (conn != null) conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        return a;
    }


//更新
    public static void UpdateData(String table, String column, String name, String col , String newdata) {
        Connection conn = getConn();
        Statement stmt;
        try {
            stmt = conn.createStatement();
            String sql;
            sql = "UPDATE "+ table + " SET " + col + " = '"+newdata + "' WHERE " + column + " = '"+name+"'";
            stmt.executeUpdate(sql);
            stmt.close();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public static void pUpdateData(String table, String column, String name, String col , String newdata) {
        Connection conn = getConn();
        PreparedStatement ps = null;
        try {
            //创建prepareStatement对象
            String sql = "UPDATE "+table+" SET "+col+" = ? WHERE "+column+" = ?";
            ps = conn.prepareStatement(sql);
            //执行sql语句
            //ps.setString(1, table);
            //ps.setString(2, col);
            ps.setString(1, newdata);
            //ps.setString(4, column);
            ps.setString(2, name);
            //java.util.Date utilDate = new java.util.Date();//进行类型转换，由util类型的date转化为sql类型的
            ps.execute();//执行
            System.out.println(ps.execute());//执行表输出返回的结果，结果为false，因为没有返回的结果集
            //处理结果集
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            //关闭资源
            try {
                if (ps != null) ps.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            try {
                if (conn != null) conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

//删除
    public static void DeleteData(String table,String col,String name){
        Connection conn = getConn();
        Statement stmt;
        try {
            stmt = conn.createStatement();
            String sql;
            sql = "DELETE FROM "+table + " WHERE " + col + "='" + name+"'";
            stmt.executeUpdate(sql);
            stmt.close();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }


    public static void pDeleteData(String table,String col,String name){
        Connection conn = getConn();
        PreparedStatement ps = null;
        try {
            //创建prepareStatement对象
            String sql = "DELETE FROM "+table + " WHERE " + col + "= ?";
            ps = conn.prepareStatement(sql);
            //执行sql语句
            ps.setString(1, name);
            //java.util.Date utilDate = new java.util.Date();//进行类型转换，由util类型的date转化为sql类型的
            ps.execute();//执行
            System.out.println(ps.execute());//执行表输出返回的结果，结果为false，因为没有返回的结果集
            //处理结果集
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            //关闭资源
            try {
                if (ps != null) ps.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            try {
                if (conn != null) conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

//添加
    public static void AddDatastu(String name1,String password1,String qqaccount1){
        Connection conn = getConn();
        Statement stmt;
        try {
            stmt = conn.createStatement();
            String sql;
            sql = "insert into stu(stuname,password,qq) values ('"+name1+"','"+password1+"','"+qqaccount1+"');";
            stmt.executeUpdate(sql);
            stmt.close();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public static void pAddDatastu(String name1,String password1,String qqaccount1){
        Connection conn = getConn();
        PreparedStatement ps = null;
        try {
            //创建prepareStatement对象
            String sql = "insert into stu(stuname,password,qq) values (?,?,?)";
            ps = conn.prepareStatement(sql);
            //执行sql语句
            ps.setString(1, name1);
            ps.setString(2,password1);
            ps.setString(3,qqaccount1);
            //java.util.Date utilDate = new java.util.Date();//进行类型转换，由util类型的date转化为sql类型的
            //ps.execute();
            // 执行
            System.out.println(ps.execute());//执行表输出返回的结果，结果为false，因为没有返回的结果集
            //处理结果集
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            //关闭资源
            try {
                if (ps != null) ps.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            try {
                if (conn != null) conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

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