Day0205____数据库

环境配置

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提取码: ksh4 别升级

数据库使用一

package com_01_testfan_02_basic;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class Day02_03_数据库取数据01 {
    
    public static void main(String[] args) {
        //找一个工具去连接数据库
        Connection conn = null;
        Statement statement = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            //连接数据库
            conn = DriverManager.getConnection
            ("jdbc:mysql://118.24.13.38:3308/test?characterEncoding=utf8&useSSL=false", "zhangsan", "123123");
            
            //准备sql
            String  sql= "select * from t_user_test";
            
            //创建执行sql对象
            statement = conn.createStatement();
            //执行sql, 获取返回结果集合
            ResultSet  set=statement.executeQuery(sql);
            while (set.next()) {
                System.out.println(set.getString("uid")+" "+set.getString("loginname")+" "+set.getString("loginpass"));
            }
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            //数据库关闭
            try {
                conn.close();
                statement.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

}

数据库操作二

package com_01_testfan_02_basic;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

public class Day02_04_数据库取数据02 {
    
    public static void main(String[] args) {
        List<DbUser> list = getAllDbUserTest();
        System.out.println(list.size());
        for (DbUser dbUser : list) {
            System.out.println(dbUser);
        }
    }
    
    public static List<DbUser> getAllDbUserTest(){
        Connection conn = null;
        Statement statement = null;
        List<DbUser> list =null;
        try {
            //找一个工具去连接数据库
            Class.forName("com.mysql.jdbc.Driver");
            //连接数据库
            conn = DriverManager.getConnection
            ("jdbc:mysql://118.24.13.38:3308/test?characterEncoding=utf8&useSSL=false", "zhangsan", "123123");
            
            //准备sql
            String  sql= "select * from t_user_test";
            
            //创建执行sql对象
            statement = conn.createStatement();
            //执行sql, 获取返回结果集合
            ResultSet  set=statement.executeQuery(sql);
            list = new ArrayList<DbUser>();
            while (set.next()) {
                DbUser user = new DbUser();
                user.setUid(set.getString("uid"));
                user.setLoginname(set.getString("loginname"));
                user.setLoginpass(set.getString("loginpass"));
                list.add(user);
                //System.out.println(set.getString("uid")+" "+set.getString("loginname")+" "+set.getString("loginpass"));
            }
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            //数据库关闭
            try {
                conn.close();
                statement.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        return list;
    }

}

package com_01_testfan_02_basic;

//数据库模拟对象
public class DbUser {
    private String uid;
    private String loginname;
    private String loginpass;
    public String getUid() {
        return uid;
    }
    public void setUid(String uid) {
        this.uid = uid;
    }
    public String getLoginname() {
        return loginname;
    }
    public void setLoginname(String loginname) {
        this.loginname = loginname;
    }
    public String getLoginpass() {
        return loginpass;
    }
    public void setLoginpass(String loginpass) {
        this.loginpass = loginpass;
    }
    @Override
    public String toString() {
        return "DbUser [uid=" + uid + ", loginname=" + loginname + ", loginpass=" + loginpass + "]";
    }

}