javaweb访问数据库进行查找更新

最新推荐文章于 2025-05-07 10:01:50 发布

ECNU_Cheng

最新推荐文章于 2025-05-07 10:01:50 发布

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CC 4.0 BY-SA版权

文章标签：数据库 java web

本文链接：https://blog.youkuaiyun.com/ecnu_cheng/article/details/72514129

该博客介绍了如何在Java Web应用中连接MySQL数据库，实现通过ID查找、更新记录以及遍历所有数据的功能。提供了相关的测试代码及数据库表数据的示例。

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与mysql数据库建立连接

package cn.java.mydoc.dao.impl;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;

import javax.resource.cci.ResultSet;


public class BaseDao {
private static String driver="com.mysql.jdbc.Driver";
private static String url="jdbc:mysql://localhost:3306/test1";
private static String user="root";
private static String password="123456";

public static Connection getConnection(){
Connection conn =null;
try{
Class.forName(driver);
conn = DriverManager.getConnection(url, user, password);
if(!conn.isClosed()){
System.out.println("succeed connecting to database");
}
}catch(Exception e){
e.printStackTrace();
}
return conn;

}

public static void closeAll(Connection conn,Statement stmt,ResultSet rs){
if(rs!=null){
try{
rs.close();
}catch(Exception e){
e.printStackTrace();
}
}
if(stmt!=null){
try{
stmt.close();
}catch(Exception e){
e.printStackTrace();
}
}
if(conn!=null){
try{
conn.close();
}catch(Exception e){
e.printStackTrace();
}
}
}
}

实现按id查找、更新、和全部遍历

package cn.java.mydoc.dao.impl;

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import java.sql.Connection;

import cn.java.mydoc.bean.Profile;

public class ProfileDao extends BaseDao {
     public List<Profile> getAll(){
         Connection connection = getConnection();
         PreparedStatement pstmt = null;
         ResultSet rs =null;
         String sql="select * from profile";
         List<Profile> profileList = new ArrayList<Profile>();
         try{
             pstmt = connection.prepareStatement(sql);
             rs=pstmt.executeQuery();
             while(rs.next()){
                 Profile profile = new Profile();
                 profile.setid(rs.getInt("id"));
                 profile.setname(rs.getString("name"));
                 profile.setbirthday(rs.getString("birthday"));
                 profile.setgender(rs.getString("gender"));
                 profile.setcareer(rs.getString("career"));
                 profile.setaddress(rs.getString("address"));
                 profile.setmobile(rs.getString("mobile"));
                 profileList.add(profile);
             }
         }catch(SQLException e){
             e.printStackTrace();
         }finally{
             closeAll(connection,pstmt,null);
         }
         return profileList;
     }



public void updateProfile(Profile profile){
    Connection connection = null;
    PreparedStatement pstmt = null;
    String sql = "update profile set name=?,birthday=?,gender=?,career=?,address=?,mobile=? where id="+profile.getid();
    try{
        connection = BaseDao.getConnection();
        pstmt = connection.prepareStatement(sql);
        pstmt.setString(1, profile.getname());
        pstmt.setString(2, profile.getbirthday());
        pstmt.setString(3, profile.getgender());
        pstmt.setString(4, profile.getcareer());
        pstmt.setString(5, profile.getaddress());
        pstmt.setString(6, profile.getmobile());
        pstmt.execute();
    }catch(SQLException e){
        e.printStackTrace();
    }finally{
        closeAll(connection,pstmt,null);
    }
}


public Profile getProfile(int id){
    Connection connection =  getConnection();
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    String sql = "select * from profile where id="+id;
    Profile profile = new Profile();
    try{
        pstmt = connection.prepareStatement(sql);
        rs = pstmt.executeQuery();
        while(rs.next()){
            profile.setid(rs.getInt("id"));
            profile.setname(rs.getString("name"));
            profile.setbirthday(rs.getString("birthday"));
            profile.setgender(rs.getString("gender"));
            profile.setcareer(rs.getString("career"));
            profile.setaddress(rs.getString("address"));
            profile.setmobile(rs.getString("mobile"));
         }
    }catch(SQLException e){
        e.printStackTrace();
    }finally{
        closeAll(connection,pstmt,null);
    }
    return profile;

}

}

下图为数据库表数据这里写图片描述

测试类代码

package cn.java.mydoc.biz.impl;

import java.util.List;

import cn.java.mydoc.bean.Profile;
import cn.java.mydoc.dao.impl.ProfileDao;

public abstract class test {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        ProfileDao profiledao = new ProfileDao();
        List<Profile> list = profiledao.getAll();
        if(list.size()>0){
            System.out.println("getAll()ok" );
        }else{
            System.out.println("getAll()roung");
        }

        Profile profile = profiledao.getProfile(2);
        if(profile!=null){
            System.out.println("getProfile()ok");
        }else{
            System.out.println("getProfile()roung");
        }

        Profile profile1 = profiledao.getProfile(3);
        profile1.setbirthday("isTomo");

        profiledao.updateProfile(profile1);



    }

}

测试结果：
这里写图片描述