eclipse連接mysql

1.首先在mysql的官網里選擇要下的mysql版本和jar包

2.依照教程一步步安裝

3.配置tomcat

4.重點說一下期間遇到的問題：1.http 404和http 500

2.access denied at localhost：3306（using password：yes）

一開始我按照資料打算修改root 密碼，但是搞了很久，修改my.ini，用skip跳過權限檢查，好不容易改了密碼，結果mysql8.0以上的版本不再支持12345這種簡單的密碼，說不安全。於是我卸載重下，這里比較要注意的一點是，mysql一定要完全卸載干凈然后再重新配置，否則出現的問題和上次一模一樣。並且eclipse連接不上mysql的數據庫。所以下載的時候最好看詳細的教程。

代碼這塊我參考的是同學的代碼，

主要有五個塊：前端界面顯示，后端數據添加，三個java類。

1.

package bean; public class Classadd { private String classname; private String teachername; private String place; public String getClassname() { return classname; } public void setClassname(String classname) { this.classname = classname; } public String getTeachername() { return teachername; } public void setTeachername(String teachername) { this.teachername = teachername; } public String getPlace() { return place; } public void setPlace(String place) { this.place = place; } } 2.package Dao; import java.sql.*; import bean.Classadd; import JDBC.ClassaddJDBC; public class Useradddao {

public void add(Classadd clas) {
        //獲得鏈接對象
        Connection connection = ClassaddJDBC.getConnection();

        //准備sql語句
        String sql = "insert into classadd(classname,teachername,place) values(?,?,?)";
        System.out.println(sql);
        PreparedStatement preparedStatement = null;
        try {
        //創建語句傳輸對象
        preparedStatement = connection.prepareStatement(sql);
        preparedStatement = connection.prepareStatement(sql);
        preparedStatement = connection.prepareStatement(sql);
        preparedStatement.setString(1, clas.getClassname());
        preparedStatement.setString(2, clas.getTeachername());
        preparedStatement.setString(3, clas.getPlace());
        preparedStatement.executeUpdate();
        System.out.println(clas.getClassname());
        System.out.println(clas.getTeachername());
        System.out.println(clas.getPlace());
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            //關閉資源

            ClassaddJDBC.close(preparedStatement);
            ClassaddJDBC.close(connection);
        }

    }

}
3.
package JDBC;
import java.sql.*;
public class ClassaddJDBC {
public static Connection getConnection() {
try {

        Class.forName("com.mysql.jdbc.Driver");
    } catch ( ClassNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    Connection connection = null;
    String user = "root";
    String password = "Lyf123456!";
    String url = "jdbc:mysql://localhost:3306/newclassadd?serverTimezone=UTC";
    
    try {
    	
         connection = DriverManager.getConnection(url,user,password);
    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return connection;
}


public static void close(Connection connection ) {
    try {
        if (connection != null) {
            connection.close();
        }

    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}
public static void close(PreparedStatement preparedStatement ) {
    try {
        if (preparedStatement != null) {
            preparedStatement.close();
        }

    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}
public static void close(ResultSet resultSet ) {
    try {
        if (resultSet != null) {
            resultSet.close();
        }

    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

}
4.<%@page import="Dao.Useradddao"%>
<%@page import="bean.Classadd"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>

<% //接收客戶端傳遞過來的參數

String teachername = request.getParameter("teachername");
String classname = request.getParameter("classname");
String place = request.getParameter("place");

    Classadd haveclass = new Classadd();
    haveclass.setTeachername(teachername);
    haveclass.setClassname(classname);
    haveclass.setPlace(place);
    Useradddao classDao = new Useradddao();
    classDao.add(haveclass); 
 %>

5.<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>

        <tr align="center">
            <td colspan="2">
                <input type="submit" value="提交" />
                <input type="reset" value="重置" />
            </td>
        </tr>
    </table>
</form>

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