12.5

有一说一，今天几乎没有学习。今天有事去龙山办活动在那边待了一天，回来也差不多到现在了。所以写一写dao层的代码吧！

员工培训系统。。dao层

链接数据库代码

package dao;
import java.sql.*;
public class DBUtil {
    //eshop为数据库名称，db_user为数据库用户名db_password为数据库密码
    public static String db_url = "jdbc:mysql://localhost:3306/staffmanage?useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT";
    public static String db_user = "root";
    public static String db_password = "root1";

    public static Connection getConn() {
        Connection conn = null;
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            conn = DriverManager.getConnection(db_url, db_user, db_password);
            System.out.println("连接成功");
        } catch (Exception e) {
            System.out.println("连接失败");
            e.printStackTrace();
        }
        return conn;
    }
    
    public static void close(Statement state, Connection conn) {
        if(state!=null) {
            try {
                state.close();
            } catch (SQLException e) {
                e.printStackTrace();    
            }
        }    
        if(conn!=null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
    
    public static void close(ResultSet rs, Statement state, Connection conn) {
        if(rs!=null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if(state!=null) {
            try {
                state.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if(conn!=null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

package dao;

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


import entity.Staff;

public class StaffDaoImpl implements StaffDao{
    Connection conn=(Connection)DBUtil.getConn();
    
    public String teachershowpass(String iD) {
        // TODO 自动生成的方法存根
        String password=null;
        try {
            String sql="select * from teacher where teaID=?";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setString(1,iD);
            ResultSet rs = pstmt.executeQuery();
            while(rs.next()) {
                Staff staff=new Staff();
                
                staff.setTeapassword(rs.getString("teapassword"));
                password=staff.getTeapassword();
                
            }
            rs.close();
            pstmt.close();
            conn.close();
        }catch(SQLException e) {
            e.printStackTrace();
        }
        return password;
    }

    public String stushowpass(String iD) {
        // TODO 自动生成的方法存根
        String password=null;
        try {
            String sql="select * from student where stuID=?";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setString(1,iD);
            ResultSet rs = pstmt.executeQuery();
            while(rs.next()) {
                Staff staff=new Staff();                
                staff.setStupassword(rs.getString("stupassword"));
                password=staff.getStupassword();                
            }
            rs.close();
            pstmt.close();
            conn.close();
        }catch(SQLException e) {
            e.printStackTrace();
        }
        return password;
    }

    public List<Staff> stushow(String iD) {
        // TODO 自动生成的方法存根
        List<Staff> list = new ArrayList<Staff>();
        try {
            System.out.println(1);
            String sql="select * from student where stuID=?";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setString(1,iD);
            ResultSet rs = pstmt.executeQuery();
            System.out.println(2);
            while(rs.next()) {
                Staff school=new Staff();
                    school.setStuID(rs.getString("stuID"));
                    
                    school.setStuname(rs.getString("stuname"));
                    school.setStusex(rs.getString("stusex"));
                    school.setStuclass(rs.getString("stuclass"));    
                    school.setStutitle(rs.getString("stutitle"));
                list.add(school);
            }
            rs.close();
            pstmt.close();
            conn.close();

        }catch(SQLException e) {
            e.printStackTrace();
        }
        
        return list;
    }

    public boolean stuupdate(String stuID, String stuname, String stusex, String stuclass, String stutitle) {
        // TODO 自动生成的方法存根
        boolean flag=false;
        try {
            String sql="update student set stuname=?,stusex=?,stuclass=?,stutitle=?where stuID=?";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setString(5, stuID);
            pstmt.setString(1,stuname);
            System.out.println(stuname+'2');
            pstmt.setString(2,stusex);
            pstmt.setString(3,stuclass);
            pstmt.setString(4,stutitle);
            int i = pstmt.executeUpdate();
            pstmt.close();
            conn.close();
            if(i>0) {flag = true;System.out.println("修改成功！！！");}
        }catch(SQLException e) {      
            e.printStackTrace();
        }
        return flag;
    }

    public List<Staff> stushowgrade(String iD) {
        // TODO 自动生成的方法存根
        List<Staff> list = new ArrayList<Staff>();
        try {
            System.out.println(1);
            String sql="select * from grade where stuID=?";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setString(1,iD);
            ResultSet rs = pstmt.executeQuery();
            System.out.println(2);
            while(rs.next()) {
                Staff school=new Staff();
                    school.setStuID(rs.getString("stuID"));
                    school.setStuname(rs.getString("stuname"));
                    school.setCourse(rs.getString("course"));
                    school.setGrade(rs.getString("grade"));    
                list.add(school);
            }
            rs.close();
            pstmt.close();
            conn.close();
        }catch(SQLException e) {
            e.printStackTrace();
        }
        return list;
    }

    public List<Staff> teashow(String teaID) {
        // TODO 自动生成的方法存根
        List<Staff> list = new ArrayList<Staff>();
        try {
            System.out.println(1);
            String sql="select * from teacher where teaID=?";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setString(1,teaID);
            ResultSet rs = pstmt.executeQuery();
            System.out.println(2);
            while(rs.next()) {
                Staff school=new Staff();
                    school.setTeaID(rs.getString("teaID"));
                    
                    school.setTeaname(rs.getString("teaname"));
                    school.setTeasex(rs.getString("teasex"));
                    school.setTeaclass(rs.getString("teaclass"));    
                    school.setTeatitle(rs.getString("teatitle"));
                list.add(school);
            }
            rs.close();
            pstmt.close();
            conn.close();

        }catch(SQLException e) {
            e.printStackTrace();
        }
        
        return list;
    }

    public boolean teaupdate(String teaID, String teaname, String teasex, String teaclass, String teatitle) {
        // TODO 自动生成的方法存根
        boolean flag=false;
        try {
            String sql="update student set teaname=?,teasex=?,teaclass=?,teatitle=?where teaID=?";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setString(5, teaID);
            pstmt.setString(1,teaname);
            System.out.println(teaname+'2');
            pstmt.setString(2,teasex);
            pstmt.setString(3,teaclass);
            pstmt.setString(4,teatitle);
            int i = pstmt.executeUpdate();
            pstmt.close();
            conn.close();
            if(i>0) {flag = true;System.out.println("修改成功！！！");}
        }catch(SQLException e) {      
            e.printStackTrace();
        }
        return flag;
    }

    public boolean gradeadd(String stuID, String stuname, String course, String grade,String teaID) {
        // TODO 自动生成的方法存根
        boolean flag=false;
        PreparedStatement ps=null;
        try {
            System.out.println("jinru");
            ps=conn.prepareStatement("insert into grade(stuID,stuname,course,grade,teaID)"+"values(?,?,?,?,?)");            
            ps.setString(1,stuID);
            ps.setString(2,stuname);
            ps.setString(3,course);
            ps.setString(4,grade);
            ps.setString(5, teaID);
            System.out.println("jinru123");
            int i=ps.executeUpdate();
            ps.close();
            conn.close();
            
            if(i>0) {
                flag = true;System.out.println("添加成功");
            }

        }catch(SQLException e) {
            e.printStackTrace();
        }
        return flag;    
    }

    public List<Staff> gradeshow(String teaID) {
        // TODO 自动生成的方法存根
        List<Staff> list = new ArrayList<Staff>();
        try {
            System.out.println(1);
            String sql="select * from grade where teaID=?";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setString(1,teaID);
            ResultSet rs = pstmt.executeQuery();
            System.out.println(2);
            while(rs.next()) {
                Staff school=new Staff();
                    school.setStuID(rs.getString("stuID"));
                    school.setStuname(rs.getString("stuname"));
                    school.setCourse(rs.getString("course"));
                    school.setGrade(rs.getString("grade"));    
                    school.setTeaID(rs.getString("teaID"));
                list.add(school);
            }
            rs.close();
            pstmt.close();
            conn.close();
        }catch(SQLException e) {
            e.printStackTrace();
        }
        return list;
    }

    public boolean updategrade(String stuID, String grade) {
        // TODO 自动生成的方法存根
        boolean flag=false;
        try {
            String sql="update grade set grade=?where stuID=?";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            
            pstmt.setString(1,grade);
            
            pstmt.setString(2,stuID);
            
            int i = pstmt.executeUpdate();
            pstmt.close();
            conn.close();
            if(i>0) {flag = true;System.out.println("修改成功！！！");}
        }catch(SQLException e) {      
            e.printStackTrace();
        }
        return flag;
    }

    public List<Staff> showpass() {
        // TODO 自动生成的方法存根
        List<Staff> list = new ArrayList<Staff>();
        try {
            System.out.println(1);
            String sql="select * from grade WHERE grade >='60'";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            
            ResultSet rs = pstmt.executeQuery();
            System.out.println(2);
            while(rs.next()) {
                Staff school=new Staff();
                    school.setStuID(rs.getString("stuID"));
                    school.setStuname(rs.getString("stuname"));
                    school.setCourse(rs.getString("course"));
                    school.setGrade(rs.getString("grade"));    
                    school.setTeaID(rs.getString("teaID"));
                list.add(school);
            }
            rs.close();
            pstmt.close();
            conn.close();
        }catch(SQLException e) {
            e.printStackTrace();
        }
        return list;
    }

    public List<Staff> showexcellent() {
        // TODO 自动生成的方法存根
        List<Staff> list = new ArrayList<Staff>();
        try {
            System.out.println(1);
            String sql="select * from grade WHERE grade >='90'";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            
            ResultSet rs = pstmt.executeQuery();
            System.out.println(2);
            while(rs.next()) {
                Staff school=new Staff();
                    school.setStuID(rs.getString("stuID"));
                    school.setStuname(rs.getString("stuname"));
                    school.setCourse(rs.getString("course"));
                    school.setGrade(rs.getString("grade"));    
                    school.setTeaID(rs.getString("teaID"));
                list.add(school);
            }
            rs.close();
            pstmt.close();
            conn.close();
        }catch(SQLException e) {
            e.printStackTrace();
        }
        return list;
    }

    public List<Staff> allstushow() {
        // TODO 自动生成的方法存根
        List<Staff> list = new ArrayList<Staff>();
        try {
            System.out.println(1);
            String sql="select * from student";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            
            ResultSet rs = pstmt.executeQuery();
            System.out.println(2);
            while(rs.next()) {
                Staff school=new Staff();
                    school.setStuID(rs.getString("stuID"));
                    school.setStuname(rs.getString("stuname"));
                    school.setStusex(rs.getString("stusex"));
                    school.setStuclass(rs.getString("stuclass"));    
                    school.setStutitle(rs.getString("stutitle"));
                list.add(school);
            }
            rs.close();
            pstmt.close();
            conn.close();
        }catch(SQLException e) {
            e.printStackTrace();
        }
        return list;
    }

    public List<Staff> allteashow() {
        // TODO 自动生成的方法存根
        List<Staff> list = new ArrayList<Staff>();
        try {
            System.out.println(1);
            String sql="select * from teacher";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            
            ResultSet rs = pstmt.executeQuery();
            System.out.println(2);
            while(rs.next()) {
                Staff school=new Staff();
                    school.setTeaID(rs.getString("teaID"));
                    school.setTeaname(rs.getString("teaname"));
                    school.setTeasex(rs.getString("teasex"));
                    school.setTeaclass(rs.getString("teaclass"));    
                    school.setTeatitle(rs.getString("teatitle"));
                list.add(school);
            }
            rs.close();
            pstmt.close();
            conn.close();
        }catch(SQLException e) {
            e.printStackTrace();
        }
        return list;
    }

    public boolean addtea(String iD, String name, String sex, String class1, String title) {
        // TODO 自动生成的方法存根
        boolean flag=false;
        PreparedStatement ps=null;
        try {
            System.out.println("jinru");
            ps=conn.prepareStatement("insert into teacher(teaID,teaname,teasex,teaclass,teatitle)"+"values(?,?,?,?,?)");            
            ps.setString(1,iD);
            ps.setString(2,name);
            ps.setString(3,sex);
            ps.setString(4,class1);
            ps.setString(5, title);
            System.out.println("jinru123");
            int i=ps.executeUpdate();
            ps.close();
            conn.close();
            
            if(i>0) {
                flag = true;System.out.println("添加成功");
            }

        }catch(SQLException e) {
            e.printStackTrace();
        }
        return flag;    
    }

    public boolean addstu(String iD, String name, String sex, String class1, String title) {
        // TODO 自动生成的方法存根
        boolean flag=false;
        PreparedStatement ps=null;
        try {
            System.out.println("jinru");
            ps=conn.prepareStatement("insert into student(stuID,stuname,stusex,stuclass,stutitle)"+"values(?,?,?,?,?)");            
            ps.setString(1,iD);
            ps.setString(2,name);
            ps.setString(3,sex);
            ps.setString(4,class1);
            ps.setString(5, title);
            System.out.println("jinru123");
            int i=ps.executeUpdate();
            ps.close();
            conn.close();
            
            if(i>0) {
                flag = true;System.out.println("添加成功");
            }

        }catch(SQLException e) {
            e.printStackTrace();
        }
        return flag; 
    }

    public List<Staff> shownopass() {
        // TODO 自动生成的方法存根
        List<Staff> list = new ArrayList<Staff>();
        try {
            System.out.println(1);
            String sql="select * from grade WHERE grade <'60'";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            
            ResultSet rs = pstmt.executeQuery();
            System.out.println(2);
            while(rs.next()) {
                Staff school=new Staff();
                    school.setStuID(rs.getString("stuID"));
                    school.setStuname(rs.getString("stuname"));
                    school.setCourse(rs.getString("course"));
                    school.setGrade(rs.getString("grade"));    
                    school.setTeaID(rs.getString("teaID"));
                list.add(school);
            }
            rs.close();
            pstmt.close();
            conn.close();
        }catch(SQLException e) {
            e.printStackTrace();
        }
        return list;
    }

    public boolean deletetea(String iD) {
        // TODO 自动生成的方法存根
        boolean flag=false;
        PreparedStatement ps=null;
        try {
            System.out.println("jinru");
            ps=conn.prepareStatement("delete from teacher where teaID=?");            
            ps.setString(1,iD);

            System.out.println("jinru123");
            int i=ps.executeUpdate();
            ps.close();
            conn.close();
            
            if(i>0) {
                flag = true;System.out.println("删除成功");
            }

        }catch(SQLException e) {
            e.printStackTrace();
        }
        return flag; 
    }

    public boolean deletestu(String iD) {
        // TODO 自动生成的方法存根
        boolean flag=false;
        PreparedStatement ps=null;
        try {
            System.out.println("jinru");
            ps=conn.prepareStatement("delete from student where stuID=?");            
            ps.setString(1,iD);

            System.out.println("jinru123");
            int i=ps.executeUpdate();
            ps.close();
            conn.close();
            
            if(i>0) {
                flag = true;System.out.println("删除成功");
            }

        }catch(SQLException e) {
            e.printStackTrace();
        }
        return flag;
    }

    public boolean updatetea(String iD1, String name, String sex, String class1, String title) {
        // TODO 自动生成的方法存根
        boolean flag=false;
        try {
            String sql="update teacher set teaname=?,teasex=?,teaclass=?,teatitle=?where teaID=?";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setString(5, iD1);
            pstmt.setString(1,name);
            pstmt.setString(2,sex);
            pstmt.setString(3,class1);
            pstmt.setString(4,title);
            int i = pstmt.executeUpdate();
            
            pstmt.close();
            conn.close();
            if(i>0) {flag = true;System.out.println("修改成功！！！");}
        }catch(SQLException e) {
       
            e.printStackTrace();
        }

        return flag;
    }

    public boolean updatestu(String iD1, String name, String sex, String class1, String title) {
        // TODO 自动生成的方法存根
        boolean flag=false;
        try {
            String sql="update student set teaname=?,teasex=?,teaclass=?,teatitle=?where teaID=?";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setString(5, iD1);
            pstmt.setString(1,name);
            pstmt.setString(2,sex);
            pstmt.setString(3,class1);
            pstmt.setString(4,title);
            int i = pstmt.executeUpdate();
            
            pstmt.close();
            conn.close();
            if(i>0) {flag = true;System.out.println("修改成功！！！");}
        }catch(SQLException e) {
       
            e.printStackTrace();
        }

        return flag;
    }
    
    
    
    
    
    

}

数据层代码

package entity;

public class Staff {
    private String stuID;
    private String stupassword;
    private String stuname;
    private String stusex;
    private String stuclass;
    private String stutitle;
    private String course;
    private String grade;
    
    public String getCourse() {
        return course;
    }
    public void setCourse(String course) {
        this.course = course;
    }
    public String getGrade() {
        return grade;
    }
    public void setGrade(String grade) {
        this.grade = grade;
    }
    
    
    private String teaID;
    private String teapassword;
    private String teaname;
    private String teasex;
    private String teaclass;
    private String teatitle;
    
    public String getTeaID() {
        return teaID;
    }
    public void setTeaID(String teaID) {
        this.teaID = teaID;
    }
    public String getTeapassword() {
        return teapassword;
    }
    public void setTeapassword(String teapassword) {
        this.teapassword = teapassword;
    }
    public String getTeaname() {
        return teaname;
    }
    public void setTeaname(String teaname) {
        this.teaname = teaname;
    }
    public String getTeasex() {
        return teasex;
    }
    public void setTeasex(String teasex) {
        this.teasex = teasex;
    }
    public String getTeaclass() {
        return teaclass;
    }
    public void setTeaclass(String teaclass) {
        this.teaclass = teaclass;
    }
    public String getTeatitle() {
        return teatitle;
    }
    public void setTeatitle(String teatitle) {
        this.teatitle = teatitle;
    }
    public String getStuclass() {
        return stuclass;
    }
    public void setStuclass(String stuclass) {
        this.stuclass = stuclass;
    }
    public String getStutitle() {
        return stutitle;
    }
    public void setStutitle(String stutitle) {
        this.stutitle = stutitle;
    }
    public String getStuID() {
        return stuID;
    }
    public void setStuID(String stuID) {
        this.stuID = stuID;
    }
    public String getStupassword() {
        return stupassword;
    }
    public void setStupassword(String stupassword) {
        this.stupassword = stupassword;
    }
    public String getStuname() {
        return stuname;
    }
    public void setStuname(String stuname) {
        this.stuname = stuname;
    }
    public String getStusex() {
        return stusex;
    }
    public void setStusex(String stusex) {
        this.stusex = stusex;
    }
    
    
    
    
}