数据库操作工具（CRUD）

package connectionutil;

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

public class ConnectionUtil {
    private static String URL="jdbc:mysql://localhost:3307/scott"+"?useSSL=false&useUnicode=true"+"&characterEncoding=UTF-8&serverTimezone=UTC";
    //	private static String URL = "jdbc:mysql://localhost:3307/scott" +"?useUnicode=true&useJDBCCompliantTimezoneShift=true"+"&useLegacyDatetimeCode=false&serverTimezone=UTC";
    private static String DRIVER="com.mysql.cj.jdbc.Driver";
    private static String USER = "biubiu";
    private static String PASSWORD = "123456";
    //加载驱动
    static{
        try {
            Class.forName(DRIVER);
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    
    public static Connection getConnection(){
        try {
            return DriverManager.getConnection(URL,USER,PASSWORD);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }
    public static void close(Connection conn){
        try {
            conn.close();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}

package connectionutil;
import java.io.Serializable;
import java.util.Date;

public class Emp implements Serializable {
    private Integer empno;
    private String ename;
    private String job;
    private Integer mgr;
    private Double sal;
    private Date hiredate;
    private Double comm;
    private Integer deptno;

    public Emp() {
    }

    public Emp(Integer empno, String ename, String job, Integer mgr, Double sal, Date hiredate, Double comm, Integer deptno) {
        this.empno = empno;
        this.ename = ename;
        this.job = job;
        this.mgr = mgr;
        this.sal = sal;
        this.hiredate = hiredate;
        this.comm = comm;
        this.deptno = deptno;
    }

    public Integer getEmpno() {
        return empno;
    }

    public void setEmpno(Integer empno) {
        this.empno = empno;
    }

    public String getEname() {
        return ename;
    }

    public void setEname(String ename) {
        this.ename = ename;
    }

    public String getJob() {
        return job;
    }

    public void setJob(String job) {
        this.job = job;
    }

    public Integer getMgr() {
        return mgr;
    }

    public void setMgr(Integer mgr) {
        this.mgr = mgr;
    }

    public Double getSal() {
        return sal;
    }

    public void setSal(Double sal) {
        this.sal = sal;
    }

    public Date getHiredate() {
        return hiredate;
    }

    public void setHiredate(Date hiredate) {
        this.hiredate = hiredate;
    }

    public Double getComm() {
        return comm;
    }

    public void setComm(Double comm) {
        this.comm = comm;
    }

    public Integer getDeptno() {
        return deptno;
    }

    public void setDeptno(Integer deptno) {
        this.deptno = deptno;
    }

    @Override
    public String toString() {
        return "Emp{" +
                "empno=" + empno +
                ", ename='" + ename + ''' +
                ", job='" + job + ''' +
                ", mgr=" + mgr +
                ", sal=" + sal +
                ", hiredate=" + hiredate +
                ", comm=" + comm +
                ", deptno=" + deptno +
                '}';
    }
}

package connectionutil.demo;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.sql.*;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
public class Dbuttil {
    private static PreparedStatement pst;
    private static ResultSet rst;

    
    public static int remove(Connection conn,String sql,Object...params) throws Exception{
        pst = conn.prepareStatement(sql);
        for (int i =0;i ids)throws Exception{
        Iterator