利用mvn juint 连接数据库进行操作（修改）

package com.jdbc02;

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

public class BaseDao {
        Connection cc = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        private static final String driver = "com.mysql.cj.jdbc.Driver";
        private final String url = "jdbc:mysql://127.0.0.1:3306/class?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=UTC";
        private final String user = "root";
        private static final String password = "emp2014ljh";
        //获取数据库连接
        public void getConnection() {
            try {
                Class.forName(driver);
                cc =     DriverManager.getConnection(url, user, password);
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        //查询方法
        public ResultSet executeQuery(String sql ,Object... obj) {
            getConnection();
            try {
                ps = cc.prepareStatement(sql);
                if(obj != null) {
                    for(int i = 0;i < obj.length;i++) {
                        ps.setObject((i+1), obj[i]);
                    }
                }
                rs = ps.executeQuery();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            
            return rs;
        }
        //跟新方法（增加删除修改）
        public int executeUpdate(String sql,Object... obj) {
            getConnection();
            int result = 0;
            try {
                ps = cc.prepareStatement(sql);
                if(obj != null) {
                    for(int i = 0;i < obj.length;i++) {
                        ps.setObject((i+1), obj[i]);
                    }
                }
                result = ps.executeUpdate();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally {
                closeAll();
            }
            
            
            
            
            return result;
        }
        //释放资源
        public void closeAll() {
            try {
                if(rs != null) {
                    rs.close();
                }
                if (ps!=null){
                    ps.close();
                }
                if (cc!=null){
                    cc.close();
                }
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        
        

}

package com.test;

import java.sql.ResultSet;
import java.sql.SQLException;

import org.junit.Test;

import com.jdbc02.BaseDao;

public class jdbc_test {
    @Test
    //查询全部学生信息
    public void test01()  {
        BaseDao bd = new BaseDao();
        Object[] obj = {};
        ResultSet rs = bd.executeQuery("SELECT * FROM STUDENT",obj);
        try {
            while(rs.next()) {
                System.out.println(rs.getObject(1).toString()+"	"+rs.getObject(2).toString()+"	"+rs.getObject(3).toString()+"	"
            +rs.getObject(4).toString()+"	"+rs.getObject(5).toString()+"	"+rs.getObject(6).toString()+"	"+rs.getObject(7).toString()
            +"	"+rs.getObject(8).toString());
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        bd.closeAll();
        
    }
    @Test
    //查询某个的全部信息
    public void test02() {
        BaseDao bd = new BaseDao();
        String sql ="SELECT * FROM STUDENT  where id = ?" ;
        Object[] obj = {2};
        ResultSet rs = bd.executeQuery(sql, obj);
        try {
            while(rs.next()) {
                System.out.println(rs.getObject(1).toString()+"	"+rs.getObject(2).toString()+"	"+rs.getObject(3).toString()+"	"
                        +rs.getObject(4).toString()+"	"+rs.getObject(5).toString()+"	"+rs.getObject(6).toString()+"	"+rs.getObject(7).toString()
                        +"	"+rs.getObject(8).toString());
            }
            bd.closeAll();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    @Test
    public void test03() {
        BaseDao bd = new BaseDao();
        String sql ="SELECT id,username,phone,address FROM student where usercode=?;" ;
        Object[] obj = {"guapi"};
        ResultSet rs = bd.executeQuery(sql, obj);
        try {
            while(rs.next()) {
                System.out.println(rs.getObject("id")+"	"+rs.getObject(2)+"	"+rs.getObject(3));
            }
            bd.closeAll();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        bd.closeAll();
    }
    @Test
    //添加信息
    public void test04() {
        BaseDao bd = new BaseDao();
        String sql = "INSERT INTO student VALUES(?,?,?,?,?,?,?,?);";
        Object[] obj = {4,"guapi","瓜皮","123456",1,"15350593845","1997-03-30","北京市"};
        int result = bd.executeUpdate(sql, obj);
        if(result >0) {
            System.out.println("添加成功");
        }else {
            System.out.println("添加失败");
        }
    }
    @Test
    //删除信息
    public void test05() {
        BaseDao bd = new BaseDao();
        String sql = "DELETE FROM student where id=?";
        Object[] obj = {5};
        int a = bd.executeUpdate(sql, obj);
        if(a >0) {
            System.out.println("删除成功");
        }else {
            System.out.println("删除失败");
        }
    }
    //跟新信息
    @Test
    public void Test06() {
        BaseDao bd = new BaseDao();
        String sql = "update student SET `password`='654321' WHERE id = ?;";
        Object[] obj = {4};
        int b = bd.executeUpdate(sql, obj);
        if(b>0) {
            System.out.println("修改成功");
        }else {
            System.out.println("修改失败");
        }
    }
}

 测试类添加修改类