JavaEE-实验三 Java数据库高级编程

该博客仅专为我的小伙伴提供参考而附加，没空加上代码具体解析，望各位谅解

1、在MySQL中运行以下脚本

CREATE DATABASE mydatabase;

 USE mydatabase;

 CREATE TABLE customers (

    customerID varchar(8) primary key,

    name varchar(40) default NULL,

    phone varchar(16) default NULL

);

INSERT INTO customers VALUES ('ADDIFK01','Frank Addinsell',

'(718) 555-3911');

扫描二维码关注公众号，回复： 7348496 查看本文章

INSERT INTO customers VALUES ('ALBIBB01','Bob Albinoni',

'(213) 555-7566');

 使用 JDBC编写程序读出数据库表中数据并在Console下如下输出内容 

2、调试上面实验指导部分“四、数据库分层设计”部分代码

   依据上课时教学内容补充SQLHelper类内容，为其增加

1） 执行带参数的SQL语句方法，含执行Select及CUID两个函数；

public static ResultSet executeQuery(String sql,Object[] params) {
        try {
            rs= getPreparedStatement(sql,params).executeQuery();
            return rs;
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
} 

2） 为其增加返回唯一值得函数（如计算最大值、记录数等）；

    public static Object executeQueryScala(String sql) {
        Object o=null;
        try {
             rs=executeQuery(sql, null);

            if(rs.next()) {
                o=rs.getDate(1);
            }
            if(o!=null)
                return o;
            else
                return null;
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }finally {
            DBUtil.closeAll(rs, pst, DBUtil.connection);
        }
    } 

 3） 增加返回集合的函数

    public static  List<Object[]> executeQueryList(String sql){
        Object[] o=new Object[2];
        List<Object[]> obs=new ArrayList<Object[]>();
        PreparedStatement pst =null;
        ResultSet rs =null;
        try {
            rs = DBUtil.executeQuery(sql, null);
            while(rs.next()) {       /*未知列数 因此提取不出所有*/
                o[0]=(rs.getObject(0));
                o[1]=(rs.getObject(0));
                obs.add(o);
            }
            return obs;
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }finally {
            DBUtil.closeAll(rs, pst, DBUtil.connection);
        }
    }

3、运用上面数据库设计思想，继续完成上次实验。以JDBC技术创建一个通讯录应用程序，要求通讯录中必须含有编号、姓名，性别、电话、地址、Email等等。实现该类并包含添加、删除、修改、按姓名查等几个方法。编写主程序测试。 

该程序体量较小 没增加server层 （用于连接dao层与view层）

第一步：编写一个Person联系人类

package entity;

public class Person {
    private int    pid;  //编号
    private String name; // 姓名 
    private String sex; // 性别 
    private String tel; // 电话 
    private String address; // 地址 
    private String email; //email 
    
    public Person(int pid, String name, String sex, String tel, String address, String email) {
        this.pid = pid;
        this.name = name;
        this.sex = sex;
        this.tel = tel;
        this.address = address;
        this.email = email;
    }

    public int getPid() {
        return pid;
    }
    public void setPid(int pid) {
        this.pid = pid;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public String getTel() {
        return tel;
    }
    public void setTel(String tel) {
        this.tel = tel;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    @Override
    public String toString() {
        return "Person [pid=" + pid + ", name=" + name + ", sex=" + sex + ", tel=" + tel + ", address=" + address
                + ", email=" + email + "]";
    }
    

}

 第二步：编写一个PersonDao封装对联系人类的有关操作

package dao;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import entity.Person;
import util.DBUtil;
public class PersonDao {
    //增加人
    public void addPerson(Person p){ 
        String sql="insert into customers values(?,?,?,?,?,?);";
        Object params[]= {p.getPid(),p.getName(),p.getSex(),p.getTel(),p.getAddress(),p.getEmail()};
        DBUtil.executeUpdate(sql, params);
    } 
    // 通过人的编号删除 联系人
    public void deletePersonByID(int pid){ 
        String sql="delete from person where pid=?";
        Object params[]= {pid};
        DBUtil.executeUpdate(sql,params);
    }
    //通过人的姓名查找联系人，返回一个集合
    public List<Person> queryPersonByName(String name){ 
        Person p=null;
        List<Person> ps=new ArrayList<Person>();
        PreparedStatement pst =null;
        ResultSet rs =null;
        try {
            String sql="select * from person where name=?";
            Object params[]= {name};
            rs = DBUtil.executeQuery(sql, params);
            while(rs.next()) {
                int id=rs.getInt("customerID");
                String sex=rs.getString("sex");
                String tel=rs.getString("tel");
                String address=rs.getString("address");
                String email=rs.getString("email");
                p=new Person(id, name, sex,tel,address,email);
                ps.add(p);
            }
            return ps;
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }finally {
            DBUtil.closeAll(rs, pst, DBUtil.connection);
        }
    }
    //        查询所有人
    public List<Person> quaryall(){
        Person p=null;
        List<Person> ps=new ArrayList<Person>();
        PreparedStatement pst =null;
        ResultSet rs =null;
        try {
            String sql="select * from person";
            Object params[]= {};
            rs = DBUtil.executeQuery(sql, params);
            while(rs.next()) {
                int id=rs.getInt("pid");
                String name=rs.getString("name");
                String sex=rs.getString("sex");
                String tel=rs.getString("tel");
                String address=rs.getString("address");
                String email=rs.getString("email");
                p=new Person(id, name, sex,tel,address,email);
                ps.add(p);
            }
            return ps;
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }finally {
            DBUtil.closeAll(rs, pst, DBUtil.connection);
        }
    }
    public List<Person> quarybyitems(String strsql) {
        Person p=null;
        List<Person> ps=new ArrayList<Person>();
        PreparedStatement pst =null;
        ResultSet rs =null;
        try {
            String sql="select * from person where 1=1 "+strsql;
            Object params[]= {};
            rs = DBUtil.executeQuery(sql, params);
            while(rs.next()) {
                int id=rs.getInt("pid");
                String name=rs.getString("name");
                String sex=rs.getString("sex");
                String tel=rs.getString("tel");
                String address=rs.getString("address");
                String email=rs.getString("email");
                p=new Person(id, name, sex,tel,address,email);
                ps.add(p);
            }
            return ps;
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }finally {
            DBUtil.closeAll(rs, pst, DBUtil.connection);
        }
        
    }
    public boolean update(String strsql) {
        String sql="insert person values"+strsql;
        Object[] params= {};
        return DBUtil.executeUpdate(sql, params);
    }
}

第三步：编写一个测试Swing类,有界面使用JTable显示，参考书本上关于JTable控件的使用

演示截图

package view;

import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;

import dao.PersonDao;
import entity.Person;

public class TestFrm extends JFrame{
    private static final long serialVersionUID = 1L;
    PersonDao pd=new PersonDao();
    JPanel jp1=new JPanel();
    Object[] Names1 = {"编号","姓名","性别","电话","地址","email"};
    JTable table1;
    TestFrm(){
        JLabel label1=new JLabel("编号");
        JLabel label2=new JLabel("姓名");
        JLabel label3=new JLabel("性别");
        JLabel label4=new JLabel("电话");
        JLabel label5=new JLabel("地址");
        JLabel label6=new JLabel("email");
        JTextField jt1=new JTextField();
        JTextField jt2=new JTextField();
        JTextField jt3=new JTextField();
        JTextField jt4=new JTextField();
        JTextField jt5=new JTextField();
        JTextField jt6=new JTextField();
        JButton jb1=new JButton("查询");
        JButton jb2=new JButton("增加");
        JButton jb3=new JButton("删除");
        JButton jb4=new JButton("显示所有");
        
        jp1.setLayout(new GridLayout(4, 4));
        jp1.add(label1);
        jp1.add(jt1);
        jp1.add(label2);
        jp1.add(jt2);
        jp1.add(label3);
        jp1.add(jt3);
        jp1.add(label4);
        jp1.add(jt4);
        jp1.add(label5);
        jp1.add(jt5);
        jp1.add(label6);
        jp1.add(jt6);
        jp1.add(jb1);
        jp1.add(jb2);
        jp1.add(jb3);
        jp1.add(jb4);
        jb1.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                String strsql="";
                if(!jt1.getText().isEmpty())
                    strsql+=" and pid="+jt1.getText();
                if(!jt2.getText().isEmpty())
                    strsql+=" and name='"+jt2.getText()+"'";
                if(!jt3.getText().isEmpty())
                    strsql+=" and sex='"+jt3.getText()+"'";
                if(!jt4.getText().isEmpty())
                    strsql+=" and tel='"+jt4.getText()+"'";
                if(!jt5.getText().isEmpty())
                    strsql+=" and address='"+jt5.getText()+"'";
                if(!jt6.getText().isEmpty())
                    strsql+=" and email='"+jt6.getText()+"'";
                List<Person> list = pd.quarybyitems(strsql);
                
                reset(list);
            }
        });
        jb2.addActionListener(new ActionListener() {
            
            @Override
            public void actionPerformed(ActionEvent e) {
                if(jt1.getText().isEmpty()||jt2.getText().isEmpty()||jt3.getText().isEmpty()||jt4.getText().isEmpty()||jt5.getText().isEmpty()||jt6.getText().isEmpty())
                    JOptionPane.showMessageDialog(null, "请输入完整！！");
                else {
                    String strsql="("+jt1.getText()+",\""+jt2.getText()+"\",\""+jt3.getText()+"\",\""+jt4.getText()+"\",\""+jt5.getText()+"\",\""+jt6.getText()+"\")";
                    if(pd.update(strsql)) {
                        JOptionPane.showMessageDialog(null, "插入成功");
                         List<Person> list = pd.quaryall();
                         reset(list);
                    }else {
                        JOptionPane.showMessageDialog(null, "插入失败");
                    }
                }
            }
        });
        jb3.addActionListener(new ActionListener() {
            
            @Override
            public void actionPerformed(ActionEvent e) {
                int pid= (int)table1.getModel().getValueAt(table1.getSelectedRow(), 0);
                pd.deletePersonByID(pid);
                List<Person> list = pd.quaryall();
                reset(list);
            }
        });
        jb4.addActionListener(new ActionListener() {
            
            @Override
            public void actionPerformed(ActionEvent e) {
                List<Person> list = pd.quaryall();
                reset(list);
            }
        });
        List<Person> list = pd.quaryall();
        reset(list);
        
        setTitle("我的通讯录");
        setBounds(600,400,600,350);
        setVisible(true);
        setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    }
    private void reset(List<Person> list){
        List<Object[]> b=new ArrayList<Object[]>();
        for(Person p:list) {
            Object[] o= {p.getPid(),p.getName(),p.getSex(),p.getTel(),p.getAddress(),p.getEmail()};
            b.add(o);
        }
        Object[][] a = (Object[][])b.toArray(new Object[b.size()][]);
        table1=new JTable(a,Names1);
        getContentPane().removeAll();
        add(jp1,BorderLayout.NORTH);
        add(new JScrollPane(table1),BorderLayout.CENTER);
        validate();
    }
    public static void main(String[] args) {
        new TestFrm();
    }
}

DBUtil包代码

 此句话作用 用于设置写入数据库与读取数据库数据编码

若遇到mysql中文编码问题 赶紧戳这里解决mysql编码常见问题分享

package util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

//通用的数据库操作方法
public class DBUtil {
    //sql数据库连接字符串
    private static final String URL="jdbc:mysql://127.0.0.1:3306/mydatabase?useUnicode=true&characterEncoding=utf8";
    //sql用户名 和密码 用作连接用
    private static final String USERNAME="root";
    private static final String PWD="cc123nice";
    
    public static Connection connection=null;
    public static PreparedStatement pst =null;
    public static ResultSet rs =null;
    
    /*
     * 得到PreparedStatement减少代码冗余
     */
    public static PreparedStatement getPreparedStatement(String sql,Object[] params) {
        //导入驱动，加载具体驱动类
        try {
            Class.forName("com.mysql.jdbc.Driver");
            //与数据库建立链接
            connection = DriverManager.getConnection(URL, USERNAME, PWD);
            pst=connection.prepareStatement(sql);
            if(params!=null) {
                for(int i=0;i<params.length;i++){
                    pst.setObject(i+1,params[i]);
                }
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return pst;
    }
    /*
     * 最后关闭所有
     */
    public static void closeAll(ResultSet rs,Statement stmt,Connection connection) {
        try {
            if(rs!=null) rs.close();
            if(stmt!=null) stmt.close();
            if(connection!=null) connection.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    
    
    /*
     * 通用的增删改 通过传入的sql和obj数组确认语句
     */
    public static boolean executeUpdate(String sql,Object[] params) {
        try {    
            int count = getPreparedStatement(sql,params).executeUpdate();
            if(count>0)
                return true;
            else 
                return false;
        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }finally {
            closeAll(null, pst, connection);
        }
    }
    
    /*
     * 通用的查询（只能返回到ResultSet）之后必须与具体类型耦合
     */
    public static ResultSet executeQuery(String sql,Object[] params) {
    
        try {
            rs= getPreparedStatement(sql,params).executeQuery();
            return rs;
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
    
}