Java 一個簡單的數據庫操作示例

1.　　主窗體界面，代碼如下：

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class BoxLayoutFrame extends JFrame {
    private JTextField textField;
    private JTextArea textArea;
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        BoxLayoutFrame frame=new BoxLayoutFrame();
        frame.setVisible(true);    

    }
    public BoxLayoutFrame() {
        super();
        setTitle("箱式布局管理界面");
        setBounds(360,260,360,320);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Container cp=getContentPane();
        Box topicBox=Box.createHorizontalBox();    //創建一個水平箱容器
        cp.add(topicBox, BorderLayout.NORTH);    //添加到窗體中的最北部
        topicBox.add(Box.createHorizontalStrut(5));    //添加一個5像素的水平支柱
        JLabel topicLabel=new JLabel("主題:");    //創建標簽topicLabel
        topicBox.add(topicLabel);                //添加到水平箱容器中
        topicBox.add(Box.createHorizontalStrut(5));    //添加一個5像素的水平支柱
        textField=new JTextField(80);            //創建文本框
        topicBox.add(textField);                //添加到水平容器中
        Box box=Box.createVerticalBox();        //創建一個垂直箱容器
        cp.add(box, BorderLayout.CENTER);        //添加到窗體中
        box.add(Box.createVerticalStrut(5));    //添加一個5像素的垂直支柱
        Box contentBox=Box.createHorizontalBox();    //創建一個水平箱容器
        contentBox.setAlignmentX(1);            //設置組件的水平調整值，靠右對齊
        box.add(contentBox);                    //添加到垂直容器中
        contentBox.add(Box.createHorizontalStrut(5));    //添加一個5像素的水平支柱
        JLabel contentLabel=new JLabel("內容:");    //定義標簽contentLabel
        contentLabel.setAlignmentY(0);            //設置組件的垂直調整值，靠上方對齊
        contentBox.add(contentLabel);            //添加到水平箱容器中
        contentBox.add(Box.createHorizontalStrut(5));    //添加一個5像素
        JScrollPane scrollPane=new JScrollPane();    //創建滾動面板
        scrollPane.setAlignmentY(0);            //設置組件的垂直調整值，向上對齊
        contentBox.add(scrollPane);                //將滾動面板添加到contentBox中
        textArea=new JTextArea();                //創建文本框textArea
        textArea.setLineWrap(true);                //允許自動換行
        scrollPane.setViewportView(textArea);    //文本框添加到滾動面板scrollPane
        box.add(Box.createVerticalStrut(5));    //添加一個5像素高的垂直支柱
        
        Box bottomBox=Box.createHorizontalBox();
        bottomBox.setAlignmentX(1);
        box.add(bottomBox,BorderLayout.SOUTH);
        JButton viewButton=new JButton("瀏覽記錄");
        bottomBox.add(viewButton);
        viewButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                SelectFrame sframe=new SelectFrame(BoxLayoutFrame.this);
                sframe.setVisible(true);
            }
        });
        
        JButton button=new JButton("確定");        //創建一個按鈕button
        button.setAlignmentX(1);                //設置組件的水平調整值，靠右對齊
        //box.add(button);                        //按鈕添加到垂直箱容器
        bottomBox.add(button);
        
        button.addActionListener(new ActionListener() {
            public void actionPerformed(final ActionEvent arg1) {
                //System.exit(0);
                if(textField.getText().length()==0) {//如果文本框無輸入信息則不作任何處理
                    
                }
                if(!textField.getText().equals("")) {
                TbNews tbs=new TbNews();
                tbs.setTopicId(textField.getText());
                tbs.setContentTxt(textArea.getText());
                boolean res =DbOperation.getInstance().addTbNews(tbs);
                if (res==true) {
                    textField.setText(null);
                    textArea.setText(null);
                }  }
            }
        });    
    }

}

2.　　數據庫連接類，本示例數據庫是SQL Server2008 R2。代碼如下：

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

public  class DbTool {
    private static Connection conn=null;    //創建Connection對象
    public static Connection getConn() {
        try {
            Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");    //加載SQL Server數據庫驅動
        } catch(ClassNotFoundException e) {
            e.printStackTrace();
        }
        //指定連接數據庫的URL
        String url="jdbc:sqlserver://localhost:1433;databaseName=SRM";
        String user="sa";                //指定連接數據庫的用戶名
        String passWord="1111";            //指定連接數據庫的密碼
        try {
            conn=DriverManager.getConnection(url,user,passWord);
            if(conn!=null) {                //如果Connection實例不為空
                //System.out.println("數據庫連接成功");  //提示信息
            }
            
            /*
             //加載MySQL數據庫的連接
             Class.forName("com.mysql.jdbc.Driver"); //加載MySQL數據庫驅動
             String url="jdbc:mysql://localhost:3306/SRM";
             String user="sa";
             String passWord="1111";
             conn=DriverManager.getConnection(url,user,passWord);
             if(conn!=null){
             
             }
             
             //加載Oracle數據庫的連接
             Class.forName("oracle.jdbc.driver.OracleDriver");// 加載Oracle驅動程序
             String url = "jdbc:oracle:" + "thin:@127.0.0.1:1521:SRM";// 127.0.0.1是本機地址，SRM是精簡版Oracle的默認數據庫名
             String user = "sa";// 用戶名
             String password = "1111";// 你安裝時選設置的密碼
             conn = DriverManager.getConnection(url, user, password);// 獲取連接
             */
        } catch(SQLException e) {
            e.printStackTrace();
        }
        return conn;
    }
}

3.　　數據庫操作類，示例代碼如下：

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

public class DbOperation {
    private static  DbOperation instance = null;   
    public static DbOperation getInstance() { //返回DbOperation類實例的靜態方法,單例模式！！！！
        if (instance == null) {
            instance = new DbOperation();
        }    
        return instance;
    }
    public boolean addTbNews(TbNews tns) {  //添加數據方法
        Connection conn=null;
        boolean result=false;
        try {
            conn=DbTool.getConn();    //建立與數據庫的連接
            String sqlInsert="INSERT INTO tbNews(topicId,contentTxt)VALUES(?,?)";
            PreparedStatement stm=conn.prepareStatement(sqlInsert);
            stm.setString(1, tns.getTopicId());
            stm.setString(2, tns.getContentTxt());
            int i=stm.executeUpdate();
            if (i==1) {
                result=true;
            }
        }catch(SQLException e) {
            e.printStackTrace();
        }finally {
            try {
                conn.close();
            }catch (SQLException e) {
                e.printStackTrace();
            }
        }
        return result;
    }
    
    public Vector<TbNews> queryTbNews(){     //返回Vector類型方式查詢數據
        Vector<TbNews> list =new Vector<TbNews>();
        Connection conn=null;
        try {
            conn=DbTool.getConn();
            Statement stmt=conn.createStatement();
            String querySql="select * from TbNews";
            ResultSet rs=stmt.executeQuery(querySql);
            while(rs.next()) {
                TbNews tbs=new TbNews();
                tbs.setTopicId(rs.getString(1));
                tbs.setContentTxt(rs.getString(2));
                list.add(tbs);
            }
        } catch(Exception e) {
            e.printStackTrace();
        } finally {
            try {
                conn.close();
            } catch(SQLException e) {
                e.printStackTrace();
            }
        }
        return list;
    }
    
    public List<String> selectTbNews(){        //查詢數據方法
        List<String> tbsList=new ArrayList<String>();
        Connection conn=null;
        try {
            conn=DbTool.getConn();
            Statement stmt=conn.createStatement();
            String selectSql="select * from TbNews";    
            ResultSet rs=stmt.executeQuery(selectSql);    //執行SQL並返回結果集
            while(rs.next()) {    
                String tbs=rs.getString("topicId")+","+rs.getString("contentTxt");
                tbsList.add(tbs);
            }
        } catch(Exception e) {
            e.printStackTrace();
        } finally {
            try {
                conn.close();        //關閉連接
            }catch(SQLException e) {
                e.printStackTrace();
            }
        }
        return tbsList;
    }
}

/*

package 數據庫_向數據庫插入數據;

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

public class DatabaseConnection {
    private static Connection conn = null;
    public static Connection getCon() {
        try {
            Class.forName("com.mysql.jdbc.Driver"); //加載數據庫連接驅動
            String user = "root";
            String psw = "XXX";  //XXX為自己的數據庫的密碼
            String url = "jdbc:mysql://localhost:3306/ZZZ";                   //ZZZ為連接的名字
            conn = DriverManager.getConnection(url, user, psw);  //獲取連接
        } catch (Exception e) {
            System.out.println("連接數據庫失敗");
            e.printStackTrace();
        }
        return conn;
    }

}


package 數據庫_向數據庫插入數據;

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

//EmployeeOperation類用於操作數據庫，以下的編寫方法是JAVA軟件編程的一種設計模式，稱為！！！！！ 單例模式，！！！！！！！
//方法中先判斷該類的對象是否為空，只有為空才創建(new) ,因此保證該對象在程序中永遠是唯一的，可以避免重復創建對象造成的系統內存被過多占用
public class EmployeeOperation {
    private static  EmployeeOperation instance = null;
    
    public static EmployeeOperation getInstance() { //返回EmployeeOperation類實例的靜態方法,單例模式！！！！
        if (instance == null) {
            instance = new EmployeeOperation();
        }    
        return instance;
    }
    
    public boolean saveEmployee(Employee emp) {   //向數據庫中加入數據
        boolean result = false;
        Connection conn = null;
        try {
            
        conn = DatabaseConnection.getCon();  //建立數據庫連接
        String sqlInset = "insert into company.tb_employee(empId, empName, empAge, empSex) values(?, ?, ?, ?)";
        PreparedStatement stmt = conn.prepareStatement(sqlInset);   //會拋出異常
        
        stmt.setInt(1, emp.getEmpId());         //設置SQL語句第一個“？”的值
        stmt.setString(2, emp.getEmpName());    //設置SQL語句第二個“？”的值
        stmt.setInt(3, emp.getEmpAge());        //設置SQL語句第三個“？”的值
        stmt.setString(4, emp.getEmpSex());     //設置SQL語句第四個“？”的值
        int i = stmt.executeUpdate();            //執行插入數據操作，返回影響的行數
        if (i == 1) {
            result = true;
        }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally { //finally的用處是不管程序是否出現異常，都要執行finally語句，所以在此處關閉連接
            try {
                conn.close(); //打開一個Connection連接后，最后一定要調用它的close（）方法關閉連接，以釋放系統資源及數據庫資源
            } catch(SQLException e) {
                e.printStackTrace();
            }
        }
        
        return result;
        
    }
    
    
    public List<Employee> selectEmployee() {       //從數據庫中查詢所需數據
        List<Employee> empList = new ArrayList<Employee>();
        Connection conn = null;
        try {
            conn = DatabaseConnection.getCon();
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery("select * from company.tb_employee");//執行SQL並返回結果集
            while (rs.next()) {
                Employee emp = new Employee();
                emp.setEmpId(rs.getInt("empId"));   //從結果集rs中獲取內容時，若為字符串類型的，用rs.getString("string")方法
                emp.setEmpName(rs.getString("empName"));   //其中str為想要從    數據庫的    表    中獲取的信息
                emp.setEmpAge(rs.getInt("empAge"));  //若為int類型，用rs.getInt(number);
                emp.setEmpSex(rs.getString("empSex"));
                empList.add(emp);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                conn.close();                                         //關閉連接
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return empList;                                             //返回結果
    }
    
    
    public boolean updateEmployee(Employee emp) { //根據員工的編號更改員工的年齡信息
        boolean result = false;
        Connection conn = null;
        try {
            conn = DatabaseConnection.getCon();
            String sql = "update company.tb_employee set empAge=? where empId=?";  //update語句
            PreparedStatement stmt = conn.prepareStatement(sql);
            stmt.setInt(1, emp.getEmpAge());                //設置SQL語句第一個"?"的參數值
            stmt.setInt(2, emp.getEmpId());                    //設置SQL語句第二個"?"的參數值    
            int flag = stmt.executeUpdate();                //執行修改操作，返回影響的行數
            if (flag == 1) {                                //修改成功返回true
                result = true;
            }
        } catch(Exception e) {
            e.printStackTrace();
        } finally {
            try {
                conn.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return result;
    }
    
    public boolean deleteEmployeeById(Employee emp) {
        boolean result = false;
        Connection conn = null;
        try {
            conn = DatabaseConnection.getCon();
            String sql = "delete from company.tb_employee where empId = ?";
            PreparedStatement stmt = conn.prepareStatement(sql);
            stmt.setInt(1, emp.getEmpId());
            int i = stmt.executeUpdate();
            if (i == 1) {
                result = true;
            } 
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                conn.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return result;
    }

}


package 數據庫_向數據庫插入數據;

public class MainTest {
    public static void main(String[] args) {    //測試向數據庫的表中插入元素的方法
        Employee emp = new Employee();
        emp.setEmpId(2);
        emp.setEmpName("LILEI");
        emp.setEmpAge(33);
        emp.setEmpSex("male");
        boolean res = EmployeeOperation.getInstance().saveEmployee(emp);
        if (res == true) {
            System.out.println("向company.tb_employee表中插入數據成功");
        } else {
            System.out.println("向company.tb_employee表中插入數據失敗");
        }
    }

}

package 數據庫_向數據庫插入數據;

import java.util.List;

public class SelectMainTest {     //測試從數據庫中獲取數據的方法
    public static void main(String[] args) {
        List<Employee> empList = EmployeeOperation.getInstance().selectEmployee();
        System.out.println("員工ID\t員工姓名\t員工年齡\t員工性別");
        for (Employee emp : empList) {
            System.out.print(emp.getEmpId() + "\t" + emp.getEmpName() + "\t" + emp.getEmpAge() + "\t" + emp.getEmpSex());
            System.out.println();
        }
    }

}

package 數據庫_向數據庫插入數據;

import java.util.List;

public class UpdateMainTest {    //根據員工的id修改員工年齡的方法
    public static void main(String[] args) {
        List<Employee> empList = EmployeeOperation.getInstance().selectEmployee();
        System.out.println("員工ID");
        for (Employee emp : empList) {
            System.out.println(emp.getEmpId());
        }
        Employee emp = new Employee();
        emp.setEmpId(2);
        emp.setEmpAge(50);
        boolean res = EmployeeOperation.getInstance().updateEmployee(emp);
        if (res == true) {
            System.out.println("編號為2的員工的年齡修改成功");
        } else {
            System.out.println("編號為2的員工的年齡修改失敗");
        }
        
    }

}

package 數據庫_向數據庫插入數據;

public class DeleteMainTest {
    public static void main(String[] args) {   //測試刪除對應id的員工的方法
        Employee emp = new Employee();
        emp.setEmpId(1);
        boolean res = EmployeeOperation.getInstance().deleteEmployeeById(emp);
        if (res == true) {
            System.out.println("成功刪除id為1的員工");
        } else {
            System.out.println("未能成功刪除id為1的員工");
        }
    }

}

//////
 
 對於ResultSet取得結果后，我們可以使用Vector二維數據存儲，然后再利用new DefaultTableModel（vector，vector）來構造表格模型
Vector<Vector<Object>> list = new Vector<Vector<Object>>();
while(result.next())
{
Vector<Object> vTemp = new Vector<Object>();
vTemp.add(result.getInt(1));//ID
vTemp.add(result.getString(2));//姓名
vTemp.add(result.getInt(3));//隊
vTemp.add(result.getString(4));//手機
if(result.getInt(5) == 0){
         vTemp.add("否");//是否已經繳費
}
else{
vTemp.add("是");//是否已經繳費
}
vTemp.add(result.getInt(6));//欠費
list.add(vTemp);
}
Vector<String> columns = new Vector<String>();
columns.add("ID");
columns.add("姓名");
columns.add("隊");
columns.add("手機");
columns.add("已繳費");
columns.add("欠費");
tableModel = new DefaultTableModel(list,columns);
table.setModel(tableModel);



import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.Vector;
 
import javax.swing.JOptionPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
 
public class Utilities {

     // 功能：實現結果集的表格顯示

    public static void displayResultSet(JTable table, ResultSet rs)
            throws SQLException {
        //
        rs.beforeFirst();// 指針移到第一條記錄前面
        boolean hasRecords = rs.next();
 
        if (!hasRecords) { // 記錄集為空，提示一條消息
            JOptionPane.showMessageDialog(table, "無相關記錄", "Check your input!",
                    JOptionPane.ERROR_MESSAGE);
            return;
        }
 
        Vector<String> columnHeads = new Vector<String>();// 用於存儲表頭字段(列名)
        Vector<Vector> rows = new Vector<Vector>();// 用於存儲記錄行
        try {
            // 獲取字段的名稱
            ResultSetMetaData rsmd = rs.getMetaData();
            for (int i = 1; i <= rsmd.getColumnCount(); ++i)
                columnHeads.addElement(rsmd.getColumnName(i));
 
            do {// 獲取記錄集
                rows.addElement(getNextRow(rs, rsmd));
            } while (rs.next());
            // 建立相應的TableModel,並將TableModel應用到Table中顯示出來
            DefaultTableModel model = new DefaultTableModel(rows, columnHeads);
            table.setModel(model);
            return;
        } catch (SQLException exc) {
            JOptionPane.showMessageDialog(table, exc.toString(),
                    "Check your input!", JOptionPane.ERROR_MESSAGE);
            return;
        }
    }
 
//
//      被displayResultSet(JTable table, ResultSet rs)調用, 以Vector形式返回一個記錄行

    private static Vector getNextRow(ResultSet rs, ResultSetMetaData rsmd)
            throws SQLException {
        Vector<String> currentRow = new Vector<String>();
        for (int i = 1; i <= rsmd.getColumnCount(); ++i)
            currentRow.addElement(rs.getString(i));
        return currentRow; // 返回一條記錄
    }
 
}

*/

4.　　實體類，示例代碼如下：

public class TbNews {
    private String topicId;
    private String contentTxt;
    public TbNews() {
        
    }
    public TbNews(String topicId,String contentTxt) {
        this.topicId=topicId;
        this.contentTxt=contentTxt;
    }
    
    public String getTopicId() {
        return topicId;
    }
    public void setTopicId(String topicId) {
        this.topicId=topicId;
    }
    public String getContentTxt() {
        return contentTxt;
    }
    public void setContentTxt(String contentTxt) {
        this.contentTxt=contentTxt;
    }
}

5.　　瀏覽記錄，代碼如下：

import java.awt.BorderLayout;
import java.awt.Container;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.List;
import java.util.Vector;

import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;

public class SelectFrame extends JDialog {
    Thread t;
    private JTable table;    
    private DefaultTableModel tableModel;
    public SelectFrame(BoxLayoutFrame frame) {
        super(frame,"瀏覽記錄",true);
        setBounds(380,300,300,260);
        Container cp=getContentPane();
        
        /*
        Vector<String> columns=new Vector<String>();
        columns.add("topicId");
        columns.add("contentTxt");
        Vector<Vector<TbNews>> list = new Vector<Vector<TbNews>>();
        list.add(DbOperation.getInstance().queryTbNews());
        tableModel=new DefaultTableModel(list,columns);
        //table=new JTable(tableModel);
        table=new JTable();
        table.setModel(tableModel);
        */
        String[] columns= {"topicId","contentTxt"};
        tableModel=new DefaultTableModel(columns,0);
        List<String> tbs=DbOperation.getInstance().selectTbNews();
        for(String info:tbs) {
            String[] args=info.split(",");
            tableModel.addRow(args);
        }
        table=new JTable();
        table.setModel(tableModel);
        
        final JScrollPane scrollPane=new JScrollPane();
        cp.add(scrollPane, BorderLayout.CENTER);
        scrollPane.setViewportView(table);
    }
}