本节概要
在上一节中我们实现了图书添加的功能，那么这一节主要将实现图书维护的功能，即图书记录的查询、修改和删除。
图书维护界面
首先要先界面弄出来，其他的查询、删除和修改功能都是建立在可视化界面的基础上的。
首先在BookManagePanel.java中添加代码设计界面：
package bookManageSystem.view;
import bookManageSystem.bean.BookTypeBean;
import bookManageSystem.dao.BookDao;
import bookManageSystem.dao.BookTypeDao;
import bookManageSystem.tools.ComponentTools;
import bookManageSystem.tools.SimpleTools;
import javax.swing.*;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import javax.swing.table.DefaultTableModel;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.List;
public class BookManagePanel extends JPanel implements ActionListener, ListSelectionListener {
private ComponentTools componentTools = new ComponentTools();
private SimpleTools simpleTools = new SimpleTools();
private Box totalVBox, funcationHBox, checkHBox, tableHBox, sexRadioButtonHBox, descriptionHBox, buttonHBox,
showContentHBox1, showContentHBox2;
private JComboBox bookTypeComboBox, bookTypeComboBox2;
private JLabel bookManageFuncationLabel, bookNameLabel, bookTypeLabel, idLabel, priceLabel, bookNameLabel2,
bookAuthorLabel, bookTypeLabel2, bookAuthorLabel2, authorSexLabel, bookDescriptionLabel;
private JTextField bookNameTextField, bookNameTextField2, bookAuthorTextField, bookAuthorTextField2, idTextField,
priceTextField;
private JTextArea bookDescriptionTextArea;
private JButton checkButton, resetButton, resetButton2, alterButton, deleteButton;
private ButtonGroup sexButtonGroup;
private JScrollPane tableScrollPanel;
private JRadioButton femaleRadioButton, maleRadioButton;
private JTable table;
private DefaultTableModel tableModel;
BookManagePanel() {
// 为图书维护面板添加控件内容
this.add(this.createBookManageBox());
// 图书类别查询SQL
String getBookTypeSQL = "select * from tb_booktype;";
// 获取所有的图书类别数据
List bookTypeList = new BookTypeDao().getRecordsDataBySql(getBookTypeSQL);
// 提取所有的图书类别名称信息
String[] typeNames = new String[bookTypeList.size()];
for (int i = 0; i < bookTypeList.size(); i++) {
BookTypeBean bookTypeBean = (BookTypeBean) bookTypeList.get(i);
typeNames[i] = bookTypeBean.getBookTypeName();
}
// 初始化下拉列表框中的图书类别信息
componentTools.addComboBoxItems(bookTypeComboBox, typeNames);
componentTools.addComboBoxItems(bookTypeComboBox2, typeNames);
}
/**
* 创建图书维护面板的控件内容
*
* @return 返回一个Box
*/
private Box createBookManageBox() {
totalVBox = Box.createVerticalBox();
funcationHBox = Box.createHorizontalBox();
bookManageFuncationLabel = new JLabel("图书维护功能");
bookManageFuncationLabel.setFont(new Font("微软雅黑", Font.BOLD, 30));
funcationHBox.add(bookManageFuncationLabel);
totalVBox.add(funcationHBox);
totalVBox.add(Box.createVerticalStrut(15));
checkHBox = Box.createHorizontalBox();
bookNameLabel = new JLabel("图书名称：");
bookNameTextField = new JTextField();
bookAuthorLabel = new JLabel("图书作者：");
bookAuthorTextField = new JTextField();
bookTypeLabel = new JLabel("图书类别：");
bookTypeComboBox = new JComboBox();
checkButton = new JButton("查询");
resetButton = new JButton("重置");
checkHBox.add(bookNameLabel);
checkHBox.add(Box.createHorizontalStrut(10));
checkHBox.add(bookNameTextField);
checkHBox.add(Box.createHorizontalStrut(10));
checkHBox.add(bookAuthorLabel);
checkHBox.add(Box.createHorizontalStrut(10));
checkHBox.add(bookAuthorTextField);
checkHBox.add(Box.createHorizontalStrut(10));
checkHBox.add(bookTypeLabel);
checkHBox.add(Box.createHorizontalStrut(10));
checkHBox.add(bookTypeComboBox);
checkHBox.add(Box.createHorizontalStrut(10));
checkHBox.add(checkButton);
checkHBox.add(Box.createHorizontalStrut(10));
checkHBox.add(resetButton);
totalVBox.add(checkHBox);
totalVBox.add(Box.createVerticalStrut(15));
tableHBox = Box.createHorizontalBox();
// 实例化一个滚动面板
tableScrollPanel = new JScrollPane();
// 设置预定义大小
tableScrollPanel.setPreferredSize(new Dimension(700, 250));
tableHBox.add(tableScrollPanel);
totalVBox.add(tableHBox);
totalVBox.add(Box.createVerticalStrut(15));
showContentHBox1 = Box.createHorizontalBox();
idLabel = new JLabel("编号：");
idTextField = new JTextField(5);
idTextField.setEnabled(false);
bookNameLabel2 = new JLabel("图书名称：");
bookNameTextField2 = new JTextField(5);
authorSexLabel = new JLabel("作者性别：");
sexRadioButtonHBox = Box.createHorizontalBox();
femaleRadioButton = new JRadioButton("女");
maleRadioButton = new JRadioButton("男");
sexButtonGroup = new ButtonGroup();
sexButtonGroup.add(femaleRadioButton);
sexButtonGroup.add(maleRadioButton);
sexRadioButtonHBox.add(femaleRadioButton);
sexRadioButtonHBox.add(maleRadioButton);
showContentHBox1.add(idLabel);
showContentHBox1.add(Box.createHorizontalStrut(10));
showContentHBox1.add(idTextField);
showContentHBox1.add(Box.createHorizontalStrut(10));
showContentHBox1.add(bookNameLabel2);
showContentHBox1.add(Box.createHorizontalStrut(10));
showContentHBox1.add(bookNameTextField2);
showContentHBox1.add(Box.createHorizontalStrut(10));
showContentHBox1.add(authorSexLabel);
showContentHBox1.add(Box.createHorizontalStrut(10));
showContentHBox1.add(sexRadioButtonHBox);
totalVBox.add(showContentHBox1);
totalVBox.add(Box.createVerticalStrut(15));
showContentHBox2 = Box.createHorizontalBox();
priceLabel = new JLabel("价格：");
priceTextField = new JTextField(5);
bookAuthorLabel2 = new JLabel("图书作者：");
bookAuthorTextField2 = new JTextField(5);
bookTypeLabel2 = new JLabel("图书类别：");
bookTypeComboBox2 = new JComboBox();
showContentHBox2.add(priceLabel);
showContentHBox2.add(Box.createHorizontalStrut(10));
showContentHBox2.add(priceTextField);
showContentHBox2.add(Box.createHorizontalStrut(10));
showContentHBox2.add(bookAuthorLabel2);
showContentHBox2.add(Box.createHorizontalStrut(10));
showContentHBox2.add(bookAuthorTextField2);
showContentHBox2.add(Box.createHorizontalStrut(10));
showContentHBox2.add(bookTypeLabel2);
showContentHBox2.add(Box.createHorizontalStrut(10));
showContentHBox2.add(bookTypeComboBox2);
totalVBox.add(showContentHBox2);
totalVBox.add(Box.createVerticalStrut(15));
descriptionHBox = Box.createHorizontalBox();
bookDescriptionLabel = new JLabel("图书描述：");
bookDescriptionTextArea = new JTextArea(3, 10);
descriptionHBox.add(bookDescriptionLabel);
descriptionHBox.add(bookDescriptionTextArea);
totalVBox.add(descriptionHBox);
totalVBox.add(Box.createVerticalStrut(15));
buttonHBox = Box.createHorizontalBox();
alterButton = new JButton("修改");
deleteButton = new JButton("删除");
resetButton2 = new JButton("重置");
buttonHBox.add(alterButton);
buttonHBox.add(Box.createHorizontalStrut(100));
buttonHBox.add(deleteButton);
buttonHBox.add(Box.createHorizontalStrut(100));
buttonHBox.add(resetButton2);
totalVBox.add(buttonHBox);
// 批量为各个按钮设置图标
componentTools.setIcons(new JButton[]{alterButton, deleteButton, resetButton2}, new String[]{"src/bookManageSystem" +
"/images/edit.png", "src/bookManageSystem/images/delete.png", "src/bookManageSystem/images/reset.png"});
return totalVBox;
}
@Override
public void actionPerformed(ActionEvent e) {
}
@Override
public void valueChanged(ListSelectionEvent e) {
}
}
运行项目，效果图如下：
初始化表格数据
在完成界面所有控件后，就需要显示表格数据，由于是第一次显示表格数据，所以需要查询所有的表格数据，即初始化表格数据。
根据数据表设计实体类字段，所以实体类BookBean.java的内容如下：
package bookManageSystem.bean;
public class BookBean {
private int bookId;
private String bookName;
private String bookAuthor;
private String bookAuthorSex;
private float bookPrice;
private String bookDescription;
private String bookTypeId;
public BookBean() {
}
public BookBean(int bookId, String bookName, String bookAuthor, String bookAuthorSex, float bookPrice, String bookDescription, String bookTypeId) {
this.bookId = bookId;
this.bookName = bookName;
this.bookAuthor = bookAuthor;
this.bookAuthorSex = bookAuthorSex;
this.bookPrice = bookPrice;
this.bookDescription = bookDescription;
this.bookTypeId = bookTypeId;
}
public int getBookId() {
return bookId;
}
public void setBookId(int bookId) {
this.bookId = bookId;
}
public String getBookName() {
return bookName;
}
public void setBookName(String bookName) {
this.bookName = bookName;
}
public String getBookAuthor() {
return bookAuthor;
}
public void setBookAuthor(String bookAuthor) {
this.bookAuthor = bookAuthor;
}
public String getBookAuthorSex() {
return bookAuthorSex;
}
public void setBookAuthorSex(String bookAuthorSex) {
this.bookAuthorSex = bookAuthorSex;
}
public float getBookPrice() {
return bookPrice;
}
public void setBookPrice(float bookPrice) {
this.bookPrice = bookPrice;
}
public String getBookDescription() {
return bookDescription;
}
public void setBookDescription(String bookDescription) {
this.bookDescription = bookDescription;
}
public String getBookTypeId() {
return bookTypeId;
}
public void setBookTypeId(String bookTypeId) {
this.bookTypeId = bookTypeId;
}
}
接下来就是要查询数据从数据库表中，所以在BookDao.java中写两个方法：
/**
* 操作结果：根据参数sql获取数据库记录数据
*
* @param sql SQL语句
* @return List 返回包含记录Records对象的集合
*/
public List getRecordsDataBySql(String sql) {
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
List list = new ArrayList();
try {
//获得数据的连接
conn = JDBCUtils.getConnection();
//获得Statement对象
stmt = conn.createStatement();
//发送SQL语句
rs = stmt.executeQuery(sql);
while (rs.next()) {
BookBean bookBean = new BookBean();
// 索引是从1开始的
bookBean.setBookId(rs.getInt(1));
bookBean.setBookName(rs.getString(2));
bookBean.setBookAuthor(rs.getString(3));
bookBean.setBookAuthorSex(rs.getString(4));
bookBean.setBookPrice(rs.getFloat(5));
bookBean.setBookDescription(rs.getString(6));
bookBean.setBookTypeId(rs.getString(7));
list.add(bookBean);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCUtils.release(rs, stmt, conn);
}
return list;
}
/**
* 操作结果：将集合转换成数组
*
* @param list 集合
* @return String[][] 二维数组
*/
public String[][] ListToArray(List<BookBean> list) {
String[][] array = new String[list.size()][7];
for (int i = 0; i < list.size(); i++) {
BookBean l = list.get(i);
array[i][0] = String.valueOf(l.getBookId());
array[i][1] = l.getBookName();
array[i][2] = l.getBookAuthor();
array[i][3] = l.getBookAuthorSex();
array[i][4] = String.valueOf(l.getBookPrice());
array[i][5] = l.getBookDescription();
array[i][6] = l.getBookTypeId();
}
return array;
}
从数据库获取数据后需要将其显示在JTable控件中，所以在BookManagePanel.java类中添加一个方法：
/**
* 根据SQL查询得到的表格数据填充创建表格
*
* @param sql SQL语句
* @return 返回填充完成的JTable控件
*/
private JTable createTable(String sql) {
// 获取所有的图书记录并将结果转换成一个二维数组
String[][] rowdatas = new BookDao().ListToArray(new BookDao().getRecordsDataBySql(sql));
// 表头
String[] headers = {"编号", "图书名称", "图书作者", "作者性别", "图书价格", "图书描述", "图书类别"};
// 实例化表格控件
table = new JTable();
// 设置行高
table.setRowHeight(30);
// 将表头和表格内容数据填充到表格数据模型中
tableModel = new DefaultTableModel(rowdatas, headers);
//为表格设置数据模型
table.setModel(tableModel);
// 返回填充完成的表格控件
return table;
}
该方法是将从数据库得到的数据填充到表格中，接下来就是将这个表格显示在界面上了，在createBookManageBox方法中添加这么几行代码，使得表格能够显示在界面上。
// 将表格添加到滚动面板中
tableScrollPanel.setViewportView(this.createTable("select bId,bBookName,bAuthor,bSex,bPrice,bBookDescription," +
"btName from tb_book,tb_booktype where tb_book.btId=tb_booktype.btId;"));
添加位置如下：
在运行项目之前，还要确保你已经添加了连接数据库的第三方加包。
运行程序，结果如下：
图书的查询功能
接着是完成图书的查询功能。
首先要为查询按钮和重置按钮注册事件，其他一些界面要使用的按钮也注册事件。
在BookManagePanel构造器方法中的最后位置添加如下代码注册事件：
// 为按钮注册事件监听器
checkButton.addActionListener(this);
resetButton.addActionListener(this);
alterButton.addActionListener(this);
deleteButton.addActionListener(this);
resetButton2.addActionListener(this);
接着写事件的具体处理代码在actionPerformed方法中：
// “查询”按钮的事件处理
if (e.getSource() == checkButton) {
// 查询SQL
String sql =
"select bId,bBookName,bAuthor,bSex,bPrice,bBookDescription,btName from tb_book,tb_booktype where "
+ "tb_book.btId=tb_booktype.btId ";
// 判断输入是否为空
if (simpleTools.isEmpty(bookNameTextField.getText()) && simpleTools.isEmpty(bookAuthorTextField.getText()) && bookTypeComboBox.getSelectedIndex() < 0) {
sql += " and 1=1;";
} else {
// 用户输入的图书名称
if (bookNameTextField.getText().length() > 0) {
sql += " and bBookName like '%" + bookNameTextField.getText() + "%'";
}
// 用户输入的图书作者
if (bookAuthorTextField.getText().length() > 0) {
sql += " and bAuthor like '%" + bookAuthorTextField.getText() + "%'";
}
// 用户选择的图书类别
String booktype = (String) bookTypeComboBox.getModel().getSelectedItem();
if (simpleTools.isEmpty(booktype)) {
sql += " and btName='" + booktype + "';";
}
}
// 根据组装的SQL获取表格数据并转换成二维数组
String[][] rowdatas = new BookDao().ListToArray(new BookDao().getRecordsDataBySql(sql));
// 表头
String[] headers = {"编号", "图书名称", "图书作者", "作者性别", "图书价格", "图书描述", "图书类别"};
// 重新填充表格数据模型，刷新表格
tableModel.setDataVector(rowdatas, headers);
}
运行程序，效果如下：
查询按钮旁边的重置按钮的事件处理代码如下：
// “重置”按钮的事件处理
if (e.getSource() == resetButton) {
// 查询SQL
String sql =
"select bId,bBookName,bAuthor,bSex,bPrice,bBookDescription,btName from tb_book,tb_booktype where "
+ "tb_book.btId=tb_booktype.btId ";
String[][] rowdatas = new BookDao().ListToArray(new BookDao().getRecordsDataBySql(sql));
String[] headers = {"编号", "图书名称", "图书作者", "作者性别", "图书价格", "图书描述", "图书类别"};
tableModel.setDataVector(rowdatas, headers);
componentTools.reset(bookNameTextField, bookAuthorTextField);
componentTools.reset(bookTypeComboBox);
}
表格选中行显示数据
要想让表格选中行的数据显示下方的各文本框中，首先要注册监听器，在BookManagePanel构造器方法的最后添加如下代码：
// 为表格注册事件监听器
table.getSelectionModel().addListSelectionListener(this);
注册监听器好之后就是写具体的事件处理方法，将valueChanged的代码改成如下：
@Override
public void valueChanged(ListSelectionEvent e) {
// 获取表格所选中行的索引
int getSelectedRowIndex = table.getSelectedRow();
// 判断是用户否选中表格中的某一行
if (getSelectedRowIndex == -1) {
refreshTable();
} else {
// 如果选中表格中的某一行，则将选中行的数据填充到下面的控件中
idTextField.setText((String) table.getValueAt(getSelectedRowIndex, 0));
bookNameTextField2.setText((String) table.getValueAt(getSelectedRowIndex, 1));
boolean b = table.getValueAt(getSelectedRowIndex, 3).equals("男");
if (b) {
maleRadioButton.setSelected(true);
} else {
femaleRadioButton.setSelected(true);
}
priceTextField.setText((String) table.getValueAt(getSelectedRowIndex, 4));
bookAuthorTextField2.setText((String) table.getValueAt(getSelectedRowIndex, 2));
bookTypeComboBox2.setSelectedItem(table.getValueAt(getSelectedRowIndex, 6));
bookDescriptionTextArea.setText((String) table.getValueAt(getSelectedRowIndex, 5));
}
}
并且在BookManagePanel.java类中添加如下方法来刷新表格：
/**
* 刷新表格
*/
private void refreshTable() {
// 条件查询SQL
String sql = "select bId,bBookName,bAuthor,bSex,bPrice,bBookDescription,btName from tb_book,tb_booktype " +
"where tb_book.btId=tb_booktype.btId;";
String[][] rowdatas = new BookDao().ListToArray(new BookDao().getRecordsDataBySql(sql));
String[] headers = {"编号", "图书名称", "图书作者", "作者性别", "图书价格", "图书描述", "图书类别"};
// 重新填充表格数据，刷新表格
tableModel.setDataVector(rowdatas, headers);
}
运行项目，结果如下：
图书的修改功能
实现图书的修改功能，将用户修改的数据更新进数据库并且刷新在表格上滚的显示，在actionPerformed添加如下代码：
// “修改”按钮的事件处理
if (e.getSource() == alterButton) {
String id = idTextField.getText();
String bookName = bookNameTextField2.getText();
String sex = "";
if (femaleRadioButton.isSelected()) {
sex = femaleRadioButton.getText();
} else {
sex = maleRadioButton.getText();
}
Float price = Float.parseFloat(priceTextField.getText());
String bookAuthor = bookAuthorTextField2.getText();
String bookType = (String) bookTypeComboBox2.getModel().getSelectedItem();
String bookDescription = bookDescriptionTextArea.getText();
// 组装修改SQL
String alterSQL =
"update tb_booktype,tb_book set bBookName='" + bookName + "',bAuthor='" + bookAuthor + "',bSex='" + sex + "'," + "bPrice" + "=" + price + "," + "tb_booktype.btName='" + bookType + "',bBookDescription='" + bookDescription + "' where " + "tb_book.btId=tb_booktype" + ".btId " + "and" + " bId=" + id + ";";
// 执行修改操作并返回操作结果
boolean isOK = new BookTypeDao().dataChange(alterSQL);
// 对修改结果进行处理
if (isOK) {
// 修改成功则刷新表格、重置控件内容、弹出提示框
refreshTable();
componentTools.reset(idTextField, bookNameTextField2, priceTextField, bookAuthorTextField2,
bookDescriptionTextArea);
componentTools.reset(sexButtonGroup);
componentTools.reset(bookTypeComboBox2);
JOptionPane.showMessageDialog(null, "修改成功！");
} else {
// 修改失败则也弹出提示框
JOptionPane.showMessageDialog(null, "修改失败！");
}
}
即是对修改按钮的事件处理，也完成了修改的功能。
运行程序，修改数据，结果如下：
图书的删除功能
删除选中的表格行，在actionPerformed方法中添加如下代码：
// “删除”按钮的事件处理
if (e.getSource() == deleteButton) {
// 获取要删除的图书id
String id = idTextField.getText();
// 删除SQL并重置tb_book的主键
String sql1 = "set FOREIGN_KEY_CHECKS=0;";
String deleteSQL = "delete from tb_book where bId=" + id + ";";
String sql2 = "set FOREIGN_KEY_CHECKS=1;";
// 弹出确认框来确认用户是否要删除
int isOK = JOptionPane.showConfirmDialog(null, "是否确认删除？");
// 如果用户点击了确定按钮
if (isOK == JOptionPane.OK_OPTION) {
// 执行删除SQL
new BookDao().dataChange(sql1);
boolean is = new BookDao().dataChange(deleteSQL);
new BookDao().dataChange(sql2);
// 对删除操作结果进行判断
if (is) {
// 删除成功则刷新表格、重置控件内容
refreshTable();
componentTools.reset(idTextField, bookNameTextField2, priceTextField, bookAuthorTextField2,
bookDescriptionTextArea);
componentTools.reset(sexButtonGroup);
componentTools.reset(bookTypeComboBox2);
} else {
// 删除失败也弹出提示框
JOptionPane.showMessageDialog(null, "删除失败！");
}
} else {
return;
}
}
添加代码的位置如下：
运行项目，执行删除操作后，结果如下：
并且第二个重置按钮的事件处理代码如下：
// 第二个“重置”按钮的事件处理
if (e.getSource() == resetButton2) {
// 重置控件内容
componentTools.reset(idTextField, bookNameTextField2, priceTextField, bookAuthorTextField2,
bookDescriptionTextArea);
componentTools.reset(sexButtonGroup);
componentTools.reset(bookTypeComboBox2);
}
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来源：CSDN
作者：二木成林
链接：https://blog.csdn.net/cnds123321/article/details/103886049