首先我们创建好项目，由于我使用的是mysql数据库，就要导入连接mysql的jar包：mysql-connector-java-5.1.3-rc-bin.jar。
接下来，我们就要对项目分好层
这次我们主要讲ui层的编写，其它层的代码就不一 一展示了，有需要的可以在此处下载 https://pan.baidu.com/s/1uYPkjUOI_NLL6ktkAdq5EQ
主界面的步骤都在以下的代码中，在代码中对每一步操作都已注释了
import java.awt.BorderLayout; import java.awt.event.FocusAdapter; import java.awt.event.FocusEvent; import java.awt.event.FocusListener; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; import java.util.Set; import java.util.TreeSet; import java.util.Vector; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JOptionPane; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.JTextField; import javax.swing.ListSelectionModel; import javax.swing.event.TableModelEvent; import javax.swing.event.TableModelListener; import javax.swing.table.DefaultTableModel; import javax.swing.table.TableColumn; import pojo.Student; import pojo.StudentConstant; import service.StudentService; import service.impl.StudentServiceImpl; import util.DataConversion; public class JTableTest extends JFrame{ private JPanel jp1=new JPanel(); private JPanel jp2=new JPanel(); private JPanel jp3=new JPanel(); private JTable jt =null; private JButton select =new JButton("查询"); private JButton delete =new JButton("删除"); private JButton update =new JButton("确认修改"); private JButton add =new JButton("增加"); private JButton recover =new JButton("恢复"); private JTextField jtf=new JTextField(20); private JScrollPane jsp=null; private DefaultTableModel dtm=null; private StudentService ss=new StudentServiceImpl(); private List<Student> list=null; private Vector<Vector<String>> vec1; private Vector<String> vec2=null; private String st=null; //===========保存修改后的列名===================== private Set<Integer> li=null; public JTableTest() { this.setTitle("学生表"); this.setSize(500, 600); this.setLocationRelativeTo(null); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); this.setResizable(false); //============设置一个保存表头的Vector========== vec2=new Vector<String>(); vec2.add("学号"); vec2.add("编号"); vec2.add("姓名"); vec2.add("分数");
list=ss.selectStudentAll();
// vec1=DataConversion.zhuanHuan(list);
//============为表模型设置数据和表头============= dtm=new DefaultTableModel(vec1,vec2); jt=new JTable(){
//===============设置数据是否可编辑================ public boolean isCellEditable(int row, int column) {
//==============姓名、分数可编辑================== if(column==StudentConstant.SNAME||column==StudentConstant.SCORE) return true; else return false; } }; jt.setModel(dtm);
//===========设置表的点击方式为只可单选=============== jt.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
//================设置列不可移动============= jt.getTableHeader().setReorderingAllowed(false);
//===============设置所以列不可调整大小=================== jt.getTableHeader().setResizingAllowed(false); //===============隐藏学号这一列因为学号不可被客户查看，但我们对数据的增删改查需要用到主键，所以隐藏=================== TableColumn tc=jt.getColumnModel().getColumn(0); tc.setMaxWidth(0); tc.setMinWidth(0); tc.setPreferredWidth(0); tc.setResizable(false); li=new TreeSet<Integer>(); //===========查询========================== select.addMouseListener(new MouseAdapter() { public void mouseClicked(MouseEvent e) { String sname=jtf.getText(); list=new ArrayList<Student>(); list=ss.selectStudentBySname(sname); flush(); } }); //===============增加===================== add.addMouseListener(new MouseAdapter() { public void mouseClicked(MouseEvent e) {
//=============new一个新的增加窗口============= AddJFrame ad=new AddJFrame();
//=============当主窗体获得焦点时刷新一下Jtable============ add.addFocusListener(new FocusAdapter() { public void focusGained(FocusEvent e) { list=ss.selectStudentAll(); flush(); } }); } }); //================删除===================== delete.addMouseListener(new MouseAdapter() { public void mouseClicked(MouseEvent e) { int i=jt.getSelectedRow(); //=======判断是否选中不选中不弹窗口============== if(i!=-1) { String s=(String) dtm.getValueAt(i, StudentConstant.SID);
//=================弹确认删除窗口================================== int t=JOptionPane.showConfirmDialog(JTableTest.this, "是否删除该数据"); switch (t) { case JOptionPane.YES_OPTION: ss.deleteStudent(Integer.parseInt(s)); list=ss.selectStudentAll(); flush(); } } } }); //=================修改数据==================== //==================获取修改前的数据=============== jt.addMouseListener(new MouseAdapter() { public void mouseClicked(MouseEvent e) { int i=jt.getSelectedRow(); int j=jt.getSelectedColumn(); st = (String) jt.getValueAt(i, j); } });
dtm.addTableModelListener(new TableModelListener() { public void tableChanged(TableModelEvent e) { int i=jt.getSelectedRow(); int j=jt.getSelectedColumn(); String s= (String) jt.getValueAt(i, j);
//=================判断修改后数据有没有发生改变=============== if(e.getType()==TableModelEvent.UPDATE) { if(st!=null&!st.equals(s)) {
//================改变后就加入set集合里，注意此处使用set集合重复修改的也只会提交一次可以提高性能===================== li.add(i); } } } }); //================确认修改============ update.addMouseListener(new MouseAdapter() { public void mouseClicked(MouseEvent e) { int t=JOptionPane.showConfirmDialog(JTableTest.this, "你确认修改吗，修改后不可恢复"); switch (t) {
//========================确认修改，在数据库中修改============================ case JOptionPane.YES_OPTION: for (Integer i : li) { Student s=new Student(); String ssid=(String) jt.getValueAt(i, StudentConstant.SID); int sid=Integer.parseInt(ssid); String sname=(String) jt.getValueAt(i, StudentConstant.SNAME); int score=Integer.parseInt((String) jt.getValueAt(i, StudentConstant.SCORE)); s.setSid(sid); s.setSname(sname); s.setScore(score); ss.upadteStudent(s); } list=ss.selectStudentAll(); flush(); } } }); //===================恢复==================== recover.addMouseListener(new MouseAdapter() { public void mouseClicked(MouseEvent e) { int t=JOptionPane.showConfirmDialog(JTableTest.this, "你确认恢复吗，只可以恢复到上一次确认修改后的位置"); switch (t) { case JOptionPane.YES_OPTION:
//==============确认修改之前只是在表上修改了数据没有对数据库进行操作，点击恢复只需要重新查询数据库刷新界面======================== list=ss.selectStudentAll(); flush(); } } }); jsp=new JScrollPane(jt); jp1.add(jtf); jp1.add(select); jp2.add(jsp); jp3.add(add); jp3.add(delete); jp3.add(recover); jp3.add(update); this.getContentPane().add(jp1, BorderLayout.NORTH); this.getContentPane().add(jp2); this.getContentPane().add(jp3, BorderLayout.SOUTH); this.setVisible(true); } private void flush() {
//==============改变模型的数据==================== vec1=DataConversion.zhuanHuan(list); dtm=new DefaultTableModel(vec1,vec2); jt.setModel(dtm);
//======每次刷新的时候隐藏第一列================= TableColumn tc=jt.getColumnModel().getColumn(0); tc.setMaxWidth(0); tc.setMinWidth(0); tc.setPreferredWidth(0); tc.setResizable(false); } public static void main(String[] args) throws SQLException { new JTableTest(); } }
以下为增加功能的弹窗
package ui; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JTextField; import pojo.Student; import service.StudentService; import service.impl.StudentServiceImpl; public class AddJFrame extends JFrame{ private JLabel sname=new JLabel("姓名"); private JTextField jtf1=new JTextField(); private JLabel score=new JLabel("分数"); private JTextField jtf2=new JTextField(); private JButton jb=new JButton("保存"); private StudentService ss=new StudentServiceImpl(); public AddJFrame() { this.setTitle("新增"); this.setSize(400, 300); this.setLocationRelativeTo(null); this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); this.setResizable(false); this.setLayout(null); sname.setBounds(120, 100, 55, 20); this.add(sname); jtf1.setBounds(180, 100, 90, 20); this.add(jtf1); score.setBounds(120, 145, 55, 20); this.add(score); jtf2.setBounds(180, 145, 90, 20); this.add(jtf2); jb.setBounds(160, 195, 90, 20); jb.addMouseListener(new MouseAdapter() { public void mouseClicked(MouseEvent e) { Student s=new Student(); //==========非空判断=========== String name=jtf1.getText(); String scc=jtf2.getText(); if(name.length()!=0&&scc.length()!=-1) { int sc =Integer.parseInt(scc); s.setSname(name); s.setScore(sc); ss.addStudent(s); AddJFrame.this.dispose(); } } }); this.add(jb); this.setVisible(true); } }
总结：在对学生表的删除功能中，我在一开始写的时候并没有判断有没有选中，这一点要注意，因为不判断的话，在String s=(String) dtm.getValueAt(i, StudentConstant.SID)；这一行代码中就会报数组越界异常，因为没有选中的时候i为-1.
还有就是在增加窗口的非空判断，如果没有判断输入空时就会报数字转换异常，由于在写的时候比较疏忽也就没有对成绩进行进行判断，希望大家谅解。
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