java swing

以前接触java感觉其在桌面开发上,总是不太方便,没有一个好的拖拽界面布局工具,可以快速构建窗体. 最近学习了一下NetBeans IDE 8.1,感觉其窗体设计工具还是很不错的 , 就尝试一下做了一个窗体应用程序. 总体下来,感觉和winform开发相差也不大,只是一些具体的设置或者语法有些差异,可以通过查阅相关资料进行掌握:

1 应用结构

新建一个java应用程序JavaApp,并创建相关的包及文件,其中简单实现了一个登录界面(JDBC 访问MYSQL数据库),登录成功后跳转到主界面.在主界面上单击菜单,可以打开子窗体.java swing自带的JTabbedPane没有显示关闭按钮的功能,这里在com.mkmis.controls包下自定义了一个TabbedPane控件,可以实现带关闭按钮的页签面板.应用结构如下图所示:

2 登陆界面设计

在IDE中新建一个Login的JFrame窗体,单击[设计]视图,可以将组件面板中的相关控件拖放到界面上,和Vistual Studio的操作差别不大,就是界面显示效果较差,不及Vistual Studio.用户名文本框用的文本字段,密码框用的是口令字段控件.登录和退出按钮用的是按钮控件.

设计完成后,单击运行按钮,界面效果如下图所示:

3 相关属性设置

Java Swing的很多属性设置用的方法,而NET用的属性.例如设置窗体标题,java swing用的是setTitle().另外窗体居中用的是setLocationRelativeTo(getOwner()). 获取文本框的值为getText()方法,如下代码所示:

1     public Login() {        2         initComponents();3         setTitle("登录");   4         setDefaultCloseOperation(EXIT_ON_CLOSE);   5         setVisible(true);     6         setResizable(false);   7         setLocationRelativeTo(getOwner()); //居中显示8 9     }

 1  private void btnLoginActionPerformed(java.awt.event.ActionEvent evt) {                                          2     // TODO add your handling code here: 3     if(this.txtUserName.getText()!="" && this.txtPWD.getText().toString()!="") 4     { 5         Connection conn = DBConnection.getConnection(); 6         PreparedStatement ps = null; 7         ResultSet rs = null; 8         try { 9             ps = conn.prepareStatement(　　　　　　　　　"select * from users where UserName = ? and password = ?");10             ps.setString(1,this.txtUserName.getText());// 11             ps.setString(2, this.txtPWD.getText());12             rs = ps.executeQuery();13             while (rs.next()) {14                 User user = new User();15                 user.setId(rs.getInt("id"));16                 user.setUsername(rs.getString("UserName"));17                 user.setPassword(rs.getString("password"));18                 19                 System.out.println(user.toString());20                 //跳转页面21                 FrameMain frm=new FrameMain(user.getUsername());22                 frm.setVisible(true);23                 this.dispose();//关闭当前窗体24                                 25             }26         } catch (SQLException e) {27             e.printStackTrace();28         } finally {29             DBConnection.closeResultSet(rs);30             DBConnection.closeStatement(ps);31             DBConnection.closeConnection(conn);32         }33             34      }35  }                                       

 显示一个窗体是设置其setVisiable(true);关闭一个窗体用的dispose();在登录界面想着输完用户名和密码后,按enter键可以自动登录,在网上搜下,发现了一个变通的方法,就是监听密码框的keypressed事件,当然需要验证一下用户名和密码是否为空(此处未加验证!),如下代码所示:

1    private void txtPWDKeyPressed(java.awt.event.KeyEvent evt) {                                  2         // TODO add your handling code here:3         if(evt.getKeyCode()==KeyEvent.VK_ENTER)4         {5             //调用登录事件6             btnLoginActionPerformed(null);7             8         }9     }        

 4 主界面

登录成功后,单击左边的树叶节点,通过反射动态实例化窗体(实际上菜单应该从数据库加载)并显示,主界面如下:

 图表控件用的是JFreeChart控件,默认显示中文有乱码情况,需要设置显示中文处的字体进行解决.另外设置主界面显示最大化的代码为this.setExtendedState(this.getExtendedState()|JFrame.MAXMIZED_BOTH).为了让某个控件可以随着窗体大小变化而自动调整,需要设置其水平和垂直自动调整.

 1     public FrameMain(){ 2         initComponents(); 3          setLocationRelativeTo(getOwner()); //居中显示 4          this.setExtendedState(this.getExtendedState()|JFrame.MAXIMIZED_BOTH );　　　　　　　//最大化 window 5          LoadTree(); 6        7     } 8     public FrameMain(String uname){ 9         initComponents();10          setLocationRelativeTo(getOwner()); //居中显示11          this.setExtendedState(this.getExtendedState()|JFrame.MAXIMIZED_BOTH );12          LoadTree();13          this.lblUser.setText("欢迎 "+uname+ " 登录!");14       15     }

 主界面在初始化时,调用LoadTree方法来填充左边的菜单树,如下所示:

 1     private void LoadTree() 2     { 3         //自定义控件,支持关闭按钮 4         jTabbedPane1.setCloseButtonEnabled(true); 5   6         DefaultMutableTreeNode node1 = new DefaultMutableTreeNode("软件部"); 7         node1.add(new DefaultMutableTreeNode("产品部")); 8         node1.add(new DefaultMutableTreeNode("测试部")); 9         node1.add(new DefaultMutableTreeNode("设计部"));10  11         DefaultMutableTreeNode node2 = new DefaultMutableTreeNode("销售部");12         node2.add(new DefaultMutableTreeNode("jack"));13         node2.add(new DefaultMutableTreeNode("Lily"));14         node2.add(new DefaultMutableTreeNode("Smith"));15  16         DefaultMutableTreeNode top = new DefaultMutableTreeNode("职员管理");17            18        19         top.add(new DefaultMutableTreeNode("总经理"));20         top.add(node1);21         top.add(node2);22        23         //JTree tree=new JTree(top);       24         DefaultTreeModel model = new DefaultTreeModel (top);     25         this.jTree1.setModel(model);26        //jTree1.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION)      27        //set jframe icon28        try29            30        {31        Image icon= ImageIO.read(this.getClass().getResource("/images/Icon.png"));32        tabIcon = createImageIcon("/images/Icon.png", "tab icon");33       34        this.setIconImage(icon);35        }36        catch(IOException ex)37        {38            39            System.out.println(ex);40                    41        }42     43     }

 在Tree的值变化事件中,通过class.forName()和 cls.newInstance()反射动态实例化窗体,代码如下:

 1     private void jTree1ValueChanged(javax.swing.event.TreeSelectionEvent evt) {                                     2         // TODO add your handling code here: 3       4        DefaultMutableTreeNode node = (DefaultMutableTreeNode) 　　　　　　　　jTree1.getLastSelectedPathComponent(); 5  6         if (node == null){ 7             //Nothing is selected.   8              return; 9         }10 11         Object nodeInfo = node.getUserObject();12         String item = (String) nodeInfo;13 14         if (node.isLeaf()) {15             String item1 = (String) nodeInfo;16             // this.setTitle(item1);17             //File f = new File("client.jar");18             //URLClassLoader cl = new URLClassLoader(new URL[]{f.toURI().toURL(), null});19             //Class<?> clazz = cl.loadClass("epicurus.Client");20             //Method main = clazz.getMethod("main", String[].class);21             //main.invoke(null, new Object[]{new String[]{}});22             try {23                 Class cls = Class.forName("com.mkmis.forms.JIFrame1");24                 javax.swing.JInternalFrame frm =　　　　　　　　　　　　　　　　(javax.swing.JInternalFrame) cls.newInstance();25                  frm.setVisible(true);26 27                 //jTabbedPane1.addTab(" "+item1+"  ",null,frm);28                 jTabbedPane1.addTab(" "+item1+"  ",this.tabIcon,frm);29 30              }31              catch (Throwable e) {32                 System.err.println(e);33              }34         } else {35             System.out.println("not leaf");36         }37     }       

 在javaswing中的路径也和net不同,下面定义了一个创建ImageIcon的方法:

 1     /** Returns an ImageIcon, or null if the path was invalid. */ 2     protected ImageIcon createImageIcon(String path,String description) { 3         java.net.URL imgURL = getClass().getResource(path); 4         if (imgURL != null) { 5             return new ImageIcon(imgURL, description); 6         } else { 7             System.err.println("Couldn't find file: " + path); 8             return null; 9         }10     }

 5 JDBC MYSQL代码

 1 package com.mkmis.db; 2  3 import java.io.FileInputStream; 4 import java.io.IOException; 5 import java.sql.Connection; 6 import java.sql.DriverManager; 7 import java.sql.PreparedStatement; 8 import java.sql.ResultSet; 9 import java.sql.SQLException;10 import java.sql.Statement;11 import java.util.Properties;12 13 14 public class DBConnection {15 16     public static Connection getConnection() {17         Properties props = new Properties();18         FileInputStream fis = null;19         Connection con = null;20         try {21             fis = new FileInputStream("db.properties");22             props.load(fis);23             //24             Class.forName(props.getProperty("DB_DRIVER_CLASS"));25             // 26             con = DriverManager.getConnection(props.getProperty("DB_URL"), props.getProperty("DB_USERNAME"), props.getProperty("DB_PASSWORD"));27         } catch (IOException | SQLException | ClassNotFoundException e) {28             e.printStackTrace();29         }30         return con;31     }32 33     // �ر�ResultSet34     public static void closeResultSet(ResultSet rs) {35         if (rs != null) {36             try {37                 rs.close();38                 rs = null;39             } catch (SQLException e) {40                 e.printStackTrace();41             }42         }43     }44 45     //Statement46     public static void closeStatement(Statement stm) {47         if (stm != null) {48             try {49                 stm.close();50                 stm = null;51             } catch (SQLException e) {52                 e.printStackTrace();53             }54         }55     }56 57     //PreparedStatement58     public static void closePreparedStatement(PreparedStatement pstm) {59         if (pstm != null) {60             try {61                 pstm.close();62                 pstm = null;63             } catch (SQLException e) {64                 e.printStackTrace();65             }66         }67     }68 69     //Connection70     public static void closeConnection(Connection con) {71         if (con != null) {72             try {73                 con.close();74                 con = null;75             } catch (SQLException e) {76                 e.printStackTrace();77             }78             con = null;79         }80     }81 82 }

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 6 图表窗体代码

  1 /*  2  * To change this license header, choose License Headers in Project Properties.  3  * To change this template file, choose Tools | Templates  4  * and open the template in the editor.  5  */  6 package com.mkmis.forms;  7   8 import java.awt.Color;  9 import java.awt.Dimension; 10 import java.awt.Font; 11  12 import org.jfree.chart.ChartFactory; 13 import org.jfree.chart.ChartPanel; 14 import org.jfree.chart.JFreeChart; 15 import org.jfree.chart.StandardChartTheme; 16 import org.jfree.chart.axis.CategoryAxis; 17 import org.jfree.chart.axis.NumberAxis; 18 import org.jfree.chart.block.BlockBorder; 19 import org.jfree.chart.plot.CategoryPlot; 20 import org.jfree.chart.renderer.category.BarRenderer; 21 import org.jfree.chart.title.TextTitle; 22 import org.jfree.data.category.CategoryDataset; 23 import org.jfree.data.category.DefaultCategoryDataset; 24 //import org.jfree.ui.ApplicationFrame; 25 //import org.jfree.ui.RefineryUtilities; 26 /** 27  * 28  * @author wangming 29  */ 30 public class JIFrame1 extends javax.swing.JInternalFrame { 31  32     /** 33      * Creates new form JIFrame1 34      */ 35     public JIFrame1() { 36         initComponents(); 37         //hiding title bar of JInternalFrame        38         ((javax.swing.plaf.basic.BasicInternalFrameUI)this.getUI()).setNorthPane(null); 39         this.setBackground(Color.white); 40          41         CategoryDataset dataset = createDataset(); 42         JFreeChart chart = createChart(dataset); 43         ChartPanel chartPanel = new ChartPanel(chart); 44         chartPanel.setFillZoomRectangle(true); 45         chartPanel.setMouseWheelEnabled(true); 46         chartPanel.setPreferredSize(new Dimension(500, 270)); 47         setContentPane(chartPanel); 48     } 49  50     /** 51      * This method is called from within the constructor to initialize the form. 52      * WARNING: Do NOT modify this code. The content of this method is always 53      * regenerated by the Form Editor. 54      */ 55     @SuppressWarnings("unchecked") 56     // <editor-fold defaultstate="collapsed" desc="Generated Code">                           57     private void initComponents() { 58  59         setBorder(null); 60         setClosable(true); 61         setMaximizable(true); 62         setResizable(true); 63  64         javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); 65         getContentPane().setLayout(layout); 66         layout.setHorizontalGroup( 67             layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 68             .addGap(0, 410, Short.MAX_VALUE) 69         ); 70         layout.setVerticalGroup( 71             layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 72             .addGap(0, 285, Short.MAX_VALUE) 73         ); 74  75         pack(); 76     }// </editor-fold>                         77  78         private static final long serialVersionUID = 1L; 79  80     static { 81         // set a theme using the new shadow generator feature available in 82         // 1.0.14 - for backwards compatibility it is not enabled by default 83         ChartFactory.setChartTheme(new StandardChartTheme("JFree/Shadow", 84                 true)); 85     } 86  87     /** 88      * Creates a new demo instance. 89      * 90      * @param title  the frame title. 91      */ 92     public JIFrame1(String title) { 93         super(title); 94         CategoryDataset dataset = createDataset(); 95         JFreeChart chart = createChart(dataset); 96         ChartPanel chartPanel = new ChartPanel(chart); 97         chartPanel.setFillZoomRectangle(true); 98         chartPanel.setMouseWheelEnabled(true); 99         chartPanel.setPreferredSize(new Dimension(500, 270));100         setContentPane(chartPanel);101     }102 103     /**104      * Returns a sample dataset.105      *106      * @return The dataset.107      */108     private static CategoryDataset createDataset() {109         DefaultCategoryDataset dataset = new DefaultCategoryDataset();110         dataset.addValue(7445, "JFreeSVG", "Warm-up");111         dataset.addValue(24448, "Batik", "Warm-up");112         dataset.addValue(4297, "JFreeSVG", "Test");113         dataset.addValue(21022, "Batik", "Test");114         return dataset;115     }116 117     /**118      * Creates a sample chart.119      *120      * @param dataset  the dataset.121      *122      * @return The chart.123      */124     private static JFreeChart createChart(CategoryDataset dataset) {125         //中文乱码,设置字体126         Font font=new Font("微软雅黑",Font.BOLD,18);//测试是可以的127       128       129        130        131         JFreeChart chart = ChartFactory.createBarChart("性能: JFreeSVG 对比 Batik", null /* x-axis label*/, 132                 "毫秒" /* y-axis label */, dataset);133         //中文乱码,设置字体134         chart.getTitle().setFont(font);135 136         chart.addSubtitle(new TextTitle("在SVG中产生1000个图表"));137         chart.setBackgroundPaint(Color.white);138         CategoryPlot plot = (CategoryPlot) chart.getPlot();139          NumberAxis rangeAxis = (NumberAxis) plot.getRangeAxis();140          rangeAxis.setLabelFont(font);141 142          CategoryAxis domainAxis = plot.getDomainAxis();143          domainAxis.setLabelFont(font);144         // ******************************************************************145         //  More than 150 demo applications are included with the JFreeChart146         //  Developer Guide...for more information, see:147         //148         //  >   http://www.object-refinery.com/jfreechart/guide.html149         //150         // ******************************************************************151 152       153         rangeAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());154         BarRenderer renderer = (BarRenderer) plot.getRenderer();155         renderer.setDrawBarOutline(false);156         chart.getLegend().setFrame(BlockBorder.NONE);157         return chart;158     }159 160     /**161      * Starting point for the demonstration application.162      *163      * @param args  ignored.164      */165 //    public static void main(String[] args) {166 //        BarChartDemo1 demo = new BarChartDemo1("JFreeChart: BarChartDemo1.java");167 //        demo.pack();168 //        RefineryUtilities.centerFrameOnScreen(demo);169 //        demo.setVisible(true);170 //    }171 172     // Variables declaration - do not modify                     173     // End of variables declaration                   174 }

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 运行此app,一定要引入需要的库,mysql jdbc驱动和jfreechart库