java笔记.doc

于亚洲java笔记1. Utill包中类用法2. I/O输入输出3. Swing界面4. Jkbc连接数据库5. Xml解析6. 反射(reflect)7. 网络编程8. 线程(Thread)9. MysqlUtill包中类用法/计算用时long t1 = System.currentTimeMillis();long t2 = System.currentTimeMillis();System.out.println(t2-t1); /格式化日期和时间SimpleDateFormat类用法import java.text.SimpleDateFormat;SimpleDateFormat sdf = new SimpleDateFormat(yyyy-mm-dd hh:mm:ss hs);/hs为毫秒System.out.print(sdf.format(new Date();/Date用法Date date = new Date();date.getTime();/返回自 1970 年 1 月 1 日 00:00:00 GMT 以来此 Date 对象表示的毫秒数为long类型date.toString();/把此 Date 对象转换为以下形式的 String： dow mon dd hh:mm:ss zzz yyyy 其中： dow 是一周中的某一天 (Sun, Mon, Tue, Wed, Thu, Fri, Sat)。/ Calendar用法Calendar calendar = Calendar.getInstance();int year = calendar.get(Calendar.YEAR); /得到年int month = calendar.get(Calendar.MONTH) + 1; /得到月int date = calendar.get(calendar.DATE); /得到日int hour = calendar.get(calendar.HOUR);/得到时int minute = calendar.get(calendar.MINUTE);/得到分int second = calendar.get(calendar.SECOND);/得到秒int week = calendar.get(calendar.DAY_OF_WEEK);/得到星期的第几天，周日为1，周一为2String a = year+-+month+-+date+ +hour+:+minute+:+second+ 星期+week; System.out.println(a);Date date = calendar.getTime(); /Random用法Random r = new Random();int a = r.nextInt();double d = r.nextDouble();/list和set和map用法（容器类用法） List可依对象被放置至容器中的顺序来排列对象 Set不接受重复的对象/ArrayList类中的常用方法List list = new ArrayList();list.add(a);/后面加入值list.add(b);list.add(0,22);/在第0个位置插入”22”System.out.print(list.indexOf(b);/结果为2，为b的索引位置System.out.print(list.contains(a);/是否包含alist.remove(0);/移除第0个元素/三种遍历方式for(int i = 0;ilist.size();i+)System.out.print(list.get(i);/得到值for(String l : list) /必须映射 System.out.print(l); Iterator iterator = list.iterator();while(iterator.hasNext() System.out.print(iterator.next();list.clear();/清空全部list.isEmpty();/判断是否为空list.firstElement();/第一个元素list.lastElement();/最后一个元素ArrayList和Vector区别在Vector是线程安全的/以上代码用LindedList运行和ArrayList运行结果一样，用法一样/以下为LinkedList中增加的代码，如果频繁增删，用LinkedList效率更高addFirst();addLast();getFirst();getLast();removeFirst();removeLast();/HashSet中常用方法/比较两个加入HashSet容器中的对象是否相同时，会先比较hashCode()方法。如果相同，则再使用equals()方法比较，如果两者都相同，则视为相同的对象/如果想要在迭代时按照加入的顺序显示，则可以使用LinkedHashSet，用法相似，只是迭代输出时按顺序Set set = new HashSet();set.add(a);set.add(b);set.add(a);System.out.print(set.size();/结果为2,因为添加的不能重复/遍历for(String s : set) System.out.print(s);Iterator iterator = set.iterator();while(iterator.hasNext() System.out.print(iterator.next();set.contains(a);set.isEmpty();set.remove(a);/里面放的是object类型，因为不会重复set.clear();/TreeSet以字典顺序存储对象，可以按顺序输出/以上代码用HashSet运行和TreeSet运行结果一样，用法一样/以下为TreeSet中增加的代码set.first();set.last();/HashMap的用法HashMap map = new HashMap();map.put(name,张三);map.put(ID,1001);System.out.println(map.get(name);System.out.println(map.get(ID);/迭代器遍历Collection collection = map.values();Iterator iterator = collection.iterator();while(iterator.hasNext() System.out.print(iterator.next();for(String s : map.keySet()/得到键的set System.out.print(s);I/O输入输出/File的用法File file = new File(info.txt);System.out.println(文件是否存在：+file.exists();System.out.println(是否是文件：+file.isFile();System.out.println(是否是文件夹：+file.isDirectory();System.out.println(文件名：+file.getName();System.out.println(文件路径：+file.getPath();System.out.println(绝对路径：+file.getAbsolutePath();Date date = new Date(file.lastModified();System.out.println(文件最后修改时间：+date.toLocaleString();System.out.println(文件大小:+file.length();File file = new File(info1.txt);if(!file.exists()file.createNewFile(); file.delete();File f= new File(aaa);f.mkdir();/创建文件夹/得到文件夹中的文件File f = new File(path);File files = f.listFile();/得到文件夹中的所有文件for(File file : files)/RandomAccessFile将文本显示到屏幕上File file = new File(“stu.txt”);RandomAccessFile raf = new RandomAccessFile(file,rw);raf.seek(5);/跳到第五行String line = ;while(line=raf.readLine()!=null)System.out.println(line);/FileInputStream用法File file = new File(d:abc.text);FileInputStream fis = new FileInputStream(file);FileOutputStream fos = new FileOutputStream(d:abc1.text);int i = -1;while(i = fis.read() != -1) fos.write(i);fis.close();fos.close();/BufferedInputStream用法File file = new File(d:abc.text);FileInputStream fis = new FileInputStream(file);FileOutputStream fos = new FileOutputStream(d:abc2.text);BufferedInputStream bis = new BufferedInputStream(fis);BufferedOutputStream bos = new BufferedOutputStream(fos);byte i = new byte1024;while(bis.read(i) != -1) bos.write(i);bos.flush(); /刷新缓冲区bos.close();fos.close();bis.close();fis.close();/FileReader用法FileReader fr = new FileReader(file);FileWriter fw = new FileWriter(d:abc3.text);int i = -1;char ln = r, n;while(i=fr.read() != -1)if(i = n) /写入rn fw.write(ln);else fw.write(i);fw.flush();/BufferedReader用法File file = new File(d:abc.text);FileReader fr = new FileReader(file);FileWriter fw = new FileWriter(d:abc3.text);BufferedReader br = new BufferedReader(fr);BufferedWriter bw = new BufferedWriter(fw);String line = ;while(line = br.readLine() != null) bw.write(line); bw.newLine();bw.flush();bw.close();br.close();fw.close();fr.close();/DataOutputStream的用法FileOutputStream fos = new FileOutputStream(new File(data.txt);DataOutputStream dos = new DataOutputStream(fos);Employee emp1 = new Employee(zsan,20);Employee emp2 = new Employee(lisi,30);Employee emps = new Employee2;emps0 = emp1;emps1 = emp2;for(int i=0;iemps.length;i+)dos.writeUTF(empsi.getName();dos.writeInt(empsi.getAge(); dos.close();fos.close();FileInputStream fis = new FileInputStream(new File(data.txt);DataInputStream dis = new DataInputStream(fis);for(int i=0;iscreenSize.width)frameSize.width=screenSize.height;if(frameSize.widthscreenSize.width)frameSize.width=screenSize.width;/JFrame居中frame.setLocation(screenSize.width-frameSize.widh)/2,(screenSize.height-frameSize.height)/2)/界面添加标题setTitle(记事本);/设置图标Toolkit tk=Toolkit.getDefaultToolkit() Image image=tk.createImage(image.gif); /image.gif是你的图标this.setIconImage(image);/可见frame.setVisible(true);/设置大小和位置.setBounds(0,0,1024,860);/定位点，大小.setsize(1024,860);/关闭界面jFrame1.setVisible(false);jFrame1.dispose();/单选和复选框等获得选中状态jRadioButton1.setSelected(true);jCheckBox1.setSelected(true);/为下拉菜单添加内容JComboBox jComboBox1 = new JComboBox();jComboBox1.addItem(邯郸);/下拉框选中事件则在Event事件中选择“itemStateChanged”。/得到下拉框中的值jComboBox1.getSelectedItem().toString(); /得到选中字符Integer.parseInt(“123456”); /字符转数字/选择文件界面File file;JFileChooser jfc = new JFileChooser(c:);int value = jfc.showOpenDialog(this);if(value=0)file = jfc.getSelectedFile(); int n = jfc.showSavaDialog();if(n=0)File file = jfc.getSelectedFile();/上下选择SpinnerNumberModel snm = new SpinnerNumberModel(3, 1, 12,2);/定义模型 范围是1到12，初始化为3,一次加2JSpinner monthSpin = new JSpinner()monthSpin.setModel(snm);monthSpin.setPreferredSize(new Dimension(35, 20);/设置大小monthSpin.setName(Month); /名字/弹出警告对话框JOptionPane.showMessageDialog(null,我被点中了);/弹出选择对话框 int i = JOptionPane.showConfirmDialog(null, 真的要删除吗,删除操作, JOptionPane.YES_NO_OPTION);if(i=0)/填选是要执行的代码/为label加图和文字Icon icon = newImageIcon(c:/a.jpg);this.label1.setIcon(icon);label1.setText(于亚洲);/list的使用String data = one, two, three, four;JList myList = new JList(data);/显示右键菜单1.添加此方法private static void addPopup(Component component, final JPopupMenu popup) component.addMouseListener(new MouseAdapter() public void mousePressed(MouseEvent e) if (e.isPopupTrigger() showMenu(e);public void mouseReleased(MouseEvent e) if (e.isPopupTrigger() showMenu(e);private void showMenu(MouseEvent e) popup.show(e.getComponent(), e.getX(), e.getY(););2.添加此组件JPopupMenu popupMenu = new JPopupMenu();addPopup(this, popupMenu);JMenu menu = new JMenu(查找);popupMenu.add(menu);3.添加单击事件textArea.addMouseListener(new MouseAdapter() Override public void mouseClicked(MouseEvent e) if(e.getButton()=e.BUTTON3) popupMenu.show(textArea, e.getX(), e.getY(); );/定义表格并加数据JTable jTable1 = new JTable();DefaultTableModel dtm = new DefaultTableModel (); /建模型dtm.addColumn(id); /添加标题dtm.addColumn(name);Vector vector = newVector(); /定义vectorvector.add(10016);vector.add(于亚洲);dtm.addRow(vector); /添加一行jTable1.setModel(dtm); /把模型加到表格中/清空表格中的全部数据for(int i=dtm.getRowCount()-1;i=0;i-)dtm.removeRow(i);/移除第i行/清空全部/得到选中的表格中的数据String col = jTable1.getModel().getValueAt(jTable1.getSelectedRow(),0).toString();int co=Integer.parseInt(col); /得选中行(jTable1.getSelectedRow()的第一个(0)数据/得到选中的行数和列数int I = jTable1.getSelectedColumn(); / getSelectedRow ()/设置表头最大宽度TableColumn tc=jTable1.getColumnModel().getColumn(0);tc.setMaxWidth(36);/最大宽度 tc.setPreferredWidth(2);/设宽度/表头不可移动jTable1.getTableHeader().setReorderingAllowed(false);/设置表格不可编辑见插件，让Dtm类代替DefaultTableModel;/设置表格调整方式 jTable1.setAutoResizeMode(JTable.AUTO_RESIZE_SUBSEQUENT_COLUMNS); 列可调整的 5 个参数： AUTO_RESIZE_SUBSEQUENT_COLUMENS:当调整某一列宽时，此字段之后的所有字段列 宽都会跟着一起变动。此为系统默认值。 AUTO_RESIZE_ALL_COLUMNS:当调整某一列宽时，此表格上所有字段的列宽都会跟着一 起变动。 AUTO_RESIZE_OFF:当调整某一列宽时，此表格上所有字段列宽都不会跟着改变。 AUTO_RESIZE_NEXT_COLUMN:当调整某一列宽时，此字段的下一个字段的列宽会跟着改 变，其余均不会变。 AUTO_RESIZE_LAST_COLUMN:当调整某一列宽时，最后一个字段的列宽会跟着改变，其 余均不会改变。 /更换paneJPanel panel = (JPanel)getContentPane(); /定义新panelpanel.setSize(contentPanel.getSize(); /contentPanel为原panelpanel.setVisible(true);contentPanel.removeAll();contentPanel.add(panel);contentPanel.repaint();/建立TreeJScrollPane js = new JScrollPane();JTree jtree1 = new JTree();DefaultMutableTreeNode root = new DefaultMutableTreeNode(于亚洲);DefaultMutableTreeNode childNode = new DefaultMutableTreeNode(zsan);root.add(childNode);jTree1 = new JTree(root);js.getViewport().add(jtree1);/选中事件DefaultMutableTreeNode node=(DefaultMutableTreeNode)this.jTree1.getLastSelectedPathComponent();node.isleaf();node.toString();Jdbc连接数据库/配置文件内容driver=com.mysql.jdbc.Driverurl=jdbc:mysql:/localhost:3306/mysql?useUnicode=true&characterEncoding=gb2312user=rootpsw=123456/读取配置文件Properties pro = new Properties();pro.load(new FileInputStream(perties);String url = pro.getProperty(url);String user = pro.getProterty(user);String psw = pro.getProperty(psw);/定义变量String driver=”com.mysql.jdbc.Driver”;String url=”jdbc:mysql:/localhost:3306/mysql?useUnicode=true&characterEncoding=gb2312”;String user=”root”;String psw=”123456”;/加载Class.forName(driver);/连接数据库Connection con=DriverManager.getConnection(url,user,psw);/分条执行String sql = insert into stu(id,name) values(10010,于亚洲);Statement sta = con.createStatement();int rows = sta.executeUpdate(sql); /返回受影响的行数if(rows0)System.out.println(执行成功);/ResultSet接收全部信息Statement sta = con.createStatement();ResultSet rs = sta.executeQuery(“select * from stu”);while(rs.next()int id = rs.getInt(id);/得到id值String name = rs.getString(name); /得到全部值ResultSetMetaData rsmd = rs.getMetaData();/ResultSetMetaData得到表头信息,表名、列名、字段型态System.out.println(表名t列名t列类型); for(int i=1;i=rsmd.getColumnCount();i+)System.out.println(rsmd.getTableName(i);System.out.println(rsmd.getColumnName(i);System.out.println(rsmd.getColumnTypeName(i);/批处理Statement sta = con.createStatement();sta.addBatch(insert into stu(id,name) values(10011,张三);sta.addBatch(insert into stu(id,name) values(10012,李四);int rows = sta.executeBatch();/预处理String sql = insert into stu(id,name) values(?,?);PreparedStatement pr=con.prepareStatement(sql);pr.setInt(1,10013);pr.setString(2,王五);int rows = pr.executeUpdate();/存二进制文件 在JDBC中也提供了java.sql.Blob与java.sql.Clob两个类别分别代表BLOB与CLOB资料File file = new File(./logo_phpbb.jpg);int length = (int) file.length();InputStream fin = new FileInputStream(file); /填入数据库PreparedStatement pstmt = conn.prepareStatement( INSERT INTO files VALUES(?, ?, ?);pstmt.setInt(1, 1);pstmt.setString(2, filename);pstmt.setBinaryStream (3, fin, length);pstmt.executeUpdate();pstmt.clearParameters();pstmt.close();fin.close();Blob blob = result.getBlob(2); /取得BLOBClob clob = result.getClob(2) /取得CLOBXml解析/SAX解析/需要导入jdom包FileInputStream fis = new FileInputStream(students.xml);SAXBuider saxb = new SAXBuider();/创建SAX解析器Document doc = sacb.build(his);/文档对象模型 需要导入org.jdom.DocumentElement root = doc.getRootElement();/获得根元素List lists = root.getRootElement();/获得根元素下子元素String name = root.getAttributeValue(name);/获取根节点的name属性/Dom解析导包时有org.w3c的导入它DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();/创建解析器工厂DocumentBuilder builder = factory.newDocumentBuilder();/创建文件解析器InputStream input =Main1.class.getResourceAsStream(students.xml);/ Main1为与XML文件在同一个包下的类Document doc = db.parse(input);或者用Document doc = builder.parse(student.xml);/获取文档对象/XML文件只能放在工程文件中NodeList nlist1 =doc.getChildNodes();/得到根节点Node node1 = nlist1.item(0);Element root = (Element)node1;/强转，Node是Element的父类NodeList nlist2 = root.getChildNodes();for(int i = 0;inlist2.getLength();i+)Node node =nlist2.item(i);if (node instanceof Element)Element element1 = (Element)node;Attr attr1 = element1.getAttributeNode(studentno);System.out.println(attr1.getNodeName()+attr1.getNodeValue();NodeList nodelist2 = element1.getChildNodes();for(int j=0;jnodelist2.getLength();j+)Node node2 = nodelist2.item(j);if(node2 instanceof Element)Element element2 = (Element)node2;Text text = (Text) element2.getFirstChild();System.out.println(text.getNodeValue();/用于获得局部值NodeList stus = doc.ge