ade layout erl har 從0到1 rec cas 時間 implement

//輸入輸出Scanner in = new Scanner(System.in);int a = in.nextInt();int b = in.next();System.out.println(in.nextLine());
//輸入流 InputStreamSystem.in.read(buffer); //讀取輸入流存到buffer（byte[]類型）中System.in.read(); //讀一個字節，若結尾返回-1System.in.read(buffer, int off, int len); // 讀len個字節，從buffer[off]開始存System.in.skip(n); //輸入流跳過n個字節System.in.available();System.in.mark(); //標記System.in.reset(); //返回標記處System.in.markSupported; //是否支持標記System.in.close(); //關閉輸入流
//類java.io.StreamTokenizer可以獲取輸入流並將其分析為Token(標記)。StreamTokenizer的nextToken方法將讀取下一個標記,下一個標記的類型在ttype字段中返回。關於令牌的附加信息可能是在nval字段或標記生成器的sval 字段，結束標誌為TT_EOF。
StreamTokenizer st = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
st.nextToken();int m=(int)st.nval;
//輸出流 OutputStreamSystem.out.write(int b);System.out.write(byte[] b);System.out.write(byte[] b, int off, int len);System.out.flush();System.out.close();
//文件流//二進制數據讀寫（字節流）FileOutputStream out = new FileOutputStream("a.txt"); //根據字節讀寫數據out.write(buffer);out.close(); FileInputStream in = new FileInputStream("a.txt");in.read();in.close();DataOutputStream out = new DataOutputStream( new BufferedOutputStream( new FileOutputStream("a.txt"))); //讀寫基本類型數據out.writeInt(int a);DataInputStream in = new DataInputStream( new BufferedInputStream( new FileInputStream("a.txt")));
in.readInt();//文本數據讀寫（字符流）PrintWriter out = new PrintWriter( new BufferedWriter( new OutputStreamWriter( new FileOutputStream("a.txt")))); //輸出文本數據out.println("abcdefg");out.format("格式",...);out.printf("格式", ...);out.print(基本類型);
BufferedReader in = new BufferedReader( new InputStreamReader( new FileInputStream("a.txt"))); //讀文本數據
String line = in.readLine();in.getLineNumber();FileReader in = new FileReader(String fileName); //在給定從中讀取數據的文件名的情況下新建FileReaderFileReader in = new FileReader(File file); //在給定從中讀取數據的File的情況下新建FileReader//轉換編碼InputStreamReader(InputStream in, String charsetName); //創建使用指定字符集的InputStreamReader //網絡端口連接讀寫數據Socket socket = new Socket(InetAddress.getByName("localhost"), 12345); //建立與本地12345端口的連接PrintWriter out = new PrintWriter( new BufferedWriter( new OutputStreamWriter( socket.getOutputStream()))); //建立對socket的輸出流//讀寫對象class Student implements Serializable {...} //類實現Serializable串行化接口ObjectOutputStream out = new ObjectOutputStream( new FileOutputStream("a.dat")); //對象輸出流out.writeObject(Student stu1);ObjectInputStream in = new ObjectInputStream( new FileInputStream("a.dat"); //對象輸入流out.readObject(Student stu2); //字符串操作String s = new String();s.equals("abc");s1.compareTo(s2);s.substring(n);s.substring(n1, n2);s.charAt(index);s.indexOf(c);s.indexOf(c, n);s.indexOf(t); //也可以尋找字符串位置s.lastIndexOf(c); //從右邊開始找s.startsWith(t); //是否由字符串t開始s.endsWith(t); //是否由字符串t結尾s.trim(); //把字符串兩端的空格刪掉s.replace(c1, c2); //把s中所有的c1都換成c2s.toLowerCase(); //把s中所有的大寫字母換成小寫字母s.toUpperCase(); //把s中所有的小寫字母換成大寫字母s.split(" "); //按某個字符（比如空格）將字符串提取出來StringBuffer sb = new StringBuffer(); //用作字符串緩存器StringBuilder sb = new StringBuilder(); //與StringBuffer相似，沒有實現線程安全功能sb.append(""); //增加一個字符串sb.insert(n, ""); //插入字符串sb.toString(); //轉換成字符串String.format("Hello, %s. Next year, you‘ll be %d", name, age); //格式化字符串
//Java中的包裝類Integer類的常用方法：byteValue() //將Integer轉換為byte類型doubleValue() //將Integer轉換為double類型...基本類型轉換為字符串：Integer.toString(int n) //轉換為字符串類型
String.valueOf(int n) //int類型轉換為字符串類型
字符串轉換為基本類型：Integer.parseInt(Stirng s) //將字符串轉換為int類型Integer.valueOf(String s) //將字符串轉換為Integer類型
//時間類Date d = new Date(); //java.util包中，默認無參構建當前時間SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); //java.text包中，創建目標格式對象String today = sdf.format(d); //將時間格式化為指定格式Date date = sdf.parse(today); //將字符串按指定格式轉化為時間-------Calendar c = Calendar.getInstance(); //java.util.Calendar，創建Calendar對象，初始化為當前時間int year = c.get(Calendar.YEAR);int month = c.get(Calendar.MONTH)+1; //0表示1月份int day = c.get(Calendar.DAY_OF_MONTH);int hour = c.get(Calendar.HOUR_OF_DAY);int minute = c.get(Calendar.MINUTE);int second = c.get(Calendar.SECOND);Date date = c.getTime(); //Date和Calendar類互轉Long time = c.getTimeInMillis(); //獲取當前毫秒數
//數學函數Math.abs(a); // java.lang包，求絕對值Math.pow(a); //指數運算Math.random(); //產生從0到1間的隨機數Math.round(a); //求近似Math.floor(); //返回小於參數的最大整數Math.ceil(); //返回大於參數的最小整數
//集合//容器類
Collection接口，子接口有Set，List，Queue，實現類有ArrayList, LinkedList, HashSetMap接口，實現類有HashMap---------ArrayList<String> list = new ArrayList<String>(); //定義ArrayList容器，ArrayList是List接口的一個實現類，List是Collection的子接口list.add(s); //增加元素list.add(n, s); //在位置n上插入元素list.addAll(Array.asList(array)); //將數組轉換為list並添加到list中list.addAll(n, Array.asList(array)); //插入到指定位置list.remove(s); //刪除指定元素或指定位置元素list.removeAll(Array.asList(array)); //刪除list中指定的元素集合list.set(n, s); //修改n位置的元素為slist.size(); //返回大小Iterator it = list.iterator(); //獲取list的叠代器it.hasNext(); //判斷叠代器是否有下一個元素it.Next(); //利用叠代器獲取下一個元素
//HashMap散列表HashMap<Integer, String> coinnames = new HashMap<Integer, String>();coinnames.put(1, "penny"); //放進鍵值對coinnames.get(1); //返回鍵1對應的值coinnames.containsKey(1); //是否包含某鍵coinnames.keySet(); //返回鍵的集合
//圖形界面包import javax.swing.JFrame; //圖形窗口import javax.swing.JPanel; //圖形面板import javax.swing.JButton; //圖形按鈕
import java.awt.Color; //顏色設置import java.awt.Graphics; //繪制圖像import java.awt.BorderLayout; //組件布局管理import java.awt.event.ActionEvent; //事件處理import java.awt.event.ActionListener; //事件監聽import javax.swing.JScrollPane; //滾動面板import javax.swing.JTable; //圖形表格import javax.swing.table.TableModel; //表格的數據模型接口

//圖片格式轉換、改變大小

package com.qyluo.tmall.utils;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.*;
import java.io.File;
import java.io.IOException;
/**
 * Created by qy_lu on 2017/5/10.
 */
public class ImageUtil {
    public static BufferedImage change2jpg(File f) {
        try {
            java.awt.Image i = Toolkit.getDefaultToolkit().createImage(f.getAbsolutePath());
            PixelGrabber pg = new PixelGrabber(i, 0, 0, -1, -1, true);
            pg.grabPixels();
            int width = pg.getWidth(), height = pg.getHeight();
            final int[] RGB_MASKS = { 0xFF0000, 0xFF00, 0xFF };
            final ColorModel RGB_OPAQUE = new DirectColorModel(32, RGB_MASKS[0], RGB_MASKS[1], RGB_MASKS[2]);
            DataBuffer buffer = new DataBufferInt((int[]) pg.getPixels(), pg.getWidth() * pg.getHeight());
            WritableRaster raster = Raster.createPackedRaster(buffer, width, height, width, RGB_MASKS, null);
            BufferedImage img = new BufferedImage(RGB_OPAQUE, raster, false, null);
            return img;
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return null;
        }
    }
    public static void resizeImage(File srcFile, int width,int height, File destFile) {
        try {
            Image i = ImageIO.read(srcFile);
            i = resizeImage(i, width, height);
            ImageIO.write((RenderedImage) i, "jpg", destFile);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    public static Image resizeImage(Image srcImage, int width, int height) {
        try {
            BufferedImage buffImg = null;
            buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            buffImg.getGraphics().drawImage(srcImage.getScaledInstance(width, height, Image.SCALE_SMOOTH), 0, 0, null);
            return buffImg;
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }
}

//上傳文件解析相關包

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

   public InputStream parseUpload(HttpServletRequest request, Map<String, String> params) {
        InputStream is = null;
        try {
            DiskFileItemFactory factory = new DiskFileItemFactory();
            ServletFileUpload upload = new ServletFileUpload(factory);
            factory.setSizeThreshold(1024 * 10240);
            List items = upload.parseRequest(request);
            Iterator iterator = items.iterator();
            while (iterator.hasNext()) {
                FileItem item = (FileItem) iterator.next();
                if (!item.isFormField()) {
                    is = item.getInputStream();
                } else {
                    String paramName = item.getFieldName();
                    String paramValue = item.getString();
                    paramValue = new String(paramValue.getBytes("ISO-8859-1"), "UTF-8");
                    params.put(paramName, paramValue);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return is;
    }

學習筆記--Java