Java学习工具类

整理如下工具类

import java.awt.Color;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.ObjectInputStream;import java.io.ObjectOutputStream;import java.io.OutputStream;import java.util.HashMap;/** * 工具类 * @author legendary * */public final class MyUtil {    private MyUtil(){        throw new AssertionError();    }    /**     * 读取文件     * @return 键值Map     */    public static HashMap<String, Object> readFile(){        System.out.println("读成功");        ObjectInputStream in = null;        HashMap<String, Object> all = null;        try {            in = new ObjectInputStream(new FileInputStream("file.data"));            all = (HashMap<String, Object>) in.readObject();        } catch (FileNotFoundException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (ClassNotFoundException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }finally{            if (in != null) {                try {                    in.close();                } catch (IOException e) {                    // TODO Auto-generated catch block                    e.printStackTrace();                }            }        }        return all;    }    /**     * 写文件     * @param map 写出键值对     * @throws ClassNotFoundException 可能存在异常     */    public static void writeFile(HashMap<String, Object> map) throws ClassNotFoundException{        ObjectOutputStream out = null;        try {            out = new ObjectOutputStream(new FileOutputStream("file.data"));            out.writeObject(map);        } catch (FileNotFoundException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } finally{            if (out != null) {                try {                    out.close();                } catch (IOException e) {                    // TODO Auto-generated catch block                    e.printStackTrace();                }            }        }    }    /**     * 短除法求最大公约数     * @param x 输入的整数 x     * @param y 输入的整数 y     * @return 最大公约数     */    public static int gcd(int x, int y){        if (x > y) {            return gcd(y,x);        }        else if (y % x != 0) {            return gcd(y % x , x);        }        else {            return x;        }    }    /**     * 求整数 min和 max范围内的一个随机整数     * @param min 最小范围     * @param max 最大范围     * @return 随机值     */    public static int random(int min ,int max){        return (int) (Math.random()*(max - min +1) + min);    }    /**     * 产生一个随机颜色     * @return 颜色     */    public static Color color(){        int red = (int) (Math.random()*MyUtil.random(0, 250));        int green = (int) (Math.random()*MyUtil.random(0, 250));        int blue = (int) (Math.random()*MyUtil.random(0, 250));        return new Color(red, green, blue);    }    /**     * 计算阶乘 n ！ = n * (n-1) * (n - 2)……*2 *1     * @param n     * @return       * @throws Exception     */    public static double factorial(int n) throws TooSmallException,TooBigException{        if (n < 0 ) {            throw new TooSmallException("参数值不能小于0");        }else if (n >170) {            throw new TooBigException("参数值不能大于170");        }        double defult = 1;        for (int i = 1; i < n; i++) {            defult *= i;        }        return defult;    }    /**     * 拷贝文件     * @param sourceFile 源文件地址及名字     * @param targetFile 目标地址及名字     * @throws IOException 输入输出异常     */    public static void fileCopy(String sourceFile, String targetFile) throws IOException{        InputStream in  = null;        OutputStream out = null;        try {            in = new FileInputStream(sourceFile);            int indexofSlash = targetFile.lastIndexOf("/");            if (indexofSlash > 1) {                File f = new File(targetFile.substring(0, indexofSlash));                if (!f.exists()) {                    f.mkdirs();                }            }            out = new FileOutputStream(targetFile);            byte[] buffer = new byte[1024];            int b = in.read(buffer);            while (b != -1) { //文件结束符号                out.write(buffer, 0, b);                b = in.read(buffer);            }        } catch (IOException e) {            throw e;        } finally{            if (in != null) {                in.close();            }            if (out != null) {                out.close();            }        }    }    /**     * 声明两个新的异常     * @author legendary     * 太小、太大     */    private static class TooSmallException extends Exception{        public TooSmallException(String msg){            super(msg);        }    }    private static class TooBigException extends Exception{        public TooBigException(String msg){            super(msg);        }    }}

     /**     * 二分查找法     * @param array 有序的数组     * @param key 待找的元素     * @return  找到就返回数组下标，没有就返回-1     */    public static <T extends Comparable<T>> int binarySearch(T[] array, T key){        int min = 0;        int max = array.length -1;        while (min <=max) {            int mid = (min + max) >>> 1;            if (array[mid].compareTo(key) > 0) {                max = mid - 1;            } else if (array[mid].compareTo(key) < 0) {                min = mid + 1;            } else {                return mid;            }        }        return -1;    }    /**     * 鸡尾酒排序     * @param array 等待排序的数组     */    public static <T extends Comparable<T>> void sort(T[] array){        boolean swapped = true;        for (int i = 1;swapped && i <= array.length -1;) {            swapped = false;            switch (i%2) {            case 0:                for (int j = 0; j < array.length - i; j++) {                    if (array[j].compareTo(array[j + 1]) > 0) {                        T temp = array[j];                        array[j] = array[j + 1];                        array[j + 1] = temp;                        swapped = true;                    }                }                break;            case 1:                for (int j = array.length -1; j >= i; j--) {                    if (array[j-1].compareTo(array[j]) > 0) {                        T temp = array[j - 1];                        array[j-1] = array[j];                        array[j] = temp;                        swapped = true;                        i++;                    }                }                break;            }        }    }    /**     * 冒泡排序     * @param array 暂时无法排序的数组     * @param comp 定义零时排序规则     */    public static <T> void sort(T[] array,Comparator<T> comp){        boolean swapped = true;        for (int i = 1;swapped && i <= array.length -1; i++) {            swapped = false;            for (int j = 0; j < array.length - i; j++) {                if (comp.compare(array[j],array[j+1]) > 0) {                    T temp = array[j];                    array[j] = array[j+1];                    array[j+1] = temp;                    swapped = true;                }            }        }    }