common-lang類的學習（二）

接上一篇

 

五、對象工具類：

/* * 對象工具類 */ public void objectUtilsDemo() { System.out.println("**ObjectUtilsDemo**"); System.out.println("Object爲null時，默認打印某字符."); Object obj = null; System.out.println(ObjectUtils.defaultIfNull(obj, "空")); System.out.println("驗證兩個引用是否指向的Object是否相等,取決於Object的equals()方法."); Object a = new Object(); Object b = a; Object c = new Object(); System.out.println(ObjectUtils.equals(a, b)); System.out.println(ObjectUtils.equals(a, c)); System.out.println("用父類Object的toString()方法返回對象信息."); Date date = new Date(); System.out.println(ObjectUtils.identityToString(date)); System.out.println(date); System.out.println("返回類本身的toString()方法結果,對象爲null時，返回0長度字符串."); System.out.println(ObjectUtils.toString(date)); System.out.println(ObjectUtils.toString(null)); System.out.println(date); } 

 

六、序列化工具類：

/* * 序列化工具類 */ public void serializationUtilsDemo() { System.out.println("*SerializationUtils**"); Date date = new Date(); //序列化成一個字節數組 byte[] bytes = SerializationUtils.serialize(date); System.out.println(ArrayUtils.toString(bytes)); System.out.println(date); //反序列化成對象 Date reDate = (Date) SerializationUtils.deserialize(bytes); System.out.println(reDate); //值相等 System.out.println(ObjectUtils.equals(date, reDate)); //但不是同一個對象 System.out.println(date == reDate); FileOutputStream fos = null; FileInputStream fis = null; try { fos = new FileOutputStream(new File("d:/test.txt")); fis = new FileInputStream(new File("d:/test.txt")); //將對象序列化後寫到文件中 SerializationUtils.serialize(date, fos); //從文件中讀出對象 Date reDate2 = (Date) SerializationUtils.deserialize(fis); System.out.println(date.equals(reDate2)); } catch (FileNotFoundException e) { e.printStackTrace(); } finally { try { fos.close(); fis.close(); } catch (IOException e) { e.printStackTrace(); } } } 

 

七、隨機字符串類

/* * 隨機字符串類 */ public void randomStringUtilsDemo() { System.out.println("**RandomStringUtilsDemo**"); System.out.println("生成指定長度的隨機字符串"); System.out.println(RandomStringUtils.random(500)); System.out.println("在指定字符串中生成長度爲n的隨機字符串."); System.out.println(RandomStringUtils.random(5, "abcdefghijk")); System.out.println("指定從字符或數字中生成隨機字符串(驗證碼可以用)."); System.out.println(RandomStringUtils.random(5, true, false)); System.out.println(RandomStringUtils.random(5, false, true)); System.out.println(RandomStringUtils.random(5, true, true)); } 

 

八、類工具類

/* * 類工具類 */ public void classUtilsDemo() { System.out.println(genHeader("ClassUtilsDemo")); System.out.println("獲取類實現的所有接口."); System.out.println(ClassUtils.getAllInterfaces(Date.class)); System.out.println("獲取類所有父類."); System.out.println(ClassUtils.getAllSuperclasses(Date.class)); System.out.println("獲取簡單類名."); System.out.println(ClassUtils.getShortClassName(Date.class)); System.out.println("獲取包名."); System.out.println(ClassUtils.getPackageName(Date.class)); System.out.println("判斷是否可以轉型."); System.out.println(ClassUtils.isAssignable(Date.class, Object.class)); System.out.println(ClassUtils.isAssignable(Object.class, Date.class)); } 

 

九、數值工具

/* * 數值工具 */ public void numberUtils() { System.out.println(genHeader("NumberUtils")); System.out.println("字符串轉爲數字，不能轉的爲0"); System.out.println(NumberUtils.toInt("35")); System.out.println("從數組中選出最大值."); System.out.println(NumberUtils.max(new int[] { 1, 2, 3, 4 })); System.out.println("判斷字符串是否全是整數."); System.out.println(NumberUtils.isDigits("123.1")); System.out.println("判斷字符串是否是有效數字."); System.out.println(NumberUtils.isNumber("0123.1")); }