API之Character类型

旧城等待， 2022-06-12 05:23 214阅读 0赞

package com.wonders.week01;
    
    /**
     * 以JDK1.7为基础
     * java.lang.Character类
     * (1)是final修饰的类
     * (2)实现了接口java.io.Serializable, Comparable<Character>
     * (3)该类具有内部类:public static class Subset
     * (a)成员变量private String name
     * (b)方法:
     * protected Subset(String name) 如果name为null,会抛出NullPointException
     * public final boolean equals(Object obj)
     * public final int hashCode()
     * public final String toString()
     * 内部类:public static final class UnicodeBlock extends Subset
     * 内部类:private static class CharacterCache
     * (4)构造方法:
     * public Character(char value)
     * @author liyongyong
     *
     */
    public class CharacterTest {
    
    	static Character character = (Character)'a';
    	public static void main(String[] args) {
    		
    		System.out.println(Character.MIN_RADIX);//2
    		System.out.println(Character.MAX_RADIX);//36
    		System.out.println(Character.MIN_VALUE);//'\u0000'
    		System.out.println(Character.MAX_VALUE);//'\uFFFF'
    		
    		/*
    		 * public static Character valueOf(char c)
    		 * (1)静态方法,返回值类型Character对象
    		 * (2)参数类型是char,字符型
    		 */
    		Character c1 = Character.valueOf('1');
    		System.out.println(c1);//1
    		Character c2 = Character.valueOf('@');
    		System.out.println(c2);//@
    		
    		/*
    		 * public char charValue()
    		 * (1)非静态方法,返回值类型char,无参数
    		 * (2)如果Character对象为null,调用charValue方法会报NullPointException异常
    		 */
    		char ch1 = character.charValue();
    		System.out.println(ch1);//a
    		
    		/*
    		 * public int hashCode()
    		 * (1)非静态方法,无参数,返回值类型是int类型
    		 * (2)返回值是将值强制类型转为int型返回
    		 */
    		int chHashCode = character.hashCode();
    		System.out.println(chHashCode);//字符a的哈希值是97
    		
    		/*
    		 * public boolean equals(Object obj)
    		 * (1)非静态方法,返回值类型是boolean型,参数是一个对象
    		 * (2)如果该对象是Character的对象,将对象强转为Character型并且调用charValue()方法
    		 * 根据判断结果返回true或者false
    		 * (3)如果对象不是Character的对象,直接返回false
    		 */
    		boolean flag = character.equals((Character)'a');
    		System.out.println(flag);//true
    		boolean flag1 = character.equals((Character)'b');
    		System.out.println(flag1);//false
    		boolean flag2 = character.equals(3);
    		System.out.println(flag2);//false
    		
    		/*
    		 * public String toString()
    		 * (1)非静态方法,无参数,返回值类型是String类型
    		 * (2)调用了String.valueOf()方法
    		 */
    		String str1 = character.toString();
    		System.out.println(str1);//a
    		
    		/*
    		 * public static String toString(char c)
    		 * (1)静态方法,返回值类型是String类型,参数是一个字符型char
    		 * (2)调用了String.valueOf(char c)方法
    		 */
    		String str2 = Character.toString('$');
    		System.out.println(str2);//$
    		
    		/*
    		 * public static boolean isLowerCase(char ch)
    		 * (1)静态方法,返回值类型是布尔型,参数是一个字符char
    		 */
    		boolean flag3 = Character.isLowerCase('A');
    		System.out.println(flag3);//false
    		
    		/*
    		 * public static boolean isLowerCase(int codePoint)
    		 * (1)静态方法,返回值类型是boolean,参数是一个int型
    		 */
    		boolean flag4 = Character.isLowerCase(2);
    		System.out.println(flag4);//false
    		
    		/*
    		 * public static boolean isUpperCase(char ch)
    		 * (1)静态方法,返回值类型是布尔型,参数是一个字符char
    		 */
    		boolean flag5 = Character.isUpperCase('A');
    		System.out.println(flag5);//true
    		
    		/*
    		 * public static boolean isUpperCase(int codePoint)
    		 * (1)静态方法,返回值类型是boolean,参数是一个int型
    		 */
    		boolean flag6 = Character.isUpperCase(2);
    		System.out.println(flag6);//false
    		
    		/*
    		 * public static boolean isDigit(char ch)
    		 * (1)静态方法,返回值类型是布尔型,参数是一个字符char
    		 */
    		boolean flag7 = Character.isDigit('2');
    		System.out.println(flag7);//true
    		
    		/*
    		 * public static boolean isDigit(int codePoint)
    		 * (1)静态方法,返回值类型是boolean,参数是一个int型
    		 */
    		boolean flag8 = Character.isDigit(2);
    		System.out.println(flag8);//false
    		
    	}
    
    }

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