API之Character类型_character常用api

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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