java.lang.*中Boolean 源代码详解

柔情只为你懂 2022-11-30 15:58 261阅读 0赞

### java.lang.\*中Boolean 源代码详解 ###

*   *  核心方法
     *  public Boolean(boolean value)
     *  boolean parseBoolean(String s)
     *  boolean booleanValue()
     *  Boolean valueOf()
     *  String toString()
     *  int hashCode()
     *  boolean equals(Object obj)
     *  boolean getBoolean(String name)
     *  compareTo(Boolean b)
     *  int compare(boolean x, boolean y)
     *  boolean logicalAnd(boolean a, boolean b)
     *  boolean logicalOr(boolean a, boolean b)
     *  boolean logicalXor(boolean a, boolean b)

## 核心方法 ##

public final class Boolean implements java.io.Serializable,Comparable<Boolean>
    
    public Boolean(boolean value) 构造方法[OK]
    boolean parseBoolean(String s) 将字符串转换成boolean值[OK]
    boolean booleanValue() 获取Boolean对象的boolean值[OK]
    Boolean valueOf() 获取boolean值对应的Boolean对象[OK]
    String toString() 获取Boolean值得toString形式[OK]
    int hashCode() 获取Boolean对象的hashCode值[OK]
    boolean equals(Object obj) 比较两个对象是否相等[OK]
    boolean getBoolean(String name) 当且仅当以参数命名的系统属性存在，且等于 "true" 字符串时，才返回 true[OK]
    int compareTo(Boolean b) 比较当前Boolean对象与b的值,如果相等返回0,否则返回1或者-1[OK]
    int compare(boolean x, boolean y) 比较x对象与y的值,如果相等返回0,否则返回1或者-1[OK]
    boolean logicalAnd(boolean a, boolean b) 获取a && b的值(逻辑并)[OK]
    boolean logicalOr(boolean a, boolean b) 获取a || b的值(逻辑或)[OK]
    boolean logicalXor(boolean a, boolean b) 获取a ^ b的值(逻辑异或)[OK]

## public Boolean(boolean value) ##

/** * Boolean的构造函数 * public static void main(String[] args) { Boolean b0 = new Boolean(null); Boolean b1 = new Boolean("ss"); Boolean b2 = new Boolean("false"); Boolean b3 = new Boolean("true"); Boolean b4 = new Boolean("trUe"); System.out.println(b0); System.out.println(b1); System.out.println(b2); System.out.println(b3); System.out.println(b4); } 执行效果： false false false true true */
    public Boolean(boolean value) { 
        this.value = value;
    }
    
    public Boolean(String s) { 
        this(parseBoolean(s));
    }

## boolean parseBoolean(String s) ##

/** * 将字符串转换成boolean值 */
    public static boolean parseBoolean(String s) { 
    	//只有当s不为null,并且 s.equalsIgnoreCase("true")时,返回true
        return ((s != null) && s.equalsIgnoreCase("true"));
    }

## boolean booleanValue() ##

/** * 获取Boolean对象的boolean值 */
    public boolean booleanValue() { 
        return value;
    }

## Boolean valueOf() ##

/** * 获取boolean值对应的Boolean对象 */
    public static Boolean valueOf(boolean b) { 
        return (b ? TRUE : FALSE);
    }
    
    public static Boolean valueOf(String s) { 
        return parseBoolean(s) ? TRUE : FALSE;
    }

## String toString() ##

/** * 获取boolean值得toString形式 */
    public static String toString(boolean b) { 
        return b ? "true" : "false";
    }

## int hashCode() ##

/** * 获取Boolean对象的hashCode值 * 1231 : true * 1237 : false */
    public int hashCode() { 
        return Boolean.hashCode(value);
    }
    
    public static int hashCode(boolean value) { 
        return value ? 1231 : 1237;
    }

## boolean equals(Object obj) ##

/** * 比较两个对象是否相等 */
    public boolean equals(Object obj) { 
    	//首先判断obj是否是Boolean类型
        if (obj instanceof Boolean) { 
        	//获取obj的booleanValue值,进行比较
            return value == ((Boolean)obj).booleanValue();
        }
        return false;
    }

## boolean getBoolean(String name) ##

/** * 当且仅当以参数命名的系统属性存在，且等于 "true" 字符串时，才返回 true */
    public static boolean getBoolean(String name) { 
        boolean result = false;
        try { 
            result = parseBoolean(System.getProperty(name));
        } catch (IllegalArgumentException | NullPointerException e) { 
        }
        return result;
    }

## compareTo(Boolean b) ##

public int compareTo(Boolean b) { 
        return compare(this.value, b.value);
    }

## int compare(boolean x, boolean y) ##

/** * 比较两个boolean对象是否相等,相等返回0,否则返回-1或者1 */
    public static int compare(boolean x, boolean y) { 
        return (x == y) ? 0 : (x ? 1 : -1);
    }

## boolean logicalAnd(boolean a, boolean b) ##

/** * 获取a && b的值(逻辑并) */
    public static boolean logicalAnd(boolean a, boolean b) { 
        return a && b;
    }

## boolean logicalOr(boolean a, boolean b) ##

/** * 获取逻辑a || b的值 */
    public static boolean logicalOr(boolean a, boolean b) { 
        return a || b;
    }

## boolean logicalXor(boolean a, boolean b) ##

/** * 获取逻辑异或的值 * a == b 返回 false * a != b 返回 true */
    public static boolean logicalXor(boolean a, boolean b) { 
        return a ^ b;
    }

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