Java.lang Boolean

1 Java.lang Boolean介绍

Java.lang Boolean布尔类将原始类型boolean的值包装在对象中。其对象仅包含一个类型为布尔值的字段。

2 Java.lang Boolean声明

public final class Boolean
   extends Object
      implements Serializable, Comparable<Boolean>

3 Java.lang Boolean方法

4 Java.lang Boolean案例1

package com.yiidian;

/**
 * 一点教程网： http://www.yiidian.com
 */
public class JavaBooleanExample1 {  
    public static void main(String[] args) {  
        Boolean b1= true;  
        boolean b2=false;  
        //assigning boolean value of b1 to b3  
        Boolean b3= b1.booleanValue();  
        String str1 = "Value of boolean object "+b1+" is "+b3+".";  
        System.out.println(str1);  
        //compare b1 and b2  
            int val1 = Boolean.compare(b1,b2);  
        if(val1>0){  
            System.out.println("b1 is true.");  
            }  
            else{  
            System.out.println("b2 is true");  
        }  
        // logicalAnd() with return the same result as AND operator  
        Boolean val2 = Boolean.logicalAnd(b1,b2);  
        System.out.println("Logical And will return "+val2);  
    }  
}  

输出结果为：

Value of boolean object true is true.
b1 is true.
Logical And will return false

5 Java.lang Boolean案例2

package com.yiidian;

/**
 * 一点教程网： http://www.yiidian.com
 */
public class JavaBooleanExample2 {  
    public static void main(String[] args) {  
        Boolean b1 = true;  
        System.out.println("Boolean value = " + b1);  
        //prints the hash code of the boolean value  
        System.out.println("Hash Code for boolean value = " + b1.hashCode());  
        //converting boolean value tp String  
        String str = b1.toString();  
        System.out.println("String value = " + str);  
        System.out.println("Hash Code for String Value = " + str.hashCode());  
        // will return a boolean instance corresponding to Boolean b1  
        Boolean b2 = Boolean.valueOf(b1);  
        System.out.println("valueOf() method will return = " + b2);  
        boolean val1 = false;  
        for (int i = 0; i < 10; i++) {  
            if (i == 5) {  
                System.setProperty("val1", "true");  
                break;  
            }  
        }  
            boolean b3 = Boolean.getBoolean("val1");  
            System.out.println("value of val is " + b3);  
    }  
}  

输出结果为：

Boolean value = true
Hash Code for boolean value = 1231
String value = true
Hash Code for String Value = 3569038
valueOf() method will return = true
value of val is true