java.lang.Boolean

  1 /*
  2  * public final class Boolean extends Object implements Serializable,Comparable<Boolean>
  3  * Boolean类的对象中包装基本类型boolean的值。
  4  */
  5 public class BooleanDmeo {
  6 
  7     public static void main(String[] args) {
  8         logicalAndDemo();
  9     }
 10 
 11     public static void fieldDemo() {
 12         // Boolean字段
 13         // public static final Boolean TRUE
 14         // public static final Boolean FALSE
 15         // public static final 类<Booolean> TYPE
 16         System.out.println(Boolean.FALSE);
 17         System.out.println(Boolean.TRUE);
 18         System.out.println(Boolean.TYPE);
 19 
 20     }
 21 
 22     public static void parseBooleanDemo() {
 23         // public static boolean parseBoolean(String s)
 24         // 将字符串解析为布尔值，
 25         // 当字符串不为null且等于（忽略大小写）“true”时，返回true
 26         // 其余情况返回false
 27         System.out.println(Boolean.parseBoolean(null));
 28         System.out.println(Boolean.parseBoolean("true"));
 29         System.out.println(Boolean.parseBoolean("false"));
 30         System.out.println(Boolean.parseBoolean("aaa"));
 31     }
 32 
 33     public static void booleanValueDemo() {
 34         // public boolean booleanValue()
 35         // 以Boolean元的形式返回此Boolean对象的值
 36         Boolean b1 = true;
 37         Boolean b2 = false;
 38         System.out.println(b1.booleanValue());
 39         System.out.println(b2.booleanValue());
 40     }
 41 
 42     public static void valueOfDemo() {
 43         // public static Boolean valueOf(boolean b)
 44         // 返回表示指定boolean值的Boolean实例。
 45         // 如果不需要新的Boolean实例，则通常应优先使用此方法，而不是构造函数
 46         // 此方法可能会产生明显更好的空间和时间性能
 47         Boolean b1 = true;
 48         Boolean b2 = false;
 49         System.out.println(Boolean.valueOf(b1));
 50         System.out.println(Boolean.valueOf(true));
 51         System.out.println("-----------");
 52         // public static Boolean valueOf(String s)
 53         System.out.println(Boolean.valueOf("true"));
 54     }
 55 
 56     public static void toStringDemo() {
 57         // public static String toString(boolean b)
 58         // 返回指定boolean的String对象
 59         System.out.println(Boolean.toString(true).getClass());
 60         System.out.println("-----------");
 61         Boolean b = false;
 62         System.out.println(b.toString());
 63     }
 64 
 65     public static void hashCodeDemo() {
 66         Boolean b1 = true;
 67         Boolean b2 = false;
 68         System.out.println(b1.hashCode());
 69         System.out.println(b2.hashCode());
 70         System.out.println("-----------");
 71         System.out.println(Boolean.hashCode(b1));
 72         System.out.println(Boolean.hashCode(b2));
 73     }
 74 
 75     public static void equalsDemo() {
 76         // public boolean equals(Object obj)
 77         Object o = true;
 78         Boolean b = false;
 79         System.out.println(b.equals(o));
 80     }
 81 
 82     public static void getBooleanDemo() {
 83         // public static boolean getBoolean(String name)
 84         // 当系统属性中，存在值等于true时，返回true
 85         // 否则返回false
 86         // name--键
 87         String key = "key";
 88         String value = "true";
 89         System.setProperty(key, value);
 90         System.out.println(Boolean.getBoolean(key));
 91     }
 92 
 93     public static void compareToDemo() {
 94         // public int compareTo(Boolean b)
 95         // 0--此对象表示与参数相同的布尔值
 96         // 1--此对象为true，参数为false
 97         // -1--此对象为false，参数为true
 98         Boolean b1 = true;
 99         Boolean b2 = true;
100         Boolean b3 = false;
101         System.out.println(b1.compareTo(b2));
102         System.out.println(b1.compareTo(b3));
103         System.out.println(b3.compareTo(b1));
104     }
105 
106     public static void compareDemo() {
107         // public static int compare(boolean x,boolean y)
108         // 1--x为true，y为false
109         // -1--x为false，y为true
110         // 0--x与y布尔值相同
111         Boolean b1 = true;
112         Boolean b2 = true;
113         Boolean b3 = false;
114         System.out.println(Boolean.compare(b1, b3));
115         System.out.println(Boolean.compare(b3, b1));
116         System.out.println(Boolean.compare(b1, b1));
117         System.out.println(Boolean.compare(b3, b3));
118     }
119 
120     public static void logicalAndDemo() {
121         // public static boolean logicalAnd(boolean a,boolean b)
122         Boolean b1 = true;
123         Boolean b2 = true;
124         Boolean b3 = false;
125         System.out.println(Boolean.logicalAnd(b1, b2));// 逻辑与
126         System.out.println(Boolean.logicalOr(b1, b2));// 逻辑或
127         System.out.println(Boolean.logicalXor(b1, b2));// 逻辑异或
128 
129     }
130 }