Java Boolean getBoolean()方法

java.lang.Boolean.getBoolean(String name) 当且仅当存在以参数命名的系统属性和等于该字符串“true”，则返回true。系统属性通过getProperty方法，通过System类中定义的方法访问。

如果没有指定名称的属性，或者如果指定名称为空或null，则返回false。

1 语法

public static boolean getBoolean(String name)

2 参数

name：系统属性名称

3 返回值

此方法返回系统属性的布尔值。

4 示例 

package com.yiidian;

/**
 * 一点教程网： http://www.yiidian.com
 */
/**
 * Java Boolean getBoolean()方法
 */
import java.lang.*;

public class BooleanDemo {

   public static void main(String[] args) {

      // create 2 boolean primitives bool1, bool2
      boolean bool1, bool2;

      /**
       *  using System class's setProprty method, set the values of
       *  system properties demo1, demo2.
       */
      System.setProperty("demo1","true");
      System.setProperty("demo2","abcd");

      // retrieve value of system properties to s1, s2
      String s1 = System.getProperty("demo1");
      String s2 = System.getProperty("demo2");

      // assign result of getBoolean on demo1, demo2 to bool1, bool2
      bool1 = Boolean.getBoolean("demo1");
      bool2 = Boolean.getBoolean("demo2");

      String str1 = "boolean value of system property demo1 is " + bool1;
      String str2 = "System property value of demo1 is " + s1;
      String str3 = "boolean value of system property demo2 is " + bool2;
      String str4 = "System property value of demo2 is " + s2;

      // print bool1, bool2 and s1, s2 values
      System.out.println( str1 );
      System.out.println( str2 );
      System.out.println( str3 );
      System.out.println( str4 );
   }
}

输出结果为：

boolean value of system property demo1 is true
System property value of demo1 is true
boolean value of system property demo2 is false
System property value of demo2 is abcd