java中的除数为零问题

今天在项目中遇到了一个除零的问题，很是惊奇。最后结果发现在java中浮点数运算中0作除数并不会出现异常，而是结果为：正数除以0得正无穷，负数除以0得负无穷，0除以0得NaN；同样情况若是整形数运算则会抛出异常。从网上找了一个测试的例子与大家分享一下：

public class DivideTest {

 public static void main(String[] args) {
  DivideTest dt = new DivideTest();
  
  // 整数
  dt.testInt(0, 0);
  dt.testInt(1, 0);
  dt.testInt(-1, 0);
  
  // 长整形
  dt.testLong(0, 0);
  dt.testLong(1, 0);
  dt.testLong(-1, 0);
  
  // 浮点
  dt.testFloat(0, 0);
  dt.testFloat(1, 0);
  dt.testFloat(-1, 0);
  
  // 双精度
  dt.testDouble(0, 0);
  dt.testDouble(1, 0);
  dt.testDouble(-1, 0);
  
  System.out.println("12>(0.0/0.0) "+(12>(0.0/0.0)));
  System.out.println("12>(0.1/0.0) "+(12>(0.1/0.0)));
  System.out.println("12<(0.0/0.0) "+(12<(0.0/0.0)));
  System.out.println("12<(0.1/0.0) "+(12<(0.1/0.0)));
  
  System.out.println("12==(0.0/0.0) "+(12==(0.0/0.0)));

 }

 private void testInt(int dividend, int divisor){
  try {
   System.out.println("testInt: "+dividend+"/"+divisor+" = "+dividend/divisor);
  } catch (RuntimeException e) {
   e.printStackTrace();
  }
 }
 
 private void testLong(long dividend, long divisor){
  try {
   System.out.println("testLong: "+dividend+"/"+divisor+" = "+dividend/divisor);
  } catch (RuntimeException e) {
   e.printStackTrace();
  }
 }
 
 private void testDouble(double dividend, double divisor){
  try {
   System.out.println("testDouble: "+dividend+"/"+divisor+" = "+dividend/divisor);
  } catch (RuntimeException e) {
   e.printStackTrace();
  }
 }
 
 private void testFloat(float dividend, float divisor){
  try {
   System.out.println("testFloat: "+dividend+"/"+divisor+" = "+dividend/divisor);
  } catch (RuntimeException e) {
   e.printStackTrace();
  }
 }

}
结果如下：
java.lang.ArithmeticException: / by zero
        at test.DivideTest.testInt(DivideTest.java:42)
        at test.DivideTest.main(DivideTest.java:12)
java.lang.ArithmeticException: / by zero
        at test.DivideTest.testInt(DivideTest.java:42)
        at test.DivideTest.main(DivideTest.java:13)
java.lang.ArithmeticException: / by zero
        at test.DivideTest.testInt(DivideTest.java:42)
        at test.DivideTest.main(DivideTest.java:14)
java.lang.ArithmeticException: / by zero
        at test.DivideTest.testLong(DivideTest.java:50)
        at test.DivideTest.main(DivideTest.java:17)
java.lang.ArithmeticException: / by zero
        at test.DivideTest.testLong(DivideTest.java:50)
        at test.DivideTest.main(DivideTest.java:18)
java.lang.ArithmeticException: / by zero
        at test.DivideTest.testLong(DivideTest.java:50)
        at test.DivideTest.main(DivideTest.java:19)
testFloat: 0.0/0.0 = NaN
testFloat: 1.0/0.0 = Infinity
testFloat: -1.0/0.0 = -Infinity
testDouble: 0.0/0.0 = NaN
testDouble: 1.0/0.0 = Infinity
testDouble: -1.0/0.0 = -Infinity
12>(0.0/0.0) false
12>(0.1/0.0) false
12<(0.0/0.0) false
12<(0.1/0.0) true
12==(0.0/0.0) false