方法类| Java 中的 getExceptionTypes()方法
原文:https://www . geesforgeks . org/method-class-getexceptiontypes-method-in-Java/
“方法类”的Java . lang . reflect. Method . getexceptiontypes()方法返回一个由方法对象声明为抛出的异常类型类对象数组，以处理方法内部的异常。使用抛出子句的方法处理的所有异常都将使用此方法作为类对象的数组返回。如果应用此方法的方法在其 throws 子句中未声明任何异常，则此方法返回长度为 0 的数组。
语法:
public Class<?>[] getExceptionTypes()
返回值:这个方法返回一个异常类的数组，这个异常类是由 This method 对象使用 thrown 子句声明的
下面的程序说明了方法类的 getExceptionTypes()方法:
示例 1: 打印所有异常
/*
* Program Demonstrate getExceptionTypes() method
* of Method Class.
*/
import java.lang.reflect.Method;
public class GFG {
// Main method
public static void main(String[] args)
{
try {
// create class object
Class classobj = demoClass.class;
// get list of method Objects
Method[] methods = classobj.getMethods();
// loop through list
for (Method method : methods) {
// check for method with there name
if (method.getName().equals("setValue")
|| method.getName().equals("getValue")) {
// get Exception Types
Class[] exceptions = method.getExceptionTypes();
// print exception Types thrown by method Object
System.out.println("Exception Thrown by Method: "
+ method.getName());
System.out.println("Exception Array length: "
+ exceptions.length);
for (Class c : exceptions) {
System.out.println(c.getName());
}
}
}
}
catch (Exception e) {
e.printStackTrace();
}
}
}
// a simple class
class demoClass {
// throw some exception by method
public void setValue(String value)
throws ClassNotFoundException,
ArrayIndexOutOfBoundsException,
ArithmeticException
{
}
// method throwing no exception
public String getValue(String value)
{
return value;
}
}
Output:
Exception Thrown by Method: getValue
Exception Array length: 0
Exception Thrown by Method: setValue
Exception Array length: 3
java.lang.ClassNotFoundException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArithmeticException
示例 2: 检查方法对象是否抛出了某个定义的异常。如果是，则打印真，否则打印假。
// Program Demonstrate getExceptionTypes() method
// Using getExceptionTypes() method of Method Class
import java.lang.reflect.Method;
// a simple class
class GFGSampleClass {
String value;
// throw some exception by method
public void setValue(String value)
throws ClassNotFoundException,
ArrayIndexOutOfBoundsException,
ArithmeticException
{
this.value = value;
}
}
public class GFG {
// Main method
public static void main(String[] args)
{
try {
// create class object
Class classobj = GFGSampleClass.class;
// get list of method Objects
Method[] methods = classobj.getMethods();
// loop through list
for (Method method : methods) {
// check for method with there name
if (method.getName().equals("setValue")) {
// check whether method throw
// IndexOutOfBoundsException Exception
Class exceptionObj = IndexOutOfBoundsException.class;
boolean response = isCertainExceptionIsThrown(method,
exceptionObj);
System.out.println("IndexOutOfBoundsException is "
+ "thrown by setValue(): " + response);
}
}
}
catch (Exception e) {
e.printStackTrace();
}
}
/*
* Return true if the given method throws the
* exception passed as Parameter.
*/
private static boolean
isCertainExceptionIsThrown(Method method, Class<?> exceptionName)
{
// get all exception list
Class exceptions[] = method.getExceptionTypes();
for (int i = 0; i < exceptions.length; i++) {
// check exception thrown or not
if (exceptions[i] == exceptionName) {
return true;
}
}
return false;
}
}
Output:
IndexOutOfBoundsException is thrown by setValue(): false
参考: https://docs . Oracle . com/javase/8/docs/API/Java/lang/reflect/method . html # getExceptionTypes–
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