Guava – Throwables 类
Throwables类提供了与Throwable接口相关的实用方法
Throwables 类声明
以下是 com.google.common.base.Throwables 类的声明 −
public final class Throwables extends Object
Throwables 类函数
| Sr.No | Method & Description |
|---|---|
| 1 | static List<Throwable> getCausalChain(Throwable throwable) 获取一个Throwable原因链，作为一个列表. |
| 2 | static Throwable getRootCause(Throwable throwable) 返回throwable的最内部原因. |
| 3 | static String getStackTraceAsString(Throwable throwable) 返回一个包含toString()结果的字符串，后面是完整的、递归的、throwable堆栈跟踪. |
| 4 | static RuntimeException propagate(Throwable throwable) 如果throwable是RuntimeException或Error的实例，则按原样传播，否则作为最后手段，将其包装成RuntimeException，然后传播. |
| 5 | static <X extends Throwable> void propagateIfInstanceOf(Throwable throwable, Class<X> declaredType) 当且仅当它是 declaredType 的一个实例时，完全按原样传播 throwable. |
| 6 | static void propagateIfPossible(Throwable throwable) 当且仅当它是RuntimeException或Error的实例时，完全按原样传播throwable. |
| 7 | static <X extends Throwable> void propagateIfPossible(Throwable throwable, Class<X> declaredType) 当且仅当它是RuntimeException、Error或diledType的实例时，完全按原样传播throwable. |
| 8 | static <X1 extends Throwable,X2 extends Throwable>void propagateIfPossible(Throwable throwable, Class<X1> declaredType1, Class<X2> declaredType2) 当且仅当它是RuntimeException、Error、predatedType1或predatedType2的实例时，才会完全按原样传播throwable. |
Throwables 类继承
该类继承了以下类的方法 −
java.lang.ObjectThrowables 类示例
在C:/>Guava中使用你选择的任何编辑器创建以下java程序
GuavaTester.java
import java.io.IOException;import com.google.common.base.Objects;import com.google.common.base.Throwables;public class GuavaTester { public static void main(String args[]) { GuavaTester tester = new GuavaTester(); try { tester.showcaseThrowables(); } catch (InvalidInputException e) { //get the root cause System.out.println(Throwables.getRootCause(e)); } catch (Exception e) { //get the stack trace in string format System.out.println(Throwables.getStackTraceAsString(e)); } try { tester.showcaseThrowables1(); } catch (Exception e) { System.out.println(Throwables.getStackTraceAsString(e)); } } public void showcaseThrowables() throws InvalidInputException { try { sqrt(-3.0); } catch (Throwable e) { //check the type of exception and throw it Throwables.propagateIfInstanceOf(e, InvalidInputException.class); Throwables.propagate(e); } } public void showcaseThrowables1() { try { int[] data = {1,2,3}; getValue(data, 4); } catch (Throwable e) { Throwables.propagateIfInstanceOf(e, IndexOutOfBoundsException.class); Throwables.propagate(e); } } public double sqrt(double input) throws InvalidInputException { if(input < 0) throw new InvalidInputException(); return Math.sqrt(input); } public double getValue(int[] list, int index) throws IndexOutOfBoundsException { return list[index]; } public void dummyIO() throws IOException { throw new IOException(); }}class InvalidInputException extends Exception {}
Throwables 类验证结果
使用javac编译器编译该类，如下所示 −
C:\Guava>javac GuavaTester.java
现在运行GuavaTester来看看结果.
C:\Guava>java GuavaTester
查看结果.
InvalidInputExceptionjava.lang.ArrayIndexOutOfBoundsException: 4 at GuavaTester.getValue(GuavaTester.java:52) at GuavaTester.showcaseThrowables1(GuavaTester.java:38) at GuavaTester.main(GuavaTester.java:19)
