Guava 简明教程
Guava - Throwables Class
Throwable 类提供了与 Throwable 接口相关的实用方法。
Class Declaration
以下是 com.google.common.base.Throwables 类的声明 -
public final class Throwables
extends Object
Class Methods
Sr.No |
Method & Description |
1 |
static List<Throwable> getCausalChain(Throwable throwable) 获取 Throwable 原因链作为列表。 |
2 |
static Throwable getRootCause(Throwable throwable) 返回 Throwable 的最里层原因。 |
3 |
static String getStackTraceAsString(Throwable throwable) 返回一个字符串,其中包含 toString() 的结果,后跟 Throwable 的完整递归堆栈跟踪。 |
4 |
static RuntimeException propagate(Throwable throwable) 如果 Throwable 是 RuntimeException 或 Error 的实例,则按原样传播它,否则作为最后的手段,用 RuntimeException 包装它,然后传播它。 |
5 |
static <X extends Throwable> void propagateIfInstanceOf(Throwable throwable, Class<X> declaredType) 当且仅当 Throwable 是 declaredType 的实例时,才按原样传播 Throwable。 |
6 |
static void propagateIfPossible(Throwable throwable) 当且仅当 Throwable 是 RuntimeException 或 Error 的实例时,才按原样传播 Throwable。 |
7 |
static <X extends Throwable> void propagateIfPossible(Throwable throwable, Class<X> declaredType) 当且仅当 Throwable 是 RuntimeException、Error 或 declaredType 的实例时,才按原样传播 Throwable。 |
8 |
static <X1 extends Throwable,X2 extends Throwable>void propagateIfPossible(Throwable throwable, Class<X1> declaredType1, Class<X2> declaredType2) 当且仅当 Throwable 是 RuntimeException、Error、declaredType1 或 declaredType2 的实例时,才按原样传播 Throwable。 |
Example of Throwables Class
使用任意你选择的编辑器在 C:/> Guava. 中创建以下 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 {
}
Verify the Result
按照如下方式使用 javac 编译器编译类 −
C:\Guava>javac GuavaTester.java
现在运行 GuavaTester 以查看结果。
C:\Guava>java GuavaTester
查看结果。
InvalidInputException
java.lang.ArrayIndexOutOfBoundsException: 4
at GuavaTester.getValue(GuavaTester.java:52)
at GuavaTester.showcaseThrowables1(GuavaTester.java:38)
at GuavaTester.main(GuavaTester.java:19)