Guava：Throwables 异常工具

Guava Throwables 类

Throwable 类，简化异常和错误的传播与检查

类方法说明

官方文档：Throwables (Guava: Google Core Libraries for Java 27.0.1-jre API)

方法类型	方法描述
static List	getCausalChain(Throwable throwable)  获取一个Throwable的原因链的列表.
static X	getCauseAs(Throwable throwable, Class expectedCauseType)  返回throwable的原因，强制转换为expectedCauseType.
static Throwable	getRootCause(Throwable throwable)  返回抛出的最里面的原因.
static String	getStackTraceAsString(Throwable throwable)  返回包含toString()的结果字符串，随后完整抛出，递归的堆栈跟踪。
static List	lazyStackTrace(Throwable throwable)  返回throwable的堆栈跟踪，可能在整个跟踪上提供较慢的迭代，但在部分跟踪上的迭代速度更快.
static boolean	lazyStackTraceIsLazy()  返回lazyStackTrace（java.lang.Throwable）是否将使用其文档中描述的特殊实现。
static RuntimeException	propagate(Throwable throwable)  把throwable包装成RuntimeException，用该方法保证异常传递，抛出一个RuntimeException异常.
static void	propagateIfInstanceOf(@Nullable Throwable throwable, ClassdeclaredType)  Throwable类型为X才抛出.
static void	propagateIfPossible(@Nullable Throwable throwable)  Throwable类型为Error或RuntimeException才抛出。
static void	propagateIfPossible(@Nullable Throwable throwable, ClassdeclaredType)  Throwable类型为X, Error或RuntimeException才抛出.
static void	throwIfInstanceOf(Throwable throwable, Class declaredType)  如果是declaredType的实例，则抛出throwable.
static void	throwIfUnchecked(Throwable throwable)  如果是RuntimeException或Error，则抛出throwable.

测试Demo

import com.google.common.base.Throwables;
import org.junit.Test;

import java.io.IOException;
import java.util.List;

public class ThrowablesTests {

    public void getException(){
        int[] data = {1, 2, 3};
        int datum = data[4];
    }

    @Test
    public void test1() {
        try {
            getException();
        } catch (Exception e) {
            List causalChain = Throwables.getCausalChain(e);
            System.out.println(causalChain);
        }
    }

    @Test
    public void test2() {
        try {
            // 模拟抛出一个异常
            throw new IOException("An I/O error occurred");
        } catch (Exception e) {
            // 获取异常的原因，并检查是否为 IOException 类型或其子类型
            Throwable cause = Throwables.getCauseAs(e, IOException.class);
            if (cause != null) {
                System.out.println("Cause is an IOException: " + cause.getMessage());
            } else {
                System.out.println("Cause is not an IOException");
            }
        }
    }

    @Test
    public void test3() {
        try {
            // 模拟抛出一个嵌套多层的异常
            throw new IOException("An I/O error occurred");
        } catch (Exception e) {
            Throwable rootCause = Throwables.getRootCause(e);
            String stackTraceAsString = Throwables.getStackTraceAsString(rootCause);
            System.out.println(stackTraceAsString);
        }
    }
}