有时候, 当我们我们捕获异常, 并且像把这个异常传递到下一个try/catch块中。Guava提供了一个异常处理工具类, 可以简单地捕获和重新抛出多个异常。
[code]import java.io.IOException; import org.junit.Test; import com.google.common.base.Throwables; public class ThrowablesTest { @Test public void testThrowables(){ try { throw new Exception(); } catch (Throwable t) { String ss = Throwables.getStackTraceAsString(t); System.out.println("ss:"+ss); Throwables.propagate(t); } } @Test public void call() throws IOException { try { throw new IOException(); } catch (Throwable t) { Throwables.propagateIfInstanceOf(t, IOException.class); throw Throwables.propagate(t); } } }
将检查异常转换成未检查异常,例如:
[code]import java.io.InputStream; import java.net.URL; import org.junit.Test; import com.google.common.base.Throwables; public class ThrowablesTest { @Test public void testCheckException(){ try { URL url = new URL("http://ociweb.com"); final InputStream in = url.openStream(); // read from the input stream in.close(); } catch (Throwable t) { throw Throwables.propagate(t); } } }
传递异常的常用方法:
1.RuntimeException propagate(Throwable):把throwable包装成RuntimeException,用该方法保证异常传递,抛出一个RuntimeException异常
2.void propagateIfInstanceOf(Throwable, Class) throws X:当且仅当它是一个X的实例时,传递throwable
3.void propagateIfPossible(Throwable):当且仅当它是一个RuntimeException和Error时,传递throwable
4.void propagateIfPossible(Throwable, Class) throws X:当且仅当它是一个RuntimeException和Error时,或者是一个X的实例时,传递throwable。
[code]import java.io.IOException; import org.junit.Test; import com.google.common.base.Throwables; public class ThrowablesTest { @Test public void testThrowables(){ try { throw new Exception(); } catch (Throwable t) { String ss = Throwables.getStackTraceAsString(t); System.out.println("ss:"+ss); Throwables.propagate(t); } } @Test public void call() throws IOException { try { throw new IOException(); } catch (Throwable t) { Throwables.propagateIfInstanceOf(t, IOException.class); throw Throwables.propagate(t); } } public Void testPropagateIfPossible() throws Exception { try { throw new Exception(); } catch (Throwable t) { Throwables.propagateIfPossible(t, Exception.class); Throwables.propagate(t); } return null; } }
Guava的异常链处理方法:
1.Throwable getRootCause(Throwable)
2.List getCausalChain(Throwable)
3.String getStackTraceAsString(Throwable)
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