###40.4.3 OutputCapture `OutputCapture`是JUnit的一个`Rule`，用于捕获`System.out`和`System.err`输出，只需简单的将`@Rule`注解capture，然后在断言中调用`toString()`： ```java import org.junit.Rule; import org.junit.Test; import org.springframework.boot.test.OutputCapture; import static org.hamcrest.Matchers.*; import static org.junit.Assert.*; public class MyTest { @Rule public OutputCapture capture = new OutputCapture(); @Test public void testName() throws Exception { System.out.println("Hello World!"); assertThat(capture.toString(), containsString("World")); } } ```