public class CleanUtil { public static void deleleFilesOfDir(String dirPathName, int retainHours) { File dir = new File(dirPathName); File[] listFile = dir.listFiles(); if (listFile == null) { return; } long now = System.currentTimeMillis(); for (File file : listFile) { deleteFile(now, retainHours, file); } } private static void deleteFile(long now, int retainHours, File file) { try { BasicFileAttributes basicAttr = Files.readAttributes(file.toPath(), BasicFileAttributes.class); long fileTime = basicAttr.lastAccessTime().toMillis(); deleteOverDueFile(retainHours, file, now, fileTime); } catch (IOException | RuntimeException e) { log.warn("failed to read file attributes: {}", file.getAbsolutePath(), e); } } private static void deleteOverDueFile(int retainHours, File file, long now, long fileTime) { if (isOverDue(retainHours, now, fileTime)) { boolean isDeleted = FileUtils.deleteQuietly(file); if (!isDeleted) { log.warn("file deleted faild: {}", file.getAbsolutePath()); } } }需要你这边写UT覆盖，包括异常测试

好的，我可以为这段代码编写一些单元测试，包括正常情况和异常情况的覆盖。下面是一个简单的示例，供您参考：

import org.apache.commons.io.FileUtils;
import org.junit.jupiter.api.Test;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.attribute.BasicFileAttributes;

import static org.junit.jupiter.api.Assertions.*;
import static org.mockito.Mockito.*;

public class CleanUtilTest {
    
    @Test
    public void testDeleteFilesOfDir() throws IOException {
        File dir = mock(File.class);
        File[] listFile = new File[] {
            mock(File.class),
            mock(File.class),
            mock(File.class)
        };
        when(dir.listFiles()).thenReturn(listFile);
        when(listFile[0].toPath()).thenReturn(mock(java.nio.file.Path.class));
        when(listFile[0].getAbsolutePath()).thenReturn("file1");
        when(listFile[1].toPath()).thenReturn(mock(java.nio.file.Path.class));
        when(listFile[1].getAbsolutePath()).thenReturn("file2");
        when(listFile[2].toPath()).thenReturn(mock(java.nio.file.Path.class));
        when(listFile[2].getAbsolutePath()).thenReturn("file3");
        
        CleanUtil.deleleFilesOfDir(dir.getAbsolutePath(), 1);
        
        verify(listFile[0]).delete();
        verify(listFile[1]).delete();
        verify(listFile[2]).delete();
    }
    
    @Test
    public void testDeleteFilesOfDirWithNullList() throws IOException {
        File dir = mock(File.class);
        when(dir.listFiles()).thenReturn(null);
        
        CleanUtil.deleleFilesOfDir(dir.getAbsolutePath(), 1);
        
        verifyNoMoreInteractions(dir);
    }
    
    @Test
    public void testDeleteFilesOfDirWithReadAttrException() throws IOException {
        File dir = mock(File.class);
        File[] listFile = new File[] {
            mock(File.class),
            mock(File.class),
            mock(File.class)
        };
        when(dir.listFiles()).thenReturn(listFile);
        when(listFile[0].toPath()).thenReturn(mock(java.nio.file.Path.class));
        when(listFile[0].getAbsolutePath()).thenReturn("file1");
        when(listFile[1].toPath()).thenReturn(mock(java.nio.file.Path.class));
        when(listFile[1].getAbsolutePath()).thenReturn("file2");
        when(listFile[2].toPath()).thenReturn(mock(java.nio.file.Path.class));
        when(listFile[2].getAbsolutePath()).thenReturn("file3");
        when(Files.readAttributes(any(), eq(BasicFileAttributes.class)))
            .thenThrow(new IOException("failed to read attributes"));
        
        CleanUtil.deleleFilesOfDir(dir.getAbsolutePath(), 1);
        
        verify(listFile[0], never()).delete();
        verify(listFile[1], never()).delete();
        verify(listFile[2], never()).delete();
    }
    
    @Test
    public void testDeleteOverDueFile() throws IOException {
        File file = mock(File.class);
        when(file.toPath()).thenReturn(mock(java.nio.file.Path.class));
        when(file.getAbsolutePath()).thenReturn("file1");
        when(file.lastModified()).thenReturn(System.currentTimeMillis() - 3600 * 1000);
        
        CleanUtil.deleteOverDueFile(1, file, System.currentTimeMillis(), file.lastModified());
        
        verify(file).delete();
    }
    
    @Test
    public void testDeleteOverDueFileWithNotOverdue() throws IOException {
        File file = mock(File.class);
        when(file.toPath()).thenReturn(mock(java.nio.file.Path.class));
        when(file.getAbsolutePath()).thenReturn("file1");
        when(file.lastModified()).thenReturn(System.currentTimeMillis() - 1000);
        
        CleanUtil.deleteOverDueFile(1, file, System.currentTimeMillis(), file.lastModified());
        
        verify(file, never()).delete();
    }
    
    @Test
    public void testDeleteOverDueFileWithDeleteFailed() throws IOException {
        File file = mock(File.class);
        when(file.toPath()).thenReturn(mock(java.nio.file.Path.class));
        when(file.getAbsolutePath()).thenReturn("file1");
        when(file.lastModified()).thenReturn(System.currentTimeMillis() - 3600 * 1000);
        when(FileUtils.deleteQuietly(file)).thenReturn(false);
        
        CleanUtil.deleteOverDueFile(1, file, System.currentTimeMillis(), file.lastModified());
        
        verify(file).delete();
    }
    
    @Test
    public void testDeleteFileWithRuntimeException() throws IOException {
        File file = mock(File.class);
        when(file.toPath()).thenReturn(mock(java.nio.file.Path.class));
        when(file.getAbsolutePath()).thenReturn("file1");
        when(Files.readAttributes(any(), eq(BasicFileAttributes.class)))
            .thenThrow(new RuntimeException("failed to read attributes"));
        
        CleanUtil.deleteFile(System.currentTimeMillis(), 1, file);
        
        verify(file, never()).delete();
    }
    
    @Test
    public void testDeleteFileWithIOException() throws IOException {
        File file = mock(File.class);
        when(file.toPath()).thenReturn(mock(java.nio.file.Path.class));
        when(file.getAbsolutePath()).thenReturn("file1");
        when(Files.readAttributes(any(), eq(BasicFileAttributes.class)))
            .thenThrow(new IOException("failed to read attributes"));
        
        CleanUtil.deleteFile(System.currentTimeMillis(), 1, file);
        
        verify(file, never()).delete();
    }
    
}

这里使用了 Mockito 和 JUnit5，其中：

- testDeleteFilesOfDir 方法测试了正常情况下的文件删除；
- testDeleteFilesOfDirWithNullList 方法测试了当目录为空时不进行操作；
- testDeleteFilesOfDirWithReadAttrException 方法测试了读取文件属性时出现异常的情况；
- testDeleteOverDueFile 方法测试了删除过期文件的情况；
- testDeleteOverDueFileWithNotOverdue 方法测试了文件未过期时不进行操作的情况；
- testDeleteOverDueFileWithDeleteFailed 方法测试了删除文件失败的情况；
- testDeleteFileWithRuntimeException 和 testDeleteFileWithIOException 方法测试了读取文件属性时出现异常的情况。