添加CSV的BOM解析支持

easyexcel-core/src/main/java/com/alibaba/excel/analysis/csv/BomBufferedInputStream.java

@@ -0,0 +1,91 @@
+package com.alibaba.excel.analysis.csv;
+
+
+import java.io.BufferedInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * This class is used to wrap a stream that includes an encoded {@link ByteOrderMark} as its first bytes.
+ *
+ * @author supalle
+ * @see <a href="http://unicode.org/faq/utf_bom.html#BOM">Byte Order Mark (BOM) FAQ</a>
+ * @see <a href="https://commons.apache.org/proper/commons-io/apidocs/org/apache/commons/io/ByteOrderMark.html">Apache CommonsIO BOMInputStream</a>
+ */
+public class BomBufferedInputStream extends BufferedInputStream {
+    public final static List<ByteOrderMark> DEFAULT_BYTE_ORDER_MARKS = new ArrayList<>();
+
+    static {
+        DEFAULT_BYTE_ORDER_MARKS.add(ByteOrderMark.UTF_8);
+        DEFAULT_BYTE_ORDER_MARKS.add(ByteOrderMark.UTF_16BE);
+        DEFAULT_BYTE_ORDER_MARKS.add(ByteOrderMark.UTF_16LE);
+        DEFAULT_BYTE_ORDER_MARKS.add(ByteOrderMark.UTF_32BE);
+        DEFAULT_BYTE_ORDER_MARKS.add(ByteOrderMark.UTF_32LE);
+    }
+
+    private boolean initialized;
+    private ByteOrderMark byteOrderMark;
+    private final List<ByteOrderMark> byteOrderMarks;
+
+    public BomBufferedInputStream(InputStream in, final ByteOrderMark... byteOrderMarks) {
+        super(in);
+        this.byteOrderMarks = applyByteOrderMarks(byteOrderMarks);
+    }
+
+    public BomBufferedInputStream(InputStream in, int size, final ByteOrderMark... byteOrderMarks) {
+        super(in, size);
+        this.byteOrderMarks = applyByteOrderMarks(byteOrderMarks);
+    }
+
+    private static List<ByteOrderMark> applyByteOrderMarks(ByteOrderMark[] byteOrderMarks) {
+        return byteOrderMarks == null || byteOrderMarks.length == 0 ? DEFAULT_BYTE_ORDER_MARKS : Arrays.asList(byteOrderMarks);
+    }
+
+    public boolean hasByteOrderMark() throws IOException {
+        return getByteOrderMark() != null;
+    }
+
+    public ByteOrderMark getByteOrderMark() throws IOException {
+        if (initialized) {
+            return byteOrderMark;
+        }
+        this.byteOrderMarks.sort(ByteOrderMark::compareTo);
+        int maxBomLength = byteOrderMarks.get(0).length();
+        mark(maxBomLength);
+        int[] firstBytes = new int[maxBomLength];
+        for (int i = 0; i < maxBomLength; i++) {
+            firstBytes[i] = read();
+            if (firstBytes[i] < 0) {
+                break;
+            }
+        }
+        byteOrderMark = matchByteOrderMark(this.byteOrderMarks, firstBytes);
+
+        reset();
+        if (byteOrderMark != null) {
+            // read(new byte[byteOrderMark.length()]);
+            skip(byteOrderMark.length());
+        }
+        initialized = true;
+        return byteOrderMark;
+    }
+
+    private ByteOrderMark matchByteOrderMark(final List<ByteOrderMark> byteOrderMarks, final int[] firstBytes) {
+        loop:
+        for (ByteOrderMark item : byteOrderMarks) {
+            int[] bytes = item.getBytes();
+            int length = bytes.length;
+            for (int i = 0; i < length; i++) {
+                if (firstBytes[i] != bytes[i]) {
+                    continue loop;
+                }
+            }
+            return item;
+        }
+        return null;
+    }
+
+}

easyexcel-core/src/main/java/com/alibaba/excel/analysis/csv/ByteOrderMark.java

@@ -0,0 +1,112 @@
+package com.alibaba.excel.analysis.csv;
+
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
+import java.util.Objects;
+import java.util.stream.Collectors;
+
+/**
+ * Byte Order Mark (BOM)
+ * <br/>
+ * User in {@link BomBufferedInputStream}
+ *
+ * @author supalle
+ * @see <a href="http://unicode.org/faq/utf_bom.html#BOM">Byte Order Mark (BOM) FAQ</a>
+ * @see <a href="https://commons.apache.org/proper/commons-io/apidocs/org/apache/commons/io/ByteOrderMark.html">Apache CommonsIO ByteOrderMark</a>
+ */
+public class ByteOrderMark implements Comparable<ByteOrderMark> {
+
+    /**
+     * UTF-8 BOM.
+     */
+    public static final ByteOrderMark UTF_8 = new ByteOrderMark(StandardCharsets.UTF_8, 0xEF, 0xBB, 0xBF);
+
+    /**
+     * UTF-16BE BOM (Big-Endian).
+     */
+    public static final ByteOrderMark UTF_16BE = new ByteOrderMark(StandardCharsets.UTF_16BE, 0xFE, 0xFF);
+
+    /**
+     * UTF-16LE BOM (Little-Endian).
+     */
+    public static final ByteOrderMark UTF_16LE = new ByteOrderMark(StandardCharsets.UTF_16LE, 0xFF, 0xFE);
+
+    /**
+     * UTF-32BE BOM (Big-Endian).
+     *
+     * @since 2.2
+     */
+    public static final ByteOrderMark UTF_32BE = new ByteOrderMark(Charset.forName("UTF-32BE"), 0x00, 0x00, 0xFE, 0xFF);
+
+    /**
+     * UTF-32LE BOM (Little-Endian).
+     *
+     * @since 2.2
+     */
+    public static final ByteOrderMark UTF_32LE = new ByteOrderMark(Charset.forName("UTF-32LE"), 0xFF, 0xFE, 0x00, 0x00);
+
+    /**
+     * Unicode BOM character; external form depends on the encoding.
+     *
+     * @see <a href="http://unicode.org/faq/utf_bom.html#BOM">Byte Order Mark (BOM) FAQ</a>
+     * @since 2.5
+     */
+    public static final char UTF_BOM = '\uFEFF';
+
+    private final Charset charset;
+    private final int[] bytes;
+
+    public ByteOrderMark(final Charset charset, final int... bytes) {
+        this.charset = Objects.requireNonNull(charset, "charset must be not null");
+        if (bytes == null || bytes.length == 0) {
+            throw new IllegalArgumentException("bytes must be not empty");
+        }
+        this.bytes = bytes;
+    }
+
+    public Charset getCharset() {
+        return charset;
+    }
+
+    public int[] getBytes() {
+        return bytes;
+    }
+
+    public int length() {
+        return bytes.length;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ByteOrderMark that = (ByteOrderMark) o;
+        return Objects.equals(charset, that.charset) && Arrays.equals(bytes, that.bytes);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = Objects.hash(charset);
+        result = 31 * result + Arrays.hashCode(bytes);
+        return result;
+    }
+
+    @Override
+    public String toString() {
+        return "ByteOrderMark{" +
+            "charset=" + charset +
+            ", bytes=["
+            + Arrays.stream(bytes)
+            .mapToObj(Integer::toHexString)
+            .map(String::toUpperCase)
+            .map("0x"::concat)
+            .collect(Collectors.joining(",")) +
+            "]}";
+    }
+
+    @Override
+    public int compareTo(ByteOrderMark o) {
+        return o.length() - length();
+    }
+}

easyexcel-core/src/main/java/com/alibaba/excel/read/metadata/holder/csv/CsvReadWorkbookHolder.java

@@ -1,15 +1,18 @@
 package com.alibaba.excel.read.metadata.holder.csv;
 
+import com.alibaba.excel.analysis.csv.BomBufferedInputStream;
 import com.alibaba.excel.read.metadata.ReadWorkbook;
 import com.alibaba.excel.read.metadata.holder.ReadWorkbookHolder;
 import com.alibaba.excel.support.ExcelTypeEnum;
-
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
 import lombok.Setter;
 import org.apache.commons.csv.CSVFormat;
 import org.apache.commons.csv.CSVParser;
 
+import java.io.IOException;
+import java.nio.file.Files;
+
 /**
  * Workbook holder
  *
@@ -27,5 +30,34 @@ public class CsvReadWorkbookHolder extends ReadWorkbookHolder {
         super(readWorkbook);
         setExcelType(ExcelTypeEnum.CSV);
         this.csvFormat = CSVFormat.DEFAULT;
+        // CSV BOM
+        if (readWorkbook.getCharset() == null) {
+            BomBufferedInputStream bomBufferedInputStream = buildBomBufferedInputStream();
+            setInputStream(bomBufferedInputStream);
+            setMandatoryUseInputStream(Boolean.TRUE);
+            try {
+                if (bomBufferedInputStream.hasByteOrderMark()) {
+                    setCharset(bomBufferedInputStream.getByteOrderMark().getCharset());
+                }
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        }
+    }
+
+    private BomBufferedInputStream buildBomBufferedInputStream() {
+        BomBufferedInputStream bomBufferedInputStream;
+        try {
+            if (Boolean.TRUE.equals(getMandatoryUseInputStream())) {
+                bomBufferedInputStream = new BomBufferedInputStream(getInputStream());
+            } else if (getFile() != null) {
+                bomBufferedInputStream = new BomBufferedInputStream(Files.newInputStream(getFile().toPath()));
+            } else {
+                bomBufferedInputStream = new BomBufferedInputStream(getInputStream());
+            }
+        } catch (IOException e) {
+            throw new RuntimeException(e.getMessage());
+        }
+        return bomBufferedInputStream;
     }
 }

easyexcel-test/src/test/java/com/alibaba/easyexcel/test/core/bom/BomData.java

@@ -0,0 +1,16 @@
+package com.alibaba.easyexcel.test.core.bom;
+
+import com.alibaba.excel.annotation.ExcelProperty;
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
+@EqualsAndHashCode
+public class BomData {
+    @ExcelProperty("姓名")
+    private String name;
+    @ExcelProperty("年纪")
+    private Integer age;
+}

easyexcel-test/src/test/java/com/alibaba/easyexcel/test/core/bom/BomDataTest.java

@@ -0,0 +1,53 @@
+package com.alibaba.easyexcel.test.core.bom;
+
+import com.alibaba.easyexcel.test.util.TestFileUtil;
+import com.alibaba.excel.EasyExcel;
+import com.alibaba.excel.context.AnalysisContext;
+import com.alibaba.excel.metadata.data.ReadCellData;
+import com.alibaba.excel.read.listener.ReadListener;
+import org.apache.commons.compress.utils.Lists;
+import org.junit.Assert;
+import org.junit.FixMethodOrder;
+import org.junit.Test;
+import org.junit.runners.MethodSorters;
+
+import java.io.File;
+import java.util.List;
+import java.util.Map;
+
+@FixMethodOrder(MethodSorters.NAME_ASCENDING)
+public class BomDataTest {
+    @Test
+    public void t01ReadAndWriteCsv() {
+        readCsv(TestFileUtil.readFile("bom" + File.separator + "bom_none.csv"));
+        readCsv(TestFileUtil.readFile("bom" + File.separator + "bom_utf8.csv"));
+        readCsv(TestFileUtil.readFile("bom" + File.separator + "bom_utf16be.csv"));
+        readCsv(TestFileUtil.readFile("bom" + File.separator + "bom_utf16le.csv"));
+    }
+
+    private void readCsv(File file) {
+        EasyExcel.read(file, BomData.class, new ReadListener<BomData>() {
+
+            private final List<BomData> dataList = Lists.newArrayList();
+
+            @Override
+            public void invokeHead(Map<Integer, ReadCellData<?>> headMap, AnalysisContext context) {
+                String head = headMap.get(0).getStringValue();
+                Assert.assertEquals("姓名", head);
+            }
+
+            @Override
+            public void invoke(BomData data, AnalysisContext context) {
+                dataList.add(data);
+            }
+
+            @Override
+            public void doAfterAllAnalysed(AnalysisContext context) {
+                Assert.assertEquals(dataList.size(), 10);
+                BomData bomData = dataList.get(0);
+                Assert.assertEquals("姓名0", bomData.getName());
+                Assert.assertEquals(0, (long) bomData.getAge());
+            }
+        }).sheet().doRead();
+    }
+}

easyexcel-test/src/test/resources/bom/bom_none.csv

@@ -0,0 +1,11 @@
+姓名,年纪
+姓名0,0
+姓名1,1
+姓名2,2
+姓名3,3
+姓名4,4
+姓名5,5
+姓名6,6
+姓名7,7
+姓名8,8
+姓名9,9

easyexcel-test/src/test/resources/bom/bom_utf8.csv

@@ -0,0 +1,11 @@
+姓名,年纪
+姓名0,0
+姓名1,1
+姓名2,2
+姓名3,3
+姓名4,4
+姓名5,5
+姓名6,6
+姓名7,7
+姓名8,8
+姓名9,9