add tmp CsvParser2

hutool-poi/src/main/java/org/dromara/hutool/poi/csv/CsvParser2.java

@@ -0,0 +1,362 @@
+/*
+ * Copyright (c) 2013-2024 Hutool Team and hutool.cn
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.dromara.hutool.poi.csv;
+
+import org.dromara.hutool.core.collection.iter.ComputeIter;
+import org.dromara.hutool.core.io.IORuntimeException;
+import org.dromara.hutool.core.map.MapUtil;
+import org.dromara.hutool.core.text.CharUtil;
+import org.dromara.hutool.core.text.StrTrimer;
+import org.dromara.hutool.core.text.StrUtil;
+import org.dromara.hutool.core.util.ObjUtil;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.io.Reader;
+import java.io.Serializable;
+import java.util.*;
+
+/**
+ * CSV行解析器，参考：FastCSV
+ *
+ * @author Looly
+ */
+public final class CsvParser2 extends ComputeIter<CsvRow> implements Closeable, Serializable {
+	private static final long serialVersionUID = 1L;
+
+	private static final int DEFAULT_ROW_CAPACITY = 10;
+
+	private final CsvReadConfig config;
+	private final CsvTokener tokener;
+	/**
+	 * 前一个特殊分界字符
+	 */
+	private int preChar = -1;
+	/**
+	 * 是否在引号包装内
+	 */
+	private boolean inQuotes;
+	/**
+	 * 当前读取字段
+	 */
+	private final StringBuilder currentField = new StringBuilder(512);
+
+	/**
+	 * 标题行
+	 */
+	private CsvRow header;
+	/**
+	 * 当前行号
+	 */
+	private long lineNo = -1;
+	/**
+	 * 引号内的行数
+	 */
+	private long inQuotesLineCount;
+	/**
+	 * 第一行字段数，用于检查每行字段数是否一致
+	 */
+	private int firstLineFieldCount = -1;
+	/**
+	 * 最大字段数量，用于初始化行，减少扩容
+	 */
+	private int maxFieldCount;
+	/**
+	 * 是否读取结束
+	 */
+	private boolean finished;
+
+	/**
+	 * CSV解析器
+	 *
+	 * @param reader Reader
+	 * @param config 配置，null则为默认配置
+	 */
+	public CsvParser2(final Reader reader, final CsvReadConfig config) {
+		this.config = ObjUtil.defaultIfNull(config, CsvReadConfig::defaultConfig);
+		this.tokener = new CsvTokener(reader);
+	}
+
+	/**
+	 * 获取头部字段列表，如果headerLineNo &lt; 0，抛出异常
+	 *
+	 * @return 头部列表
+	 * @throws IllegalStateException 如果不解析头部或者没有调用nextRow()方法
+	 */
+	public List<String> getHeader() {
+		if (config.headerLineNo < 0) {
+			throw new IllegalStateException("No header available - header parsing is disabled");
+		}
+		if (lineNo < config.beginLineNo) {
+			throw new IllegalStateException("No header available - call nextRow() first");
+		}
+		return header.getRaw();
+	}
+
+	@Override
+	protected CsvRow computeNext() {
+		return nextRow();
+	}
+
+	/**
+	 * 读取下一行数据
+	 *
+	 * @return CsvRow
+	 * @throws IORuntimeException IO读取异常
+	 */
+	public CsvRow nextRow() throws IORuntimeException {
+		List<String> currentFields;
+		int fieldCount;
+		while (!finished) {
+			currentFields = readLine();
+			fieldCount = currentFields.size();
+			if (fieldCount < 1) {
+				// 空List表示读取结束
+				break;
+			}
+
+			// 读取范围校验
+			if (lineNo < config.beginLineNo) {
+				// 未达到读取起始行，继续
+				continue;
+			}
+			if (lineNo > config.endLineNo) {
+				// 超出结束行，读取结束
+				break;
+			}
+
+			// 跳过空行
+			if (config.skipEmptyRows && fieldCount == 1 && currentFields.get(0).isEmpty()) {
+				// [""]表示空行
+				continue;
+			}
+
+			// 检查每行的字段数是否一致
+			if (config.errorOnDifferentFieldCount) {
+				if (firstLineFieldCount < 0) {
+					firstLineFieldCount = fieldCount;
+				} else if (fieldCount != firstLineFieldCount) {
+					throw new IORuntimeException(String.format("Line %d has %d fields, but first line has %d fields", lineNo, fieldCount, firstLineFieldCount));
+				}
+			}
+
+			// 记录最大字段数
+			if (fieldCount > maxFieldCount) {
+				maxFieldCount = fieldCount;
+			}
+
+			//初始化标题
+			if (lineNo == config.headerLineNo && null == header) {
+				initHeader(currentFields);
+				// 作为标题行后，此行跳过，下一行做为第一行
+				continue;
+			}
+
+			return new CsvRow(lineNo, null == header ? null : header.headerMap, currentFields);
+		}
+
+		return null;
+	}
+
+	/**
+	 * 当前行做为标题行
+	 *
+	 * @param currentFields 当前行字段列表
+	 */
+	private void initHeader(final List<String> currentFields) {
+		final Map<String, Integer> localHeaderMap = new LinkedHashMap<>(currentFields.size());
+		for (int i = 0; i < currentFields.size(); i++) {
+			String field = currentFields.get(i);
+			if (MapUtil.isNotEmpty(this.config.headerAlias)) {
+				// 自定义别名
+				field = ObjUtil.defaultIfNull(this.config.headerAlias.get(field), field);
+			}
+			if (StrUtil.isNotEmpty(field) && !localHeaderMap.containsKey(field)) {
+				localHeaderMap.put(field, i);
+			}
+		}
+
+		header = new CsvRow(this.lineNo, Collections.unmodifiableMap(localHeaderMap), Collections.unmodifiableList(currentFields));
+	}
+
+	/**
+	 * 读取一行数据，如果读取结束，返回size为0的List<br>
+	 * 空行是size为1的List，唯一元素是""
+	 *
+	 * <p>
+	 * 行号要考虑注释行和引号包装的内容中的换行
+	 * </p>
+	 *
+	 * @return 一行数据
+	 * @throws IORuntimeException IO异常
+	 */
+	private List<String> readLine() throws IORuntimeException {
+		// 矫正行号
+		// 当一行内容包含多行数据时，记录首行行号，但是读取下一行时，需要把多行内容的行数加上
+		if (inQuotesLineCount > 0) {
+			this.lineNo += this.inQuotesLineCount;
+			this.inQuotesLineCount = 0;
+		}
+
+		final List<String> currentFields = new ArrayList<>(maxFieldCount > 0 ? maxFieldCount : DEFAULT_ROW_CAPACITY);
+
+		final StringBuilder currentField = this.currentField;
+		int preChar = this.preChar;//前一个特殊分界字符
+		boolean inComment = false;
+
+		int c;
+		while (true) {
+			c = tokener.next();
+			if(c < 0){
+				// 读取结束
+				this.finished = true;
+				break;
+			}
+
+			// 注释行标记
+			if (preChar < 0 || preChar == CharUtil.CR || preChar == CharUtil.LF) {
+				// 判断行首字符为指定注释字符的注释开始，直到遇到换行符
+				// 行首分两种，1是preChar < 0表示文本开始，2是换行符后紧跟就是下一行的开始
+				// issue#IA8WE0 如果注释符出现在包装符内，被认为是普通字符
+				if (!inQuotes && null != this.config.commentCharacter && c == this.config.commentCharacter) {
+					inComment = true;
+				}
+			}
+			// 注释行处理
+			if (inComment) {
+				if (c == CharUtil.CR || c == CharUtil.LF) {
+					// 注释行以换行符为结尾
+					lineNo++;
+					inComment = false;
+				}
+				// 跳过注释行中的任何字符
+				continue;
+			}
+
+			if (inQuotes) {
+				//引号内，作为内容，直到引号结束
+				if (c == config.textDelimiter) {
+					// End of quoted text
+					inQuotes = false;
+				} else {
+					// 字段内容中新行
+					if (isLineEnd(c, preChar)) {
+						inQuotesLineCount++;
+					}
+				}
+				// 普通字段字符
+				currentField.append((char)c);
+			} else {
+				// 非引号内
+				if (c == config.fieldSeparator) {
+					//一个字段结束
+					addField(currentFields, currentField.toString());
+					currentField.setLength(0);
+				} else if (c == config.textDelimiter && isFieldBegin(preChar)) {
+					// 引号开始且出现在字段开头
+					inQuotes = true;
+					currentField.append((char)c);
+				} else if (c == CharUtil.CR) {
+					// \r
+					addField(currentFields, currentField.toString());
+					currentField.setLength(0);
+					preChar = c;
+					break;
+				} else if (c == CharUtil.LF) {
+					// \n
+					if (preChar != CharUtil.CR) {
+						addField(currentFields, currentField.toString());
+						currentField.setLength(0);
+						preChar = c;
+						break;
+					}
+					// 前一个字符是\r，已经处理过这个字段了，此处直接跳过
+				} else {
+					currentField.append((char)c);
+				}
+			}
+
+			preChar = c;
+		}
+
+		// restore fields
+		this.preChar = preChar;
+
+		lineNo++;
+		return currentFields;
+	}
+
+	@Override
+	public void close() throws IOException {
+		tokener.close();
+	}
+
+	/**
+	 * 将字段加入字段列表并自动去包装和去转义
+	 *
+	 * @param currentFields 当前的字段列表（即为行）
+	 * @param field         字段
+	 */
+	private void addField(final List<String> currentFields, String field) {
+		final char textDelimiter = this.config.textDelimiter;
+
+		// 忽略多余引号后的换行符
+		field = StrUtil.trim(field, StrTrimer.TrimMode.SUFFIX, (c -> c == CharUtil.LF || c == CharUtil.CR));
+
+		if(StrUtil.isWrap(field, textDelimiter)){
+			field = StrUtil.sub(field, 1, field.length() - 1);
+			// https://datatracker.ietf.org/doc/html/rfc4180#section-2
+			// 第七条规则，只有包装内的包装符需要转义
+			field = StrUtil.replace(field, String.valueOf(textDelimiter) + textDelimiter, String.valueOf(textDelimiter));
+		}
+		if (this.config.trimField) {
+			// issue#I49M0C@Gitee
+			field = StrUtil.trim(field);
+		}
+		currentFields.add(field);
+	}
+
+	/**
+	 * 是否行结束符
+	 *
+	 * @param c       符号
+	 * @param preChar 前一个字符
+	 * @return 是否结束
+	 * @since 5.7.4
+	 */
+	private boolean isLineEnd(final int c, final int preChar) {
+		return (c == CharUtil.CR || c == CharUtil.LF) && preChar != CharUtil.CR;
+	}
+
+	/**
+	 * 通过前一个字符，判断是否字段开始，几种情况：
+	 * <ul>
+	 *     <li>正文开头，无前字符</li>
+	 *     <li>字段分隔符，即上个字段结束</li>
+	 *     <li>换行符，即新行开始</li>
+	 * </ul>
+	 *
+	 * @param preChar 前字符
+	 * @return 是否字段开始
+	 */
+	private boolean isFieldBegin(final int preChar) {
+		return preChar == -1
+			|| preChar == config.fieldSeparator
+			|| preChar == CharUtil.LF
+			|| preChar == CharUtil.CR;
+	}
+}

hutool-poi/src/main/java/org/dromara/hutool/poi/csv/CsvTokener.java

@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2024 Hutool Team and hutool.cn
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.dromara.hutool.poi.csv;
+
+import org.dromara.hutool.core.io.IORuntimeException;
+import org.dromara.hutool.core.io.IoUtil;
+import org.dromara.hutool.core.lang.wrapper.SimpleWrapper;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.io.Reader;
+
+public class CsvTokener extends SimpleWrapper<Reader> implements Closeable {
+
+	/**
+	 * 在Reader的位置（解析到第几个字符）
+	 */
+	private long index;
+	/**
+	 * 前一个字符
+	 */
+	private int prev;
+	/**
+	 * 是否使用前一个字符
+	 */
+	private boolean usePrev;
+
+	/**
+	 * 构造
+	 *
+	 * @param reader {@link Reader}
+	 */
+	public CsvTokener(final Reader reader) {
+		super(reader);
+	}
+
+	/**
+	 * 读取下一个字符，并记录位置
+	 *
+	 * @return 下一个字符
+	 */
+	public int next() {
+		if(this.usePrev){
+			this.usePrev = false;
+			return this.prev;
+		}
+		try {
+			this.prev = this.raw.read();
+		} catch (final IOException e) {
+			throw new IORuntimeException(e);
+		}
+		this.index++;
+		return this.prev;
+	}
+
+	/**
+	 * 将标记回退到第一个字符
+	 *
+	 * @throws IllegalStateException 当多次调用back时，抛出此异常
+	 */
+	public void back() throws IllegalStateException {
+		if (this.usePrev || this.index <= 0) {
+			throw new IllegalStateException("Stepping back two steps is not supported");
+		}
+		this.index --;
+		this.usePrev = true;
+	}
+
+	@Override
+	public void close() throws IOException {
+		IoUtil.nullSafeClose(this.raw);
+	}
+}

hutool-poi/src/test/java/org/dromara/hutool/poi/csv/CsvParserTest.java

@@ -29,7 +29,7 @@ public class CsvParserTest {
 	@Test
 	public void parseTest1() {
 		final StringReader reader = StrUtil.getReader("aaa,b\"bba\",ccc");
-		final CsvParser parser = new CsvParser(reader, null);
+		final CsvParser2 parser = new CsvParser2(reader, null);
 		final CsvRow row = parser.nextRow();
 		//noinspection ConstantConditions
 		Assertions.assertEquals("b\"bba\"", row.getRaw().get(1));
@@ -39,7 +39,7 @@ public class CsvParserTest {
 	@Test
 	public void parseTest2() {
 		final StringReader reader = StrUtil.getReader("aaa,\"bba\"bbb,ccc");
-		final CsvParser parser = new CsvParser(reader, null);
+		final CsvParser2 parser = new CsvParser2(reader, null);
 		final CsvRow row = parser.nextRow();
 		//noinspection ConstantConditions
 		Assertions.assertEquals("\"bba\"bbb", row.getRaw().get(1));
@@ -49,7 +49,7 @@ public class CsvParserTest {
 	@Test
 	public void parseTest3() {
 		final StringReader reader = StrUtil.getReader("aaa,\"bba\",ccc");
-		final CsvParser parser = new CsvParser(reader, null);
+		final CsvParser2 parser = new CsvParser2(reader, null);
 		final CsvRow row = parser.nextRow();
 		//noinspection ConstantConditions
 		Assertions.assertEquals("bba", row.getRaw().get(1));
@@ -59,7 +59,7 @@ public class CsvParserTest {
 	@Test
 	public void parseTest4() {
 		final StringReader reader = StrUtil.getReader("aaa,\"\",ccc");
-		final CsvParser parser = new CsvParser(reader, null);
+		final CsvParser2 parser = new CsvParser2(reader, null);
 		final CsvRow row = parser.nextRow();
 		//noinspection ConstantConditions
 		Assertions.assertEquals("", row.getRaw().get(1));