简单读取CSV文件的工具
参考：https://github.com/vegaasen/knowit-julekalender
package com.nstc.aims.controller.business.recordmould;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.Closeable;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.net.JarURLConnection;
import java.net.URL;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import com.nstc.aims.model.RecordMap;
/**
*
* Title: CsvUtils.java
*
* Description: *用于读取分隔符分隔文件的简单工具。默认分隔符为逗号。
*
* Company: 北京九恒星科技股份有限公司
*
* @author luhao copy from https://github.com/vegaasen/csv-importer-utils
*
* @since：2019年6月13日 下午1:19:22
*
*/
public final class CsvUtils {
/** 默认分隔字符 */
public static final char DEFAULT_DELIMITER = ',';
/** 默认编码集 */
public static final Charset DEFAULT_CHARSET = Charset.defaultCharset();
/** 空字符串 */
private static final String EMPTY = "";
/** 单引号字符 */
private static final char HYPHEN = '"';
/** 占位字符 */
private static final char PLACEHOLDER = '\u02B0';
/** 占位字符串 */
private static final String PLACEHOLDER_STR = String.valueOf(PLACEHOLDER);
/** 分隔符 */
private static String delimiter = String.valueOf(DEFAULT_DELIMITER);
/** 分隔符字符 */
private static char delimiter_char = DEFAULT_DELIMITER;
/** 编码集 */
private static Charset charset = DEFAULT_CHARSET;
/** 是否忽略第一行 */
private static boolean omitFirstLine = false;
private CsvUtils() {
}
/** 获得表格元素 */
public static Map> getElementsFromCsv(final String location) throws FileNotFoundException {
return getElementsFromCsv(location, false);
}
/**
* @param location The location
* @param mapTitles true == map attributes to the titles (if any) found on the top level of the csv.
* @return a map containing the line, and its mapping wihting that line. Simple.
* @throws FileNotFoundException _
*/
public static Map> getElementsFromCsv(final String location, final boolean mapTitles) throws FileNotFoundException {
if (!"".equals(location)) {
try {
return getElementsFromCsv(FileUtils.getFile(location), mapTitles);
} catch (IOException e) {
throw new FileNotFoundException("File not found.");
}
}
throw new IllegalArgumentException("Missing argument.");
}
public static Map> getElementsFromCsv(final File file) {
return getElementsFromCsv(file, false);
}
/**
* @param file The file
* @param mapTitles true == map attributes to the titles (if any) found on the top level of the csv.
* @return a map containing the line, and its mapping wihting that line. Simple.
*/
public static Map> getElementsFromCsv(final File file, final boolean mapTitles) {
if (file != null) {
try {
return readCsv(FileUtils.getBufferedReader(file), mapTitles);
} catch (IOException e) {
e.printStackTrace();
}
}
throw new IllegalArgumentException("Missing argument.");
}
private static Map> readCsv(BufferedReader input, final boolean mapTitles) throws IOException {
if (input != null && input.ready()) {
Map> entries = new TreeMap>();
List titles = new ArrayList();
String currentLine;
boolean completedFirstLine = false/*, omitted = false*/;
int counter = 0, position = 0;
while ((currentLine = input.readLine()) != null) {
if (!"".equals(currentLine)) {
currentLine = massageLine(currentLine);
if (mapTitles) {
if (!completedFirstLine) {
if (currentLine.contains(delimiter)) {
Collections.addAll(titles, currentLine.split(delimiter));
} else {
throw new RuntimeException(
String.format("Unable to find {%s} as delimiter. Wrong delimiter?", delimiter)
);
}
completedFirstLine = true;
}
}
final Map entryLine = new TreeMap();
if (omitFirstLine) {
omitFirstLine = false;
continue;
}
for (String entry : currentLine.split(delimiter)) {
if (entry.contains(PLACEHOLDER_STR)) {
entry = entry.replaceAll(PLACEHOLDER_STR, delimiter);
}
entryLine.put(
((mapTitles) ? titles.get(position) : String.valueOf(position)),
((charset != DEFAULT_CHARSET) ? new String(entry.getBytes(), charset) : entry)
);
position++;
}
entries.put(counter, entryLine);
position = 0;
counter++;
}
}
return entries;
}
return Collections.emptyMap();
}
private static String massageLine(final String line) {
if (!"".equals(line)) {
if (line.contains("\"")) {
ArrayList modifiedLine = new ArrayList();
boolean withinHyphenSequence = false;
for (int i = 0; i < line.length(); i++) {
if (line.charAt(i) == HYPHEN) {
withinHyphenSequence = ((!withinHyphenSequence));
}
if (withinHyphenSequence) {
if (line.charAt(i) == delimiter_char) {
modifiedLine.add(PLACEHOLDER);
} else {
modifiedLine.add(line.charAt(i));
}
} else {
modifiedLine.add(line.charAt(i));
}
}
return getStringFromList(modifiedLine);
}
return line;
}
return EMPTY;
}
private static String getStringFromList(ArrayList list) {
StringBuilder sb = new StringBuilder();
for (char s : list) {
sb.append(s);
}
return sb.toString();
}
public static void setDelimiter(final String del) {
if (!"".equals(del)) {
delimiter = del;
delimiter_char = del.charAt(0);
}
}
public static void setCharset(final Charset chSet) {
charset = chSet;
}
public static void setOmitFirstLine(final boolean choice) {
omitFirstLine = choice;
}
/**
*
* @Description:组装Excel中的标题行
* @param fileName 文件路径
* @param sheetId sheet页，从0开始
* @param beginRow 始读行，从0开始
* @param beginCol 始读列，从0开始
* @return List
* @author luhao
* @since：2019年6月13日 下午2:48:01
*/
public static List getRecordMapFromCsv(String fileInput, int sheetId, int beginRow, int beginCol) {
List result = new ArrayList();
try {
Map> elementsFromCsv = getElementsFromCsv(fileInput,false);
Map line = elementsFromCsv.get(beginRow);
int cols = line.size();
for (int i = beginCol; i < cols && beginCol < cols; i++) {
RecordMap recordMap = new RecordMap();
recordMap.setColName(line.get(String.valueOf(i)));
recordMap.setColIndex(i);
result.add(recordMap);
}
} catch (FileNotFoundException e) {
throw new RuntimeException(e.getMessage());
}
return result;
}
}
final class FileUtils {
private static final int DEFAULT_BUFFER_SIZE = 65536;
private static int bufferSize = DEFAULT_BUFFER_SIZE;
public static File getFileFromClassPath(final String fileName) {
if (!"".equals(fileName)) {
final URL url = FileUtils.class.getResource(fileName);
if (url != null) {
String resource = null;
try {
if("file".equals(url.getProtocol())) {
resource = url.getFile();
}else if("jar".equals(url.getProtocol())) {
JarURLConnection connection = (JarURLConnection) url.openConnection();
resource = connection.getJarFile().getName();
}
return new File(resource);
} catch (Exception e) {
//eating the error..
}
}
return null;
}
throw new IllegalArgumentException("Missing argument fileName.");
}
public static File getFile(final String filename) throws FileNotFoundException {
if (!"".equals(filename)) {
final File file = new File(filename);
if (file.exists()) {
return file;
}
throw new FileNotFoundException(String.format("Unable to find file %s", filename));
}
throw new IllegalArgumentException("Missing argument fileName.");
}
public static BufferedReader getBufferedReader(final File file) throws FileNotFoundException {
if (file != null) {
return new BufferedReader(new FileReader(file));
}
throw new IllegalArgumentException("Missing argument");
}
public static BufferedInputStream readStreamFromFile(final File file) throws IOException {
//final int size = (int) file.length();
try {
return new BufferedInputStream(new FileInputStream(file), bufferSize);
} catch (final FileNotFoundException e) {
throw new IOException("File not found");
}
}
public static BufferedInputStream readStreamFromFile(final String filename) throws IOException {
final File file = new File(filename);
return readStreamFromFile(file);
}
public static byte[] readBytesFromFile(final String filename) throws IOException {
final File file = new File(filename);
final int size = (int) file.length();
final byte[] buff = new byte[size];
InputStream in = null;
try {
in = new BufferedInputStream(new FileInputStream(file), bufferSize);
in.read(buff, 0, size);
return buff;
} catch (final FileNotFoundException e) {
throw new IOException("File `" + filename + "' not found");
} catch (final IOException e) {
throw new IOException("Error writing file `" + filename + "'", e);
} finally {
closeSilently(in);
}
}
public static void closeSilently(final Closeable closeable) {
if (closeable == null) {
return;
}
try {
closeable.close();
} catch (final IOException e) {
//
}
}
}
测试类
public static void main(String... args) {
try {
CsvUtils.setDelimiter(",");
CsvUtils.setCharset(Charset.forName("GBK"));
Map> csvElements = CsvUtils
.getElementsFromCsv("C:/Users/Administrator/Desktop/_aaa.csv", false);
System.out.println(csvElements);
} catch (FileNotFoundException e) {
System.exit(-1);
}
System.exit(1);
}