Java之CSV文件转List数据工具
借鉴博客：https://www.cnblogs.com/yybinger/p/11907193.html
工具文件，可直接调用，亲测有效：
package com.powersi.biz.park.network.util; import java.io.*; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; /** * @Description TODO * @Author zhouruntao * @Date 2020/11/11 11:18 */ public class CsvToListUtil { /** * CSV文件编码 */ private static final String ENCODE = "UTF-8"; /** * 读取CSV文件得到List，默认使用UTF-8编码 * @param fileName 文件路径 * @return */ public static List<String> getLines(String fileName) { return getLines(fileName, ENCODE); } /** * 读取CSV文件得到List * @param fileName 文件路径 * @param encode 编码 * @return */ public static List<String> getLines(String fileName, String encode) { List<String> lines = new ArrayList<String>(); BufferedReader br = null; InputStreamReader isr = null; FileInputStream fis = null; try { fis = new FileInputStream(fileName); isr = new InputStreamReader(fis, encode); br = new BufferedReader(isr); String line; while ((line = br.readLine()) != null) { StringBuilder sb = new StringBuilder(); sb.append(line); boolean readNext = countChar(sb.toString(), '"', 0) % 2 == 1; // 如果双引号是奇数的时候继续读取。考虑有换行的是情况 while (readNext) { line = br.readLine(); if (line == null) { return null; } sb.append(line); readNext = countChar(sb.toString(), '"', 0) % 2 == 1; } lines.add(sb.toString()); } } catch (Exception e) { // log.error("Read CSV file failure :{}", e); System.out.println("Read CSV file failure :{}" + e); } finally { try { if (br != null) { br.close(); } if (isr != null) { isr.close(); } if (fis != null) { fis.close(); } } catch (IOException e) { // log.error("Close stream failure :{}", e); System.out.println("Close stream failure :{}" + e); } } return lines; } public static List<String> getLines(File file, String encode) { List<String> lines = new ArrayList<String>(); BufferedReader br = null; InputStreamReader isr = null; FileInputStream fis = null; try { fis = new FileInputStream(file); isr = new InputStreamReader(fis, encode); br = new BufferedReader(isr); String line; while ((line = br.readLine()) != null) { StringBuilder sb = new StringBuilder(); sb.append(line); boolean readNext = countChar(sb.toString(), '"', 0) % 2 == 1; // 如果双引号是奇数的时候继续读取。考虑有换行的是情况 while (readNext) { line = br.readLine(); if (line == null) { return null; } sb.append(line); readNext = countChar(sb.toString(), '"', 0) % 2 == 1; } lines.add(sb.toString()); } } catch (Exception e) { // log.error("Read CSV file failure :{}", e); System.out.println("Read CSV file failure :{}" + e); } finally { try { if (br != null) { br.close(); } if (isr != null) { isr.close(); } if (fis != null) { fis.close(); } } catch (IOException e) { // log.error("Close stream failure :{}", e); System.out.println("Close stream failure :{}" + e); } } return lines; } public static String[] fromCSVLine(String source) { return fromCSVLine(source, 0); } /** * 把CSV文件的一行转换成字符串数组。指定数组长度，不够长度的部分设置为null * @param source * @param size * @return */ public static String[] fromCSVLine(String source, int size) { List list = fromCSVLineToArray(source); if (size < list.size()) { size = list.size(); } String[] arr = new String[size]; list.toArray(arr); return arr; } public static List fromCSVLineToArray(String source) { if (source == null || source.length() == 0) { return new ArrayList(); } int currentPosition = 0; int maxPosition = source.length(); int nextComa = 0; List list = new ArrayList(); while (currentPosition < maxPosition) { nextComa = nextComma(source, currentPosition); list.add(nextToken(source, currentPosition, nextComa)); currentPosition = nextComa + 1; if (currentPosition == maxPosition) { list.add(""); } } return list; } /** * 把字符串类型的数组转换成一个CSV行。（输出CSV文件的时候用） * * @param arr * @return */ public static String toCSVLine(String[] arr) { if (arr == null) { return ""; } StringBuilder sb = new StringBuilder(); for (int i = 0; i < arr.length; i++) { String item = addQuote(arr[i]); sb.append(item); if (arr.length - 1 != i) { sb.append(","); } } return sb.toString(); } /** * 将list的第一行作为Map的key，下面的列作为Map的value * @param list * @return */ public static List<Map<String, String>> parseList(List<String> list) { List<Map<String, String>> resultList = new ArrayList<Map<String, String>>(); String firstLine = list.get(0); String[] fields = firstLine.split(","); for (int i = 1; i < list.size(); i++) { String valueLine = list.get(i); String[] valueItems = CsvToListUtil.fromCSVLine(valueLine); Map<String, String> map = new HashMap<String, String>(); for (int j = 0; j < fields.length; j++) { map.put(fields[j], valueItems[j]); } resultList.add(map); } return resultList; } /** * 字符串类型的List转换成一个CSV行。（输出CSV文件的时候用） * * @param strArrList * @return */ public static String toCSVLine(ArrayList strArrList) { if (strArrList == null) { return ""; } String[] strArray = new String[strArrList.size()]; for (int idx = 0; idx < strArrList.size(); idx++) { strArray[idx] = (String) strArrList.get(idx); } return toCSVLine(strArray); } /** * 计算指定字符的个数 * * @param str 文字列 * @param c 字符 * @param start 开始位置 * @return 个数 */ private static int countChar(String str, char c, int start) { int index = str.indexOf(c, start); return index == -1 ? 0 : countChar(str, c, index + 1) + 1; } /** * 查询下一个逗号的位置。 * * @param source 文字列 * @param st 检索开始位置 * @return 下一个逗号的位置。 */ private static int nextComma(String source, int st) { int maxPosition = source.length(); boolean inquote = false; while (st < maxPosition) { char ch = source.charAt(st); if (!inquote && ch == ',') { break; } else if ('"' == ch) { inquote = !inquote; } st++; } return st; } /** * 取得下一个字符串 * * @param source * @param st * @param nextComma * @return */ private static String nextToken(String source, int st, int nextComma) { StringBuilder strb = new StringBuilder(); int next = st; while (next < nextComma) { char ch = source.charAt(next++); if (ch == '"') { if ((st + 1 < next && next < nextComma) && (source.charAt(next) == '"')) { strb.append(ch); next++; } } else { strb.append(ch); } } return strb.toString(); } /** * 在字符串的外侧加双引号。如果该字符串的内部有双引号的话，把"转换成""。 * * @param item 字符串 * @return 处理过的字符串 */ private static String addQuote(String item) { if (item == null || item.length() == 0) { return "\"\""; } StringBuilder sb = new StringBuilder(); sb.append('"'); for (int idx = 0; idx < item.length(); idx++) { char ch = item.charAt(idx); if ('"' == ch) { sb.append("\"\""); } else { sb.append(ch); } } sb.append('"'); return sb.toString(); } }
我的调用（我重写了getLines方法，因为我这里要传file文件，而不是传文件路径）：
//调用CSV文件转List工具 List<String> lines = CsvToListUtil.getLines(file, "GBK"); List<Map<String, String>> mapList = CsvToListUtil.parseList(lines); System.out.println(Arrays.toString(mapList.toArray()));
。。。
