FileReader fr = new FileReader(inp);
CSVReader reader = new CSVReader(fr, ',', '"');
// writer
File writtenFromWhile = new File(dliRootPath + writtenFromWhilePath);
writtenFromWhile.createNewFile();
CSVWriter writeFromWhile = new CSVWriter(new FileWriter(writtenFromWhile), ',', '"');
int insideWhile = 0;
String[] currRow = null;
while ((currRow = reader.readNext()) != null) {
insideWhile++;
writeFromWhile.writeNext(currRow);
}
System.out.println("inside While: " + insideWhile);
System.out.println("lines read (acc.to CSV reader): " + reader.getLinesRead());
输出结果为：
inside While: 162199
lines read (acc.to CSV reader): 256865
即使所有行都写入输出CSV（在文本编辑器中查看时，Excel显示的行数少得多），while循环的迭代次数与输入CSV中的行次数不同。我的主要目标是在每行的while循环中实现一些其他逻辑。 我一直试图调试两天（更大的代码）没有任何结果。
请解释我如何循环while 256865次
参考数据，完整图片：
Here是我在上面的代码段中阅读的CSV。
我的完整程序尝试根据字段标题和作者（即如果作者和标题在2条记录中是相同的，甚至是this CSV中不存在的那些记录来分离this CSV如果其他字段不同，则将它们视为重复，不应写入输出文件）。这是我的完整代码（差异应该在300000左右，但我的代码输出文件只有~210000）：
//TODO ask id
/*(*
* id also there in fields getting matched (thisRow[0] is id)
* u can replace it by thisRow[fielAnd Column.get(0)] to eliminate id
*/
package mainOne;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import com.opencsv.CSVReader;
import com.opencsv.CSVWriter;
public class Diff_V3 {
static String dliRootPath = "/home/gurnoor/Incoming/Untitled Folder 2/";
static String dli = "new-dli-IITG.csv";
static String oldDli = "dli-iisc.csv";
static String newFile = "newSampleFile.csv";// not used
static String unqFile = "UniqueFileFinal.csv";
static String log = "Diff_V3_log.txt";
static String splittedNewDliDir = "/home/gurnoor/Incoming/Untitled Folder 2/splitted new file";
static String splittedOldDliDir = "/home/gurnoor/Incoming/Untitled Folder 2/splitted old file";
// debug
static String testFilePath = "testFile.csv";
static int insidepopulateMapFromSplittedCSV = 0;
public static void main(String[] args) throws IOException, CustomException {
// _readSample(dliRootPath+dli, dliRootPath+newFile);
// System.out.println(areIDsunique(dliRootPath + dli, 550841) );// open
// in geany to get total no
// of lines
// TODO implement sparate function to check equals
// File filteredFile = new File(dliRootPath + "filteredFile.csv");
// filteredFile.createNewFile();
File logFile = new File(dliRootPath + log);
logFile.createNewFile();
new File(dliRootPath + testFilePath).createNewFile();
List<String> fieldsToBeMatched = new ArrayList<>();
fieldsToBeMatched.add("dc.contributor.author[]");
fieldsToBeMatched.add("dc.title[]");
filterUniqueFileds(new File(splittedNewDliDir), new File(splittedOldDliDir), fieldsToBeMatched);
}
/**
* NOTE: might remove the row where fieldToBeMatched is null
*
* @param inpfile
* @param file
* @param filteredFile
* @param fieldsToBeMatched
* @throws IOException
* @throws CustomException
*/
private static void filterUniqueFileds(File newDir, File oldDir, List<String> fieldsToBeMatched)
throws IOException, CustomException {
CSVReader reader = new CSVReader(new FileReader(new File(dliRootPath + dli)), '|');
// writer
File unqFileOp = new File(dliRootPath + unqFile);
unqFileOp.createNewFile();
CSVWriter writer = new CSVWriter(new FileWriter(unqFileOp), '|');
// logWriter
BufferedWriter logWriter = new BufferedWriter(new FileWriter(new File(dliRootPath + log)));
String[] headingRow = // allRows.get(0);
reader.readNext();
writer.writeNext(headingRow);
int headingLen = headingRow.length;
// old List
System.out.println("[INFO] reading old list...");
// CSVReader oldReader = new CSVReader(new FileReader(new
// File(dliRootPath + oldDli)));
Map<String, List<String>> oldMap = new HashMap<>();
oldMap = populateMapFromSplittedCSV(oldMap, oldDir);// populateMapFromCSV(oldMap,
// oldReader);
// oldReader.close();
System.out.println("[INFO] Read old List. Size = " + oldMap.size());
printMapToCSV(oldMap, dliRootPath + testFilePath);
// map of fieldName, ColumnNo
Map<String, Integer> fieldAndColumnNoInNew = new HashMap<>(getColumnNo(fieldsToBeMatched, headingRow));
Map<String, Integer> fieldAndColumnNoInOld = new HashMap<>(
getColumnNo(fieldsToBeMatched, (String[]) oldMap.get("id").toArray()));
// error check: did columnNo get populated?
if (fieldAndColumnNoInNew.isEmpty()) {
reader.close();
writer.close();
throw new CustomException("field to be matched not present in input CSV");
}
// TODO implement own array compare using areEqual()
// error check
// if( !Arrays.equals(headingRow, (String[]) oldMap.get("id").toArray())
// ){
// System.out.println("heading in new file, old file: \n"+
// Arrays.toString(headingRow));
// System.out.println(Arrays.toString((String[])
// oldMap.get("id").toArray()));
// reader.close();
// writer.close();
// oldReader.close();
// throw new CustomException("Heading rows are not same in old and new
// file");
// }
int noOfRecordsInOldList = 0, noOfRecordsWritten = 0, checkManually = 0;
String[] thisRow;
while ((thisRow = reader.readNext()) != null) {
// for(int l=allRows.size()-1; l>=0; l--){
// thisRow=allRows.get(l);
// error check
if (thisRow.length != headingLen) {
String error = "Line no: " + reader.getLinesRead() + " in file: " + dliRootPath + dli
+ " not read. Check manually";
System.err.println(error);
logWriter.append(error + "\n");
logWriter.flush();
checkManually++;
continue;
}
// write if not present in oldMap
if (!oldMap.containsKey(thisRow[0])) {
writer.writeNext(thisRow);
writer.flush();
noOfRecordsWritten++;
} else {
// check if all reqd fields match
List<String> twinRow = oldMap.get(thisRow[0]);
boolean writtenToOp = false;
// for (int k = 0; k < fieldsToBeMatched.size(); k++) {
List<String> newFields = new ArrayList<>(fieldAndColumnNoInNew.keySet());
List<String> oldFields = new ArrayList<>(fieldAndColumnNoInOld.keySet());
// faaltu error check
if (newFields.size() != oldFields.size()) {
reader.close();
writer.close();
CustomException up = new CustomException("something is really wrong");
throw up;
}
// for(String fieldName : fieldAndColumnNoInNew.keySet()){
for (int m = 0; m < newFields.size(); m++) {
int columnInNew = fieldAndColumnNoInNew.get(newFields.get(m)).intValue();
int columnInOld = fieldAndColumnNoInOld.get(oldFields.get(m)).intValue();
String currFieldTwin = twinRow.get(columnInOld);
String currField = thisRow[columnInNew];
if (!areEqual(currField, currFieldTwin)) {
writer.writeNext(thisRow);
writer.flush();
writtenToOp = true;
noOfRecordsWritten++;
System.out.println(noOfRecordsWritten);
break;
}
}
if (!writtenToOp) {
noOfRecordsInOldList++;
// System.out.println("[INFO] present in old List: \n" +
// Arrays.toString(thisRow) + " AND\n"
// + twinRow.toString());
}
}
}
System.out.println("--------------------------------------------------------\nDebug info");
System.out.println("old File: " + oldMap.size());
System.out.println("new File:" + reader.getLinesRead());
System.out.println("no of records in old list (present in both old and new) = " + noOfRecordsInOldList);
System.out.println("checkManually: " + checkManually);
System.out.println("noOfRecordsInOldList+checkManually = " + (noOfRecordsInOldList + checkManually));
System.out.println("no of records written = " + noOfRecordsWritten);
System.out.println();
System.out.println("inside populateMapFromSplittedCSV() " + insidepopulateMapFromSplittedCSV + "times");
logWriter.close();
reader.close();
writer.close();
}
private static void printMapToCSV(Map<String, List<String>> oldMap, String testFilePath2) throws IOException {
// writer
int i = 0;
CSVWriter writer = new CSVWriter(new FileWriter(new File(testFilePath2)), '|');
for (String key : oldMap.keySet()) {
List<String> row = oldMap.get(key);
String[] tempRow = new String[row.size()];
tempRow = row.toArray(tempRow);
writer.writeNext(tempRow);
writer.flush();
i++;
}
writer.close();
System.out.println("[hello from line 210 ( inside printMapToCSV() ) of ur code] wrote " + i + " lines");
}
private static Map<String, List<String>> populateMapFromSplittedCSV(Map<String, List<String>> oldMap, File oldDir)
throws IOException {
File defective = new File(dliRootPath + "defectiveOldFiles.csv");
defective.createNewFile();
CSVWriter defectWriter = new CSVWriter(new FileWriter(defective));
CSVReader reader = null;
for (File oldFile : oldDir.listFiles()) {
insidepopulateMapFromSplittedCSV++;
reader = new CSVReader(new FileReader(oldFile), ',', '"');
oldMap = populateMapFromCSV(oldMap, reader, defectWriter);
// printMapToCSV(oldMap, dliRootPath+testFilePath);
System.out.println(oldMap.size());
reader.close();
}
defectWriter.close();
System.out.println("inside populateMapFromSplittedCSV() " + insidepopulateMapFromSplittedCSV + "times");
return new HashMap<String, List<String>>(oldMap);
}
private static Map<String, Integer> getColumnNo(List<String> fieldsToBeMatched, String[] headingRow) {
Map<String, Integer> fieldAndColumnNo = new HashMap<>();
for (String field : fieldsToBeMatched) {
for (int i = 0; i < headingRow.length; i++) {
String heading = headingRow[i];
if (areEqual(field, heading)) {
fieldAndColumnNo.put(field, Integer.valueOf(i));
break;
}
}
}
return fieldAndColumnNo;
}
private static Map<String, List<String>> populateMapFromCSV(Map<String, List<String>> oldMap, CSVReader oldReader,
CSVWriter defectWriter) throws IOException {
int headingLen = 0;
List<String> headingRow = null;
if (oldReader.getLinesRead() > 1) {
headingRow = oldMap.get("id");
headingLen = headingRow.size();
}
String[] thisRow;
int insideWhile = 0, addedInMap = 0, doesNotContainKey = 0, containsKey = 0;
while ((thisRow = oldReader.readNext()) != null) {
// error check
// if (oldReader.getLinesRead() > 1) {
// if (thisRow.length != headingLen) {
// System.err.println("Line no: " + oldReader.getLinesRead() + " in
// file: " + dliRootPath + oldDli
// + " not read. Check manually");
// defectWriter.writeNext(thisRow);
// defectWriter.flush();
// continue;
// }
// }
insideWhile++;
if (!oldMap.containsKey(thisRow[0])) {
doesNotContainKey++;
List<String> fullRow = Arrays.asList(thisRow);
fullRow = oldMap.put(thisRow[0], fullRow);
if (fullRow == null) {
addedInMap++;
}
} else {
List<String> twinRow = oldMap.get(thisRow[0]);
boolean writtenToOp = false;
// for(String fieldName : fieldAndColumnNoInNew.keySet()){
for (int m = 0; m < headingRow.size(); m++) {
String currFieldTwin = twinRow.get(m);
String currField = thisRow[m];
if (!areEqual(currField, currFieldTwin)) {
System.err.println("do something!!!!!! DUPLICATE ID in old file");
containsKey++;
FileWriter logWriter = new FileWriter(new File((dliRootPath + log)));
System.err.println("[Skipped record] in old file. Row no: " + oldReader.getLinesRead()
+ "\nRecord: " + Arrays.toString(thisRow));
logWriter.append("[Skipped record] in old file. Row no: " + oldReader.getLinesRead()
+ "\nRecord: " + Arrays.toString(thisRow));
logWriter.close();
break;
}
}
}
}
System.out.println("inside while: " + insideWhile);
System.out.println("oldMap size = " + oldMap.size());
System.out.println("addedInMap: " + addedInMap);
System.out.println("doesNotContainKey: " + doesNotContainKey);
System.out.println("containsKey: " + containsKey);
return new HashMap<String, List<String>>(oldMap);
}
private static boolean areEqual(String field, String heading) {
// TODO implement, askSubhayan
return field.trim().equals(heading.trim());
}
/**
* Returns the first duplicate ID OR the string "unique" OR (rarely)
* totalLinesInCSV != totaluniqueIDs
*
* @param inpCSV
* @param totalLinesInCSV
* @return
* @throws IOException
*/
private static String areIDsunique(String inpCSV, int totalLinesInCSV) throws IOException {
CSVReader reader = new CSVReader(new FileReader(new File(dliRootPath + dli)), '|');
List<String[]> allRows = new ArrayList<>(reader.readAll());
reader.close();
Set<String> id = new HashSet<>();
for (String[] thisRow : allRows) {
if (thisRow[0] != null || !thisRow[0].isEmpty() || id.add(thisRow[0])) {
return thisRow[0];
}
}
if (id.size() == totalLinesInCSV) {
return "unique";
} else {
return "totalLinesInCSV != totaluniqueIDs";
}
}
/**
* writes 20 rowsof input csv into the output file
*
* @param input
* @param output
* @throws IOException
*/
public static void _readSample(String input, String output) throws IOException {
File opFile = new File(dliRootPath + newFile);
opFile.createNewFile();
CSVWriter writer = new CSVWriter(new FileWriter(opFile));
CSVReader reader = new CSVReader(new FileReader(new File(dliRootPath + dli)), '|');
for (int i = 0; i < 20; i++) {
// String[] op;
// for(String temp: reader.readNext()){
writer.writeNext(reader.readNext());
// }
// System.out.println();
}
reader.close();
writer.flush();
writer.close();
}
}
答案 0 :(得分：0)
CSV单元格内未转义的引号可能会弄乱您的整个数据。如果您手动创建了正在使用的数据，则可能会在CSV中发生这种情况。下面是我为这种情况写了一段时间的函数。如果这不是分享它的正确位置，请告诉我。
/**
* removes quotes inside a cell/column puts curated data in
* "../CuratedFiles"
*
* @param curateDir
* @param del Csv column delimiter
* @throws IOException
*/
public static void curateCsvRowQuotes(File curateDir, String del) throws IOException {
File parent = curateDir.getParentFile();
File curatedDir = new File(parent.getAbsolutePath() + "/CuratedFiles");
curatedDir.mkdir();
for (File file : curateDir.listFiles()) {
BufferedReader bufRead = new BufferedReader(new FileReader(file));
// output
File fOp = new File(curatedDir.getAbsolutePath() + "/" + file.getName());
fOp.createNewFile();
BufferedWriter bufW = new BufferedWriter(new FileWriter(fOp));
bufW.append(bufRead.readLine() + "\n");// heading
// logs
File logFile = new File(curatedDir.getAbsolutePath() + "/CurationLogs.txt");
logFile.createNewFile();
BufferedWriter logWriter = new BufferedWriter(new FileWriter(logFile));
String thisLine = null;
int lineCount = 0;
while ((thisLine = bufRead.readLine()) != null) {
String opLine = "";
int endIndex = thisLine.indexOf("\"" + del);
String str = thisLine.substring(0, endIndex);
opLine += str + "\"" + del;
while (endIndex != (-1)) {
// leave out first " in a cell
int tempIndex = thisLine.indexOf("\"" + del, endIndex + 2);
if (tempIndex == (-1)) {
break;
}
str = thisLine.substring(endIndex + 2, tempIndex);
int indexOfQuote = str.indexOf("\"");
opLine += str.substring(0, indexOfQuote + 1);
// remove all "
str = str.substring(indexOfQuote + 1);
str = str.replace("\"", "");
opLine += str + "\"" + del;
endIndex = thisLine.indexOf("\"" + del, endIndex + 2);
}
str = thisLine.substring(thisLine.lastIndexOf("\"" + del) + 2);
if ((str != null) && str.matches("[" + del + "]+")) {
opLine += str;
}
System.out.println(opLine);
bufW.append(opLine + "\n");
bufW.flush();
lineCount++;
}
System.out.println(lineCount + " no of lines in " + file.getName());
bufRead.close();
bufW.close();
}
}
答案 1 :(得分：0)
就我而言，我在readNext（）之前使用过csvReader.readAll（）。
喜欢
Opcodes.Ldobj所以我的csvReader.readNext（）返回null。由于myData已经读取了所有值。
请注意使用readNext（）和readAll（）函数。