Java CsvWriter类代码示例

import com.univocity.parsers.csv.CsvWriter; //导入依赖的package包/类
@Test
public void testMapWithUnexpectedHeaders() {
	OutputValueSwitch writerSwitch = new OutputValueSwitch("type");
	writerSwitch.addSwitchForValue("SUPER", new ObjectRowWriterProcessor(), "type", "h1", "h2", "h3", "h4");
	writerSwitch.addSwitchForValue("DUPER", new ObjectRowWriterProcessor(), "type", "h4", "Z1", "Z3", "h1");

	CsvWriterSettings settings = new CsvWriterSettings();
	settings.setExpandIncompleteRows(true);
	settings.getFormat().setLineSeparator("\n");
	settings.setHeaderWritingEnabled(false);
	settings.setRowWriterProcessor(writerSwitch);

	StringWriter output = new StringWriter();
	CsvWriter writer = new CsvWriter(output, settings);

	writer.writeRow(newMap("SUPER", "Z1=>v1;h2=>v2;h3=>v3;h4=>v4"));
	writer.writeRow(newMap("DUPER", "Z1=>v1;h2=>v2;Z3=>v3;h4=>v4"));
	writer.close();

	assertEquals(output.toString(), "" +
			"SUPER,,v2,v3,v4\n" +
			"DUPER,v4,v1,v3,\n");
}
 

import com.univocity.parsers.csv.CsvWriter; //导入依赖的package包/类
@Test
public void testAppendAndExpandWhenAppendingChar() {
	CsvWriterSettings settings = new CsvWriterSettings();
	settings.getFormat().setLineSeparator("\n");
	settings.getFormat().setDelimiter('\t');
	settings.setMaxCharsPerColumn(16); // note default max length before expanding
	settings.getFormat().setQuote('"');
	settings.getFormat().setQuoteEscape('"');
	settings.setIgnoreLeadingWhitespaces(false);
	settings.setIgnoreTrailingWhitespaces(false);
	settings.setQuoteAllFields(true);
	settings.setEmptyValue("");

	StringWriter stringWriter = new StringWriter();
	CsvWriter writer = new CsvWriter(stringWriter, settings);

	// test data's first column length is specific to repro bug occuring due to
	// appending quote character occuring at writer buffer boundary
	String[] testCase = {"abcdefghijklmno", "pqrst", "uvwxyz"};
	String expectedString = "\"abcdefghijklmno\"\t\"pqrst\"\t\"uvwxyz\"\n";

	writer.writeRow(testCase);
	writer.close();

	assertEquals(stringWriter.toString(), expectedString);
}
 

import com.univocity.parsers.csv.CsvWriter; //导入依赖的package包/类
@Test
public void testRowExpansion() {
	StringWriter output = new StringWriter();

	CsvWriterSettings settings = new CsvWriterSettings();
	settings.setExpandIncompleteRows(true);
	settings.getFormat().setLineSeparator("\n");
	settings.setHeaderWritingEnabled(true);
	settings.setHeaders("A", "B", "C", "D", "E", "F");

	CsvWriter writer = new CsvWriter(output, settings);
	writer.writeRow();
	writer.writeRow("V1", "V2", "V3");
	writer.writeRow("V1", "V2", "V3", 4, 5);
	writer.writeRow("V1", "V2", "V3", 4, 5, 6);

	writer.close();

	assertEquals(output.toString(), "A,B,C,D,E,F\n,,,,,\nV1,V2,V3,,,\nV1,V2,V3,4,5,\nV1,V2,V3,4,5,6\n");
}
 

import com.univocity.parsers.csv.CsvWriter; //导入依赖的package包/类
public void writeBlocks(List<BlockWithData> blocks, String pathToFile) {
    CsvWriter csvWriter = dataParser.preparOutputFile(pathToFile);
    if (csvWriter != null) {
        // Write the record headers of this file
        List<String> fieldsNames = getBlockFieldsNames(blocks);
        fieldsNames.add("Probability");
        csvWriter.writeHeaders(fieldsNames);

        // Let's write the rows one by one
        for (BlockWithData block : blocks) {
            for (Record record : block.getMembers()) {
                for (String recordEntry : record.getEntries()) {
                    csvWriter.writeValue(recordEntry);
                }
                csvWriter.writeValues(block.getMemberProbability(record));
                csvWriter.writeValuesToRow();
            }
        }
        // Here we just tell the writer to write everything and close the given output Writer instance.
        csvWriter.close();
    }
}
 

import com.univocity.parsers.csv.CsvWriter; //导入依赖的package包/类
public void writeExperimentsMeasurements(IMeasurements measurements, File tempFile) throws SizeNotEqualException {
    CsvWriter csvWriter = dataParser.preparOutputFile(tempFile);
    csvWriter.writeHeaders(THRESHOLD, RANKED_VALUE, MRR, NORM_RANKED_VALUE, NORM_MRR, MILLER_RANKED_VALUE, MILLER_MRR_VALUE);

    List<Double> mrrValues = measurements.getMrrValuesSortedByThreshold();
    List<Double> rankedValues = measurements.getRankedValuesSortedByThreshold();
    List<Double> thresholds = measurements.getThresholdSorted();
    List<Double> normalizedRankedValues = measurements.getNormalizedRankedValuesSortedByThreshold();
    List<Double> normalizedMRRValues = measurements.getNormalizedMRRValuesSortedByThreshold();
    assertSize(measurements);

    Double millerRankedValue = getMillerRankedValue(rankedValues);
    Double millerMRRValue = getMillerMRRValue(mrrValues);
    for (int i = 1; i < thresholds.size(); i++) {
        csvWriter.writeValue(MRR, mrrValues.get(i));
        csvWriter.writeValue(THRESHOLD, thresholds.get(i));
        csvWriter.writeValue(RANKED_VALUE, rankedValues.get(i));
        csvWriter.writeValue(NORM_RANKED_VALUE, normalizedRankedValues.get(i));
        csvWriter.writeValue(NORM_MRR, normalizedMRRValues.get(i));
        csvWriter.writeValue(MILLER_RANKED_VALUE, millerRankedValue);
        csvWriter.writeValue(MILLER_MRR_VALUE, millerMRRValue);

        csvWriter.writeValuesToRow();
    }
    csvWriter.close();
}
 

import com.univocity.parsers.csv.CsvWriter; //导入依赖的package包/类
@Override
public String createString(int rowsToGenerate) {
    StringWriter stringWriter = new StringWriter();
    CsvWriter csvWriter = new CsvWriter(stringWriter, csvWriterSettings);
    writeValues(csvWriter, rowsToGenerate);
    return stringWriter.toString();
}
 

import com.univocity.parsers.csv.CsvWriter; //导入依赖的package包/类
private void writeValues(CsvWriter writer, int rowsToGenerate) {
    Records records = recordFactory.generateRecords(rowsToGenerate);
    if (settings.isIncludingHeaders()) {
        records.getFields().forEach(writer::addValue);
        writer.writeValuesToRow();
    }
    records.forEach(record -> {
        record.forEach(writer::addValue);
        writer.writeValuesToRow();
    });
    writer.close();
}
 

import com.univocity.parsers.csv.CsvWriter; //导入依赖的package包/类
public void writeTable(ITable table) throws IOException {
    Schema schema = table.getSchema();
    ColumnAndConverterDescription[] ccds =
            ColumnAndConverterDescription.create(schema.getColumnNames());
    ColumnAndConverter[] cols = table.getLoadedColumns(ccds);

    CsvWriterSettings settings = new CsvWriterSettings();
    CsvFormat format = new CsvFormat();
    format.setDelimiter(this.separator);
    settings.setFormat(format);
    settings.setEmptyValue("\"\"");
    settings.setNullValue(null);
    try (Writer fw = new FileWriter(this.file.toString())) {
        CsvWriter writer = new CsvWriter(fw, settings);

        String[] data = new String[schema.getColumnCount()];
        int index = 0;
        for (String c : schema.getColumnNames()) {
            data[index] = c;
            index++;
        }
        if (this.writeHeaderRow)
            writer.writeHeaders(data);
        IRowIterator rowIter = table.getMembershipSet().getIterator();
        int nextRow = rowIter.getNextRow();
        while (nextRow >= 0) {
            for (index = 0; index < cols.length; index++) {
                String d = cols[index].isMissing(nextRow) ? null : cols[index].asString(nextRow);
                data[index] = d;
            }
            writer.writeRow(data);
            nextRow = rowIter.getNextRow();
        }
    }
}
 

import com.univocity.parsers.csv.CsvWriter; //导入依赖的package包/类
public void csvWriterTest() throws IOException {
    // The Csv writer we are using has a bug, reproduced with this test.
    String[] data = new String[]{ "", null };
    CsvWriterSettings settings = new CsvWriterSettings();
    CsvFormat format = new CsvFormat();
    settings.setFormat(format);
    settings.setEmptyValue("\"\"");
    settings.setNullValue("");
    Writer fw = new FileWriter("tmp");
    CsvWriter writer = new CsvWriter(fw, settings);
    writer.writeRow(data);
    writer.close();
    fw.close();
}
 

import com.univocity.parsers.csv.CsvWriter; //导入依赖的package包/类
public void writeToStream(DataFrame df, Writer out) throws IOException {
    String[] columnNames = df.getSchema().getColumnNames().toArray(new String[0]);
    CsvWriter writer = new CsvWriter(out, new CsvWriterSettings());
    writer.writeHeaders(columnNames);

    List<Row> rows = df.getRows();
    for (Row curRow : rows) {
        List<Object> rowValues = curRow.getVals();
        writer.writeRow(rowValues);
    }
    writer.close();
}
 

import com.univocity.parsers.csv.CsvWriter; //导入依赖的package包/类
@Test(expectedExceptions = TextWritingException.class)
public void testException(){
	CsvWriterSettings settings = new CsvWriterSettings();
	settings.setHeaders("col2", "col5", "col3", "col4", "col1", "col6");
	StringWriter out = new StringWriter();
	CsvWriter writer = new CsvWriter(out, settings);

	Map<String, Object> rowData = new HashMap<String, Object>();
	for (int i = 1; i <= 4; i++) {
		rowData.put("col" + i, "inh" + i);
	}

	writer.processRecord(rowData);
}
 

import com.univocity.parsers.csv.CsvWriter; //导入依赖的package包/类
@Test(expectedExceptions = DataProcessingException.class)
public void testMapRecords() {
	final ObjectRowWriterProcessor clientProcessor = new ObjectRowWriterProcessor();
	final ObjectRowWriterProcessor accountProcessor = new ObjectRowWriterProcessor();

	OutputValueSwitch writerSwitch = new OutputValueSwitch();
	writerSwitch.addSwitchForValue("Account", accountProcessor, "type", "balance", "bank", "account", "swift");
	writerSwitch.addSwitchForValue("Client", clientProcessor);

	CsvWriterSettings settings = new CsvWriterSettings();
	settings.setExpandIncompleteRows(true);
	settings.getFormat().setLineSeparator("\n");
	settings.setHeaderWritingEnabled(false);
	settings.setRowWriterProcessor(writerSwitch);

	StringWriter output = new StringWriter();
	CsvWriter writer = new CsvWriter(output, settings);

	Map<String, Object> rowData = new LinkedHashMap<String, Object>();
	rowData.put("balance", "sp2");
	rowData.put("type", "Account"); //account NOT in first position to force an exception to happen.
	rowData.put("bank", "sp3");
	rowData.put("acount", "sp4");
	rowData.put("swift", "sp5");
	writer.processRecord(rowData);
	writer.close();

}
 

import com.univocity.parsers.csv.CsvWriter; //导入依赖的package包/类
@Test
public void testMultiple() {
	OutputValueSwitch writerSwitch = new OutputValueSwitch("type");
	writerSwitch.addSwitchForValue("SUPER", new ObjectRowWriterProcessor(), "type", "h1", "h2", "h3", "h4");
	writerSwitch.addSwitchForValue("SUB1", new ObjectRowWriterProcessor(), "type", "a", "b", "c", "d", "e", "f", "g");
	writerSwitch.addSwitchForValue("SUB2", new ObjectRowWriterProcessor(), "type", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z");

	CsvWriterSettings settings = new CsvWriterSettings();
	settings.setExpandIncompleteRows(true);
	settings.getFormat().setLineSeparator("\n");
	settings.setHeaderWritingEnabled(false);
	settings.setRowWriterProcessor(writerSwitch);

	StringWriter output = new StringWriter();
	CsvWriter writer = new CsvWriter(output, settings);

	writer.writeRow(newMap("SUPER", "h1=>v1;h2=>v2;h3=>v3;h4=>v4"));
	writer.writeRow(newMap("SUB1", "a=>v5;d=>v6;e=>v7;g=>v8"));
	writer.writeRow(newMap("SUB2", "q=>v9;u=>v10;w=>v11;y=>v12"));
	writer.writeRow(newMap("SUB1", "a=>v13;d=>v14;g=>v15"));
	writer.writeRow(newMap("SUB1", "a=>v16;d=>v17;f=>v18"));
	writer.close();

	assertEquals(output.toString(), "" +
			"SUPER,v1,v2,v3,v4\n" +
			"SUB1,v5,,,v6,v7,,v8\n" +
			"SUB2,,v9,,,,v10,,v11,,v12,\n" +
			"SUB1,v13,,,v14,,,v15\n" +
			"SUB1,v16,,,v17,,v18,\n");

}
 

import com.univocity.parsers.csv.CsvWriter; //导入依赖的package包/类
private void writeDuplicateReductionContext(DuplicateReductionContext duplicateReductionContext, CsvWriter csvWriter) {
    csvWriter.writeValue("Missing Real Representatives", duplicateReductionContext.getRepresentationDiff());
    csvWriter.writeValue("Duplicates Real Representatives", duplicateReductionContext.getDuplicatesRealRepresentatives());
    csvWriter.writeValue("duplicatesRemoved", duplicateReductionContext.getDuplicatesRemoved());
    csvWriter.writeValue("Power of Real Reap - Recall", duplicateReductionContext.getRepresentativesPower());
    csvWriter.writeValue("Wisdom of the crowd - Precision", duplicateReductionContext.getWisdomCrowds());
    csvWriter.writeValue("Average number of blocks", duplicateReductionContext.getNumberOfDirtyBlocks());
    csvWriter.writeValue("Average block size", duplicateReductionContext.getAverageBlockSize());

    csvWriter.writeValuesToRow();
}
 

import com.univocity.parsers.csv.CsvWriter; //导入依赖的package包/类
public void writeComparisonExperimentsMeasurements(Multimap<String, DuplicateReductionContext> results, File expResults) {
    CsvWriterSettings settings = new CsvWriterSettings();
    settings.setHeaders(HEADERS_BASELINE_AND_ALG);
    settings.selectFields(HEADERS_BASELINE_AND_ALG);

    CsvWriter csvWriter = dataParser.preparOutputFile(expResults, settings);
    csvWriter.writeHeaders();

    for (Map.Entry<String, DuplicateReductionContext> entry : results.entries()) {
        csvWriter.writeRow(buildComparisonRow(entry));
    }
    csvWriter.close();
}