[英]Unable to Parse header from github CSV URL using Apache Commons
[英]Write CSV from List of HashMaps with Header using Apache Commons CSV
我必须使用HashMap
的ArrayList
并使用Apache Commons CSV创建CSV。 但是,它没有将值写入正确的标题。 有没有一种简单的方法可以使库使用Enum自动将值放置在正确的标题中? 我不想手动分配它,因为我将添加更多列。
这是它产生的:
这是我所拥有的:
头文件
public enum Header
{
FIRST_NAME(),
LAST_NAME(),
GENDER();
}
主要
public static void main(String[] args)
{
List<Map<Header, String>> output = new ArrayList<>();
Map<Header, String> map = new HashMap<>();
map.put(Header.FIRST_NAME, "John");
map.put(Header.LAST_NAME, "Andrew");
map.put(Header.GENDER, "Male");
output.add(map);
Map<Header, String> map2 = new HashMap<>();
map2.put(Header.FIRST_NAME, "Sally");
map2.put(Header.LAST_NAME, "Andrew");
map2.put(Header.GENDER, "Female");
output.add(map2);
String outputFile = System.getProperty("java.io.tmpdir")+"test.csv";
try (
BufferedWriter writer = Files.newBufferedWriter(Paths.get(outputFile));
CSVPrinter csvPrinter = new CSVPrinter(writer, CSVFormat.DEFAULT
.withHeader(Header.class));)
{
csvPrinter.printRecords(output);
csvPrinter.flush();
} catch (IOException ex)
{
Logger.getLogger(TestCSV.class.getName()).log(Level.SEVERE, null, ex);
}
}
这个怎么样:
try (BufferedWriter writer = Files.newBufferedWriter(Paths.get(outputFile));
CSVPrinter csvPrinter = new CSVPrinter(writer, CSVFormat.DEFAULT.withHeader(Header.class));) {
for (Map<Header, String> row : output) {
csvPrinter.printRecord(Arrays.asList(Header.values())
.stream()
.map(header -> row.get(header))
.collect(Collectors.toList()));
}
} catch (IOException ex) {
Logger.getLogger(TestCSV.class.getName())
.log(Level.SEVERE, null, ex);
}
确定了。 我将地图更改为LinkedHashMap
以保留顺序,然后执行以下操作:
try (BufferedWriter writer = Files.newBufferedWriter(Paths.get(outputFile));
CSVPrinter csvPrinter = new CSVPrinter(writer, CSVFormat.DEFAULT
.withHeader(Header.class));)
{
for (Map<Header, String> val : output)
{
csvPrinter.printRecord(val.values().toArray());
}
csvPrinter.flush();
} catch (IOException ex)
{
Logger.getLogger(TestCSV.class.getName()).log(Level.SEVERE, null, ex);
}
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