JAVA導(dǎo)出CSV文件實(shí)例教程
以前導(dǎo)出總是用POI導(dǎo)出為Excel文件,后來(lái)當(dāng)我了解到CSV以后,我發(fā)現(xiàn)速度飛快。
如果導(dǎo)出的數(shù)據(jù)不要求格式、樣式、公式等等,建議最好導(dǎo)成CSV文件,因?yàn)檎娴暮芸臁?/p>
雖然我們可以用Java再帶的文件相關(guān)的類去操作以生成一個(gè)CSV文件,但事實(shí)上有好多第三方類庫(kù)也提供了類似的功能。
這里我們使用apache提供的commons-csv組件
Commons CSV
文檔在這里
http://commons.apache.org/proper/commons-csv/
http://commons.apache.org/proper/commons-csv/user-guide.html
先看一下具體用法
@Test public void testWrite() throws Exception { FileOutputStream fos = new FileOutputStream("E:/cjsworkspace/cjs-excel-demo/target/abc.csv"); OutputStreamWriter osw = new OutputStreamWriter(fos, "GBK"); CSVFormat csvFormat = CSVFormat.DEFAULT.withHeader("姓名", "年齡", "家鄉(xiāng)"); CSVPrinter csvPrinter = new CSVPrinter(osw, csvFormat);// csvPrinter = CSVFormat.DEFAULT.withHeader("姓名", "年齡", "家鄉(xiāng)").print(osw); for (int i = 0; i < 10; i++) { csvPrinter.printRecord("張三", 20, "湖北"); } csvPrinter.flush(); csvPrinter.close(); } @Test public void testRead() throws IOException { InputStream is = new FileInputStream("E:/cjsworkspace/cjs-excel-demo/target/abc.csv"); InputStreamReader isr = new InputStreamReader(is, "GBK"); Reader reader = new BufferedReader(isr); CSVParser parser = CSVFormat.EXCEL.withHeader("name", "age", "jia").parse(reader);// CSVParser csvParser = CSVParser.parse(reader, CSVFormat.DEFAULT.withHeader("name", "age", "jia")); List<CSVRecord> list = parser.getRecords(); for (CSVRecord record : list) { System.out.println(record.getRecordNumber() + ":" + record.get("name") + ":" + record.get("age") + ":" + record.get("jia")); } parser.close(); } /** * Parsing an Excel CSV File */ @Test public void testParse() throws Exception { Reader reader = new FileReader("C:/Users/Administrator/Desktop/abc.csv"); CSVParser parser = CSVFormat.EXCEL.parse(reader); for (CSVRecord record : parser.getRecords()) { System.out.println(record); } parser.close(); } /** * Defining a header manually */ @Test public void testParseWithHeader() throws Exception { Reader reader = new FileReader("C:/Users/Administrator/Desktop/abc.csv"); CSVParser parser = CSVFormat.EXCEL.withHeader("id", "name", "code").parse(reader); for (CSVRecord record : parser.getRecords()) { System.out.println(record.get("id") + "," + record.get("name") + "," + record.get("code")); } parser.close(); } /** * Using an enum to define a header */ enum MyHeaderEnum { ID, NAME, CODE; } @Test public void testParseWithEnum() throws Exception { Reader reader = new FileReader("C:/Users/Administrator/Desktop/abc.csv"); CSVParser parser = CSVFormat.EXCEL.withHeader(MyHeaderEnum.class).parse(reader); for (CSVRecord record : parser.getRecords()) { System.out.println(record.get(MyHeaderEnum.ID) + "," + record.get(MyHeaderEnum.NAME) + "," + record.get(MyHeaderEnum.CODE)); } parser.close(); } private List<Map<String, String>> recordList = new ArrayList<>(); @Before public void init() { for (int i = 0; i < 5; i++) { Map<String, String> map = new HashMap<>(); map.put("name", "zhangsan"); map.put("code", "001"); recordList.add(map); } } @Test public void writeMuti() throws InterruptedException { ExecutorService executorService = Executors.newFixedThreadPool(3); CountDownLatch doneSignal = new CountDownLatch(2); executorService.submit(new exprotThread("E:/0.csv", recordList, doneSignal)); executorService.submit(new exprotThread("E:/1.csv", recordList, doneSignal)); doneSignal.await(); System.out.println("Finish!!!"); } class exprotThread implements Runnable { private String filename; private List<Map<String, String>> list; private CountDownLatch countDownLatch; public exprotThread(String filename, List<Map<String, String>> list, CountDownLatch countDownLatch) { this.filename = filename; this.list = list; this.countDownLatch = countDownLatch; } @Override public void run() { try { CSVPrinter printer = new CSVPrinter(new FileWriter(filename), CSVFormat.EXCEL.withHeader("NAME", "CODE")); for (Map<String, String> map : list) { printer.printRecord(map.values()); } printer.close(); countDownLatch.countDown(); } catch (IOException e) { e.printStackTrace(); } } }
CSV與EXCEL
/** * 測(cè)試寫100萬(wàn)數(shù)據(jù)需要花費(fèi)多長(zhǎng)時(shí)間 */ @Test public void testMillion() throws Exception { int times = 10000 * 10; Object[] cells = {"滿100減15元", "100011", 15}; // 導(dǎo)出為CSV文件 long t1 = System.currentTimeMillis(); FileWriter writer = new FileWriter("G:/test1.csv"); CSVPrinter printer = CSVFormat.EXCEL.print(writer); for (int i = 0; i < times; i++) { printer.printRecord(cells); } printer.flush(); printer.close(); long t2 = System.currentTimeMillis(); System.out.println("CSV: " + (t2 - t1)); // 導(dǎo)出為Excel文件 long t3 = System.currentTimeMillis(); XSSFWorkbook workbook = new XSSFWorkbook(); XSSFSheet sheet = workbook.createSheet(); for (int i = 0; i < times; i++) { XSSFRow row = sheet.createRow(i); for (int j = 0; j < cells.length; j++) { XSSFCell cell = row.createCell(j); cell.setCellValue(String.valueOf(cells[j])); } } FileOutputStream fos = new FileOutputStream("G:/test2.xlsx"); workbook.write(fos); fos.flush(); fos.close(); long t4 = System.currentTimeMillis(); System.out.println("Excel: " + (t4 - t3)); }
Maven依賴
<dependencies> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-csv</artifactId> <version>1.5</version> </dependency> <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi</artifactId> <version>3.17</version> </dependency> <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi-ooxml</artifactId> <version>3.17</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> <scope>test</scope> </dependency></dependencies>
最后,剛才的例子中只寫了3個(gè)字段,100萬(wàn)行,生成的CSV文件有十幾二十兆,太多的話建議分多個(gè)文件打包下周,不然想象一個(gè)打開一個(gè)幾百兆的excel都費(fèi)勁。
以上就是JAVA導(dǎo)出CSV文件實(shí)例教程的詳細(xì)內(nèi)容,更多關(guān)于JAVA導(dǎo)出CSV文件的資料請(qǐng)關(guān)注腳本之家其它相關(guān)文章!
相關(guān)文章
SpringCloud 微服務(wù)最佳開發(fā)實(shí)踐
本文結(jié)合我們實(shí)際的開發(fā)中遇到的一些問(wèn)題整理出了一份微服務(wù)開發(fā)的實(shí)踐規(guī)范,對(duì)SpringCloud 微服務(wù)開發(fā)實(shí)踐相關(guān)知識(shí)感興趣的朋友一起看看吧2021-07-07Java中Controller引起的Ambiguous?mapping問(wèn)題及解決
這篇文章主要介紹了Java中Controller引起的Ambiguous?mapping問(wèn)題及解決,具有很好的參考價(jià)值,希望對(duì)大家有所幫助。如有錯(cuò)誤或未考慮完全的地方,望不吝賜教2022-10-10使用lombok@Data啟動(dòng)項(xiàng)目報(bào)錯(cuò)問(wèn)題及解決
在使用Lombok時(shí),可能會(huì)遇到實(shí)體類中的@Data注解不生效,導(dǎo)致get方法找不到的問(wèn)題,解決這一問(wèn)題通常需要三個(gè)步驟:首先,檢查項(xiàng)目設(shè)置中編譯規(guī)則是否勾選;其次,確認(rèn)IDE中是否安裝了Lombok插件2024-10-10Druid關(guān)閉監(jiān)控頁(yè)面關(guān)閉不了的問(wèn)題及解決
這篇文章主要介紹了Druid關(guān)閉監(jiān)控頁(yè)面關(guān)閉不了的問(wèn)題及解決方案,具有很好的參考價(jià)值,希望對(duì)大家有所幫助,如有錯(cuò)誤或未考慮完全的地方,望不吝賜教2024-05-05Jvm調(diào)優(yōu)和SpringBoot項(xiàng)目?jī)?yōu)化的詳細(xì)教程
這篇文章主要介紹了Jvm調(diào)優(yōu)和SpringBoot項(xiàng)目?jī)?yōu)化,本文通過(guò)圖文并茂的形式給大家介紹的非常詳細(xì),對(duì)大家的學(xué)習(xí)或工作具有一定的參考借鑒價(jià)值,需要的朋友可以參考下2020-09-09如何解決Maven無(wú)法拉取SNAPSHOT依賴問(wèn)題
在使用Maven管理項(xiàng)目時(shí),可能會(huì)遇到無(wú)法拉取SNAPSHOT版本依賴的問(wèn)題,這通常是因?yàn)镸aven默認(rèn)不支持直接拉取SNAPSHOT版本,遇到這樣的問(wèn)題,可以通過(guò)在項(xiàng)目的pom.xml文件中添加<repositories>標(biāo)簽,并配置啟用SNAPSHOT的倉(cāng)庫(kù)地址來(lái)解決2024-10-10