20个非常有用的Java程序片段

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篇首语:本文由小常识网(cha138.com)小编为大家整理,主要介绍了20个非常有用的Java程序片段相关的知识,希望对你有一定的参考价值。

1. 字符串有整型的相互转换

String a = String.valueOf(2);   //integer to numeric string  
int i = Integer.parseInt(a); //numeric string to an int

2. 向文件末尾添加内容

BufferedWriter out = null;  
try {  
    out = new BufferedWriter(new FileWriter(”filename”, true));  
    out.write(”aString”);  
} catch (IOException e) {  
    // error processing code  
} finally {  
    if (out != null) {  
        out.close();  
    }  
}

3. 得到当前方法的名字

String methodName = Thread.currentThread().getStackTrace()[1].getMethodName();

4. 转字符串到日期

java.util.Date = java.text.DateFormat.getDateInstance().parse(date String);

或者是:

SimpleDateFormat format = new SimpleDateFormat( "dd.MM.yyyy" );  
Date date = format.parse( myString );

5. 使用JDBC链接Oracle

public class OracleJdbcTest  
{  
    String driverClass = "oracle.jdbc.driver.OracleDriver";  

    Connection con;  

    public void init(FileInputStream fs) throws ClassNotFoundException, SQLException, FileNotFoundException, IOException  
    {  
        Properties props = new Properties();  
        props.load(fs);  
        String url = props.getProperty("db.url");  
        String userName = props.getProperty("db.user");  
        String password = props.getProperty("db.password");  
        Class.forName(driverClass);  

        con=DriverManager.getConnection(url, userName, password);  
    }  

    public void fetch() throws SQLException, IOException  
    {  
        PreparedStatement ps = con.prepareStatement("select SYSDATE from dual");  
        ResultSet rs = ps.executeQuery();  

        while (rs.next())  
        {  
            // do the thing you do  
        }  
        rs.close();  
        ps.close();  
    }  

    public static void main(String[] args)  
    {  
        OracleJdbcTest test = new OracleJdbcTest();  
        test.init();  
        test.fetch();  
    }  
}

6. 把 Java util.Date 转成 sql.Date

java.util.Date utilDate = new java.util.Date();  
java.sql.Date sqlDate = new java.sql.Date(utilDate.getTime());

7. 使用NIO进行快速的文件拷贝

public static void fileCopy( File in, File out )  
            throws IOException  
    {  
        FileChannel inChannel = new FileInputStream( in ).getChannel();  
        FileChannel outChannel = new FileOutputStream( out ).getChannel();  
        try 
        {  
//          inChannel.transferTo(0, inChannel.size(), outChannel);      // original -- apparently has trouble copying large files on Windows  

            // magic number for Windows, 64Mb - 32Kb)  
            int maxCount = (64 * 1024 * 1024) - (32 * 1024);  
            long size = inChannel.size();  
            long position = 0;  
            while ( position < size )  
            {  
               position += inChannel.transferTo( position, maxCount, outChannel );  
            }  
        }  
        finally 
        {  
            if ( inChannel != null )  
            {  
               inChannel.close();  
            }  
            if ( outChannel != null )  
            {  
                outChannel.close();  
            }  
        }  
    }

8. 创建图片的缩略图

private void createThumbnail(String filename, int thumbWidth, int thumbHeight, int quality, String outFilename)  
        throws InterruptedException, FileNotFoundException, IOException  
    {  
        // load image from filename  
        Image image = Toolkit.getDefaultToolkit().getImage(filename);  
        MediaTracker mediaTracker = new MediaTracker(new Container());  
        mediaTracker.addImage(image, 0);  
        mediaTracker.waitForID(0);  
        // use this to test for errors at this point: System.out.println(mediaTracker.isErrorAny());  

        // determine thumbnail size from WIDTH and HEIGHT  
        double thumbRatio = (double)thumbWidth / (double)thumbHeight;  
        int imageWidth = image.getWidth(null);  
        int imageHeight = image.getHeight(null);  
        double imageRatio = (double)imageWidth / (double)imageHeight;  
        if (thumbRatio < imageRatio) {  
            thumbHeight = (int)(thumbWidth / imageRatio);  
        } else {  
            thumbWidth = (int)(thumbHeight * imageRatio);  
        }  

        // draw original image to thumbnail image object and  
        // scale it to the new size on-the-fly  
        BufferedImage thumbImage = new BufferedImage(thumbWidth, thumbHeight, BufferedImage.TYPE_INT_RGB);  
        Graphics2D graphics2D = thumbImage.createGraphics();  
        graphics2D.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);  
        graphics2D.drawImage(image, 0, 0, thumbWidth, thumbHeight, null);  

        // save thumbnail image to outFilename  
        BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(outFilename));  
        JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);  
        JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(thumbImage);  
        quality = Math.max(0, Math.min(quality, 100));  
        param.setQuality((float)quality / 100.0f, false);  
        encoder.setJPEGEncodeParam(param);  
        encoder.encode(thumbImage);  
        out.close();  
    }

9. 创建 JSON 格式的数据

请先阅读这篇文章 了解一些细节,

并下面这个JAR 文件:json-rpc-1.0.jar (75 kb)

import org.json.JSONObject;  
...  
...  
JSONObject json = new JSONObject();  
json.put("city", "Mumbai");  
json.put("country", "India");  
...  
String output = json.toString();  
...

10. 使用iText JAR生成PDF

阅读这篇文章 了解更多细节

import java.io.File;  
import java.io.FileOutputStream;  
import java.io.OutputStream;  
import java.util.Date;  

import com.lowagie.text.Document;  
import com.lowagie.text.Paragraph;  
import com.lowagie.text.pdf.PdfWriter;  

public class GeneratePDF {  

    public static void main(String[] args) {  
        try {  
            OutputStream file = new FileOutputStream(new File("C:\\Test.pdf"));  

            Document document = new Document();  
            PdfWriter.getInstance(document, file);  
            document.open();  
            document.add(new Paragraph("Hello Kiran"));  
            document.add(new Paragraph(new Date().toString()));  

            document.close();  
            file.close();  

        } catch (Exception e) {  

            e.printStackTrace();  
        }  
    }  
}

11. HTTP 代理设置

阅读这篇 文章 了解更多细节。

System.getProperties().put("http.proxyHost", "someProxyURL");  
System.getProperties().put("http.proxyPort", "someProxyPort");  
System.getProperties().put("http.proxyUser", "someUserName");  
System.getProperties().put("http.proxyPassword", "somePassword");

12. 单实例Singleton 示例

请先阅读这篇文章 了解更多信息

public class SimpleSingleton {  
    private static SimpleSingleton singleInstance =  new SimpleSingleton();  

    //Marking default constructor private  
    //to avoid direct instantiation.  
    private SimpleSingleton() {  
    }  

    //Get instance for class SimpleSingleton  
    public static SimpleSingleton getInstance() {  

        return singleInstance;  
    }  
}

另一种实现

public enum SimpleSingleton {  
    INSTANCE;  
    public void doSomething() {  
    }  
}  

//Call the method from Singleton:  
SimpleSingleton.INSTANCE.doSomething();

13. 抓屏程序

阅读这篇文章 获得更多信息。

import java.awt.Dimension;  
import java.awt.Rectangle;  
import java.awt.Robot;  
import java.awt.Toolkit;  
import java.awt.image.BufferedImage;  
import javax.imageio.ImageIO;  
import java.io.File;  

...  

public void captureScreen(String fileName) throws Exception {  

   Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();  
   Rectangle screenRectangle = new Rectangle(screenSize);  
   Robot robot = new Robot();  
   BufferedImage image = robot.createScreenCapture(screenRectangle);  
   ImageIO.write(image, "png", new File(fileName));  

}  
...

14. 列出文件和目录

File dir = new File("directoryName");  
  String[] children = dir.list();  
  if (children == null) {  
      // Either dir does not exist or is not a directory  
  } else {  
      for (int i=0; i < children.length; i++) {  
          // Get filename of file or directory  
          String filename = children[i];  
      }  
  }  

  // It is also possible to filter the list of returned files.  
  // This example does not return any files that start with `.‘.  
  FilenameFilter filter = new FilenameFilter() {  
      public boolean accept(File dir, String name) {  
          return !name.startsWith(".");  
      }  
  };  
  children = dir.list(filter);  

  // The list of files can also be retrieved as File objects  
  File[] files = dir.listFiles();  

  // This filter only returns directories  
  FileFilter fileFilter = new FileFilter() {  
      public boolean accept(File file) {  
          return file.isDirectory();  
      }  
  };  
  files = dir.listFiles(fileFilter);

15. 创建ZIP和JAR文件

import java.util.zip.*;  
import java.io.*;  

public class ZipIt {  
    public static void main(String args[]) throws IOException {  
        if (args.length < 2) {  
            System.err.println("usage: java ZipIt Zip.zip file1 file2 file3");  
            System.exit(-1);  
        }  
        File zipFile = new File(args[0]);  
        if (zipFile.exists()) {  
            System.err.println("Zip file already exists, please try another");  
            System.exit(-2);  
        }  
        FileOutputStream fos = new FileOutputStream(zipFile);  
        ZipOutputStream zos = new ZipOutputStream(fos);  
        int bytesRead;  
        byte[] buffer = new byte[1024];  
        CRC32 crc = new CRC32();  
        for (int i=1, n=args.length; i < n; i++) {  
            String name = args[i];  
            File file = new File(name);  
            if (!file.exists()) {  
                System.err.println("Skipping: " + name);  
                continue;  
            }  
            BufferedInputStream bis = new BufferedInputStream(  
                new FileInputStream(file));  
            crc.reset();  
            while ((bytesRead = bis.read(buffer)) != -1) {  
                crc.update(buffer, 0, bytesRead);  
            }  
            bis.close();  
            // Reset to beginning of input stream  
            bis = new BufferedInputStream(  
                new FileInputStream(file));  
            ZipEntry entry = new ZipEntry(name);  
            entry.setMethod(ZipEntry.STORED);  
            entry.setCompressedSize(file.length());  
            entry.setSize(file.length());  
            entry.setCrc(crc.getValue());  
            zos.putNextEntry(entry);  
            while ((bytesRead = bis.read(buffer)) != -1) {  
                zos.write(buffer, 0, bytesRead);  
            }  
            bis.close();  
        }  
        zos.close();  
    }  
}

16. 解析/读取XML 文件

XML文件

<?xml version="1.0"?> 
<students> 
    <student> 
        <name>John</name> 
        <grade>B</grade> 
        <age>12</age> 
    </student> 
    <student> 
        <name>Mary</name> 
        <grade>A</grade> 
        <age>11</age> 
    </student> 
    <student> 
        <name>Simon</name> 
        <grade>A</grade> 
        <age>18</age> 
    </student> 
</students>

Java代码

package net.viralpatel.java.xmlparser;  

import java.io.File;  
import javax.xml.parsers.DocumentBuilder;  
import javax.xml.parsers.DocumentBuilderFactory;  

import org.w3c.dom.Document;  
import org.w3c.dom.Element;  
import org.w3c.dom.Node;  
import org.w3c.dom.NodeList;  

public class XMLParser {  

    public void getAllUserNames(String fileName) {  
        try {  
            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();  
            DocumentBuilder db = dbf.newDocumentBuilder();  
            File file = new File(fileName);  
            if (file.exists()) {  
                Document doc = db.parse(file);  
                Element docEle = doc.getDocumentElement();  

                // Print root element of the document  
                System.out.println("Root element of the document: " 
                        + docEle.getNodeName());  

                NodeList studentList = docEle.getElementsByTagName("student");  

                // Print total student elements in document  
                System.out  
                        .println("Total students: " + studentList.getLength());  

                if (studentList != null && studentList.getLength() > 0) {  
                    for (int i = 0; i < studentList.getLength(); i++) {  

                        Node node = studentList.item(i);  

                        if (node.getNodeType() == Node.ELEMENT_NODE) {  

                            System.out  
                                    .println("=====================");  

                            Element e = (Element) node;  
                            NodeList nodeList = e.getElementsByTagName("name");  
                            System.out.println("Name: " 
                                    + nodeList.item(0).getChildNodes().item(0)  
                                            .getNodeValue());  

                            nodeList = e.getElementsByTagName("grade");  
                            System.out.println("Grade: " 
                                    + nodeList.item(0).getChildNodes().item(0)  
                                            .getNodeValue());  

                            nodeList = e.getElementsByTagName("age");  
                            System.out.println("Age: " 
                                    + nodeList.item(0).getChildNodes().item(0)  
                                            .getNodeValue());  
                        }  
                    }  
                } else {  
                    System.exit(1);  
                }  
            }  
        } catch (Exception e) {  
            System.out.println(e);  
        }  
    }  
    public static void main(String[] args) {  

        XMLParser parser = new XMLParser();  
        parser.getAllUserNames("c:\\test.xml");  
    }  
}

17. 把 Array 转换成 Map

import java.util.Map;  
import org.apache.commons.lang.ArrayUtils;  

public class Main {  

  public static void main(String[] args) {  
    String[][] countries = { { "United States", "New York" }, { "United Kingdom", "London" },  
        { "Netherland", "Amsterdam" }, { "Japan", "Tokyo" }, { "France", "Paris" } };  

    Map countryCapitals = ArrayUtils.toMap(countries);  

    System.out.println("Capital of Japan is " + countryCapitals.get("Japan"));  
    System.out.println("Capital of France is " + countryCapitals.get("France"));  
  }  
}

18. 发送邮件

import javax.mail.*;  
import javax.mail.internet.*;  
import java.util.*;  

public void postMail( String recipients[ ], String subject, String message , String from) throws MessagingException  
{  
    boolean debug = false;  

     //Set the host smtp address  
     Properties props = new Properties();  
     props.put("mail.smtp.host", "smtp.example.com");  

    // create some properties and get the default Session  
    Session session = Session.getDefaultInstance(props, null);  
    session.setDebug(debug);  

    // create a message  
    Message msg = new MimeMessage(session);  

    // set the from and to address  
    InternetAddress addressFrom = new InternetAddress(from);  
    msg.setFrom(addressFrom);  

    InternetAddress[] addressTo = new InternetAddress[recipients.length];  
    for (int i = 0; i < recipients.length; i++)  
    {  
        addressTo[i] = new InternetAddress(recipients[i]);  
    }  
    msg.setRecipients(Message.RecipientType.TO, addressTo);  

    // Optional : You can also set your custom headers in the Email if you Want  
    msg.addHeader("MyHeaderName", "myHeaderValue");  

    // Setting the Subject and Content Type  
    msg.setSubject(subject);  
    msg.setContent(message, "text/plain");  
    Transport.send(msg);  
}

19. 发送代数据的HTTP 请求

import java.io.BufferedReader;  
import java.io.InputStreamReader;  
import java.net.URL;  

public class Main {  
    public static void main(String[] args)  {  
        try {  
            URL my_url = new URL("http://coolshell.cn/");  
            BufferedReader br = new BufferedReader(new InputStreamReader(my_url.openStream()));  
            String strTemp = "";  
            while(null != (strTemp = br.readLine())){  
            System.out.println(strTemp);  
        }  
        } catch (Exception ex) {  
            ex.printStackTrace();  
        }  
    }  
}

20. 改变数组的大小

/** 
* Reallocates an array with a new size, and copies the contents 
* of the old array to the new array. 
* @param oldArray  the old array, to be reallocated. 
* @param newSize   the new array size. 
* @return          A new array with the same contents. 
*/ 
private static Object resizeArray (Object oldArray, int newSize) {  
   int oldSize = java.lang.reflect.Array.getLength(oldArray);  
   Class elementType = oldArray.getClass().getComponentType();  
   Object newArray = java.lang.reflect.Array.newInstance(  
         elementType,newSize);  
   int preserveLength = Math.min(oldSize,newSize);  
   if (preserveLength > 0)  
      System.arraycopy (oldArray,0,newArray,0,preserveLength);  
   return newArray;  
}  

// Test routine for resizeArray().  
public static void main (String[] args) {  
   int[] a = {1,2,3};  
   a = (int[])resizeArray(a,5);  
   a[3] = 4;  
   a[4] = 5;  
   for (int i=0; i<a.length; i++)  
      System.out.println (a[i]);  
}
 
21.java操作excel
工具类:

package com.xxxxx.cnnvd.util;

import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.util.ArrayList; import java.util.Iterator;

import org.apache.poi.hssf.usermodel.HSSFCell; import org.apache.poi.hssf.usermodel.HSSFRow; import org.apache.poi.hssf.usermodel.HSSFSheet; import org.apache.poi.hssf.usermodel.HSSFWorkbook; import org.apache.poi.poifs.filesystem.POIFSFileSystem; import org.apache.poi.xssf.usermodel.XSSFCell; import org.apache.poi.xssf.usermodel.XSSFRow; import org.apache.poi.xssf.usermodel.XSSFSheet; import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class ReadExcelTool {    public ArrayList<ArrayList<String>> readExcel(String fileName,String path) {   ArrayList<ArrayList<String>> Row =new ArrayList<ArrayList<String>>();   try {        FileInputStream fileIn = new FileInputStream(new File(path,fileName));             POIFSFileSystem fs = new POIFSFileSystem(fileIn);             HSSFWorkbook wb = new HSSFWorkbook(fs);        for (int numSheet = 0; numSheet < wb.getNumberOfSheets(); numSheet++) {     HSSFSheet xssfSheet = wb.getSheetAt(numSheet);     if (xssfSheet == null) {      continue;     }     // 循环行Row     for (int rowNum = 1; rowNum <= xssfSheet.getLastRowNum(); rowNum++) {      HSSFRow xssfRow = xssfSheet.getRow(rowNum);      if (xssfRow == null) {       continue;      }            // 循环列Cell      ArrayList<String> cell =new ArrayList<String>();      for (int cellNum = 0; cellNum <= xssfRow.getLastCellNum(); cellNum++) {       HSSFCell xssfCell = xssfRow.getCell(cellNum);       if (xssfCell == null) {        continue;       }       cell.add(getValue(xssfCell));      }      Row.add(cell);     }    }   } catch (IOException e) {    e.printStackTrace();   }     return Row;  }

 private String getValue(HSSFCell xssfCell) {   if (xssfCell.getCellType() == xssfCell.CELL_TYPE_BOOLEAN) {    return String.valueOf(xssfCell.getBooleanCellValue());   } else if (xssfCell.getCellType() == xssfCell.CELL_TYPE_NUMERIC) {    return String.valueOf(xssfCell.getNumericCellValue());   } else {    return String.valueOf(xssfCell.getStringCellValue());   }  }    /**

//测试类  public static void main(String[] args) {   ReadExcelTool ret = new ReadExcelTool();   ArrayList<ArrayList<String>> datas = ret.readExcel("template.xls", "D:\\java\\tomcat60\\webapps\\zyst\\impfiles");   for (Iterator iterator = datas.iterator(); iterator.hasNext();) {    ArrayList<String> datas2 = (ArrayList<String>) iterator.next();    for (Iterator iterator2 = datas2.iterator(); iterator2.hasNext();) {     String name = (String) iterator2.next();     System.out.print(name);    }    System.out.println();       }  }  **/   }

使用工具类

 /**   * 检查文件的后缀名称是否xls   *   * @param fileFileName2   * @return 返回文件后缀名xls,若不符合则返回null   */  private String checkSuffix(String fileFileName2) {   if (fileFileName2 == null) {    return null;   }   String fileName = fileFileName2.substring(fileFileName2.lastIndexOf(".") + 1);   if (fileName.equals("xls")) {    return "xls";   }   return null;  }

 

 /**   * 把excel数据导入数据库   *   * @return   */  public String cnnvdImportSave() {   String path = sRequest.getSession().getServletContext().getRealPath("/uploadfiles");  // System.out.println(path);   //必须是符合格式的excel文件   if ("xls".equals(checkSuffix(fileFileName))) {    //路径    // ServletActionContext.getServletContext().getRealPath("/");    File savefile = new File(new File(path), fileFileName);    if (!savefile.getParentFile().exists()) {     savefile.getParentFile().mkdirs();    }    try {     FileUtils.copyFile(file, savefile);    } catch (IOException e) {     // TODO Auto-generated catch block     e.printStackTrace();    }    //读取excel文件    ReadExcelTool ret = new ReadExcelTool();    ArrayList<ArrayList<String>> datas = ret.readExcel(fileFileName, path);    //    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");    if (datas != null && datas.size() > 0) {     for (int i = 0; i < datas.size(); i++) {      List temp = datas.get(i);      if (temp != null && temp.size() > 0) {        String vulname = (String) temp.get(3);        String levelid = (String) temp.get(30);        String vultype = (String) temp.get(39);        String vulpubtime = (String) temp.get(13);        String vulreptime = (String) temp.get(14);        Date vulpubtimeDate = null;        Date vulreptimeDate = null;        try {         vulpubtimeDate = sdf.parse(vulpubtime);         vulreptimeDate = sdf.parse(vulreptime);        } catch (ParseException e) {         // TODO Auto-generated catch block         e.printStackTrace();        }        String vulorg = (String) temp.get(40);        String vulsummary = (String) temp.get(4);        String pub = (String) temp.get(55);        String refurl = (String) temp.get(19);        String cnnvdid = (String) temp.get(1);        String cveid = (String) temp.get(9);        String bid = (String) temp.get(10);        //通过cnnvdid判断该条数据是否已存在,存在就先删除,再新增        if (vulnerabilityService.checkCnnvdIdExist(cnnvdid) != null) {         String sql4delete = "delete from t_cnnvd_vulnerability where cnnvdid = ?";         jdbcTemplate.update(sql4delete,cnnvdid);        }        String sql = "insert into t_cnnvd_xxxxxxx(vulname,levelid,vultype,vulpubtime,vulreptime,vulorg,vulsummary,pub,refurl,cnnvdid,cveid,bid) values(?,?,?,?,?,?,?,?,?,?,?,?)";        jdbcTemplate.update(sql,vulname,levelid,vultype,vulpubtime,vulreptime,vulorg,vulsummary,pub,refurl,cnnvdid,cveid,bid);      }     }    }    //把生成的临时文件删除    savefile.delete();    request.put("cnnvdImportResult", "success");    return SUCCESS;    }   return ERROR;  }

 

22.java操作csv,使用CsvReader,需要下载使用javacsv.jar

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;
import org.apache.log4j.Logger;
import com.csvreader.CsvReader;
import com.csvreader.CsvWriter;
/**
 * CSV测试类
 *
 */
public class CSVTest {
protected static Logger logger = Logger.getLogger(CSVTest.class); /**
 * 读取CSV文件
 * @param file
 * @return
 */
public static List<String[]> readCsv(String file) {
List<String[]> list = new ArrayList<String[]>();
CsvReader reader = null;
try {
// 初始化CsvReader并指定列分隔符和字符编码
reader = new CsvReader(file, ‘,‘, Charset.forName("GBK"));
while (reader.readRecord()) {
// 读取每行数据以数组形式返回
String[] str = reader.getValues();
if (str != null && str.length > 0) {

					//reader.getCurrentRecord()得到当前记录的行号,第一行是头,不使用
					if ((reader.getCurrentRecord() != 0) && (str != null) && (str.length > 0)) {
						System.out.println(str.length);
						System.out.println(str[1]);
						list.add(str);
					}
				}
			}
		} catch (FileNotFoundException e) {
			logger.error(e.getMessage(), e);
		} catch (IOException e) {
			logger.error(e.getMessage(), e);
		} finally {
			if (reader != null) {
				reader.close();
			}
		}
		return list;
	}

 

/**   * 写入CSV文件   */  public static void writeCsv(List<String[]> content, String path) {  CsvWriter writer = null;  try {  writer = new CsvWriter(path, ‘,‘, Charset.forName("GBK"));  if(content != null && content.size() != 0) {  for(String[] strArray : content) {  writer.writeRecord(strArray);  }  } else {  // 做异常处理  }  } catch (IOException e) {  logger.error(e.getMessage(), e);  } finally {  if(writer != null) {  writer.close(); }  }  }

 

/**   * @param args   * @throws Exception   */  public static void main(String[] args) throws Exception {  String readPath = "F:" + File.separator + "test" + File.separator + "muti-test.csv"; String writePath = "F:" + File.separator + "test" + File.separator + "muti-test-output.csv";  List<String[]> result = readCsv(readPath);  for(String[] strArray : result) {  for(String s : strArray) {  System.out.print(s + ",");  }  System.out.println();  }  writeCsv(result, writePath);  Thread.sleep(999999);  } }





























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