java写csv文件的问题：报错
ClassLoader classLoader = CsvTest.class.getClassLoader(); File file = new File(classLoader.getResource("csv.csv").getFile()); OutputStream os = new FileOutputStream(file); CsvWriter cw = new CsvWriter(os, ',', Charset.forName("utf-8")); cw.write("hello world");
ClassLoader classLoader = CsvTest.class.getClassLoader(); File file = new File(classLoader.getResource("test.csv").getFile()); BufferedWriter bw = new BufferedWriter(new FileWriter(file,true)); bw.write("helloWorld"); bw.newLine(); bw.close();使用上面两种方法把字符串写入csv文件中，文件都是空？
展开
收起
1
条回答
写回答
写回答
-
为了完美解决你的问题，特分享我自己的FileKit.java工具给你。
你只需要使用createFile方法，传入一行一个的List<String>对象就可以生成了，目录不存在这些都判断了，只要你的目录可写就行了。
import com.google.common.base.Throwables; import lombok.extern.slf4j.Slf4j; import java.io.*; import java.util.ArrayList; import java.util.List; /** * Created by jettykoo on 14-6-26 17:32. * Copyright (c) 2014, WeTeam Inc. All right reserved. * WeTeam PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. * TEAM Zebra * * @version v0.0.1 */ @Slf4j public enum FileKit { ice; /** * 遍历文件夹中文件 * * @param filepath 文件路径 * @return 返回file［］ 数组 */ public File[] getFileList(String filepath) { File d = null; File list[] = null; /** 建立当前目录中文件的File对象 **/ try { d = new File(filepath); if (d.exists()) { list = d.listFiles(); } } catch (Exception e) { log.debug("Other Exception", e); } /** 取得代表目录中所有文件的File对象数组 **/ return list; } /** * 读取文本文件内容 * * @param filePathAndName 带有完整绝对路径的文件名 * @param encoding 文本文件打开的编码方式 * @return 返回文本文件的内容 */ public String readTxt(String filePathAndName, String encoding) throws IOException { encoding = encoding.trim(); StringBuffer str = new StringBuffer(""); String st = ""; try { FileInputStream fs = new FileInputStream(filePathAndName); InputStreamReader isr; if (encoding.equals("")) { isr = new InputStreamReader(fs); } else { isr = new InputStreamReader(fs, encoding); } BufferedReader br = new BufferedReader(isr); try { String data = ""; while ((data = br.readLine()) != null) { str.append(data); } } catch (Exception e) { str.append(e.toString()); } st = str.toString(); if (st != null && st.length() > 1) st = st.substring(0, st.length() - 1); } catch (IOException es) { log.debug("IO Exception", es); st = ""; } return st; } /** * 读取文本文件内容 * * @param filePathAndName 带有完整绝对路径的文件名 * @param encoding 文本文件打开的编码方式 * @return 返回文本文件的内容 */ public List<String> readTxtList(String filePathAndName, String encoding) throws IOException { encoding = encoding.trim(); List<String> listStr = new ArrayList<>(); try { FileInputStream fs = new FileInputStream(filePathAndName); InputStreamReader isr; if (encoding.equals("")) { isr = new InputStreamReader(fs); } else { isr = new InputStreamReader(fs, encoding); } BufferedReader br = new BufferedReader(isr); try { String data = ""; while ((data = br.readLine()) != null) { listStr.add(data); } } catch (Exception e) { listStr.add(e.toString()); } } catch (IOException es) { log.debug("IO Exception", es); } return listStr; } /** * 新建目录 * * @param folderPath 目录 * @return 返回目录创建后的路径 */ public Boolean createFolder(String folderPath) { String dir = folderPath; boolean bool = true; try { File myFilePath = new File(dir); if (!myFilePath.exists()) { bool = myFilePath.mkdirs(); } } catch (Exception e) { bool = false; log.debug("Other Exception", e); } return bool; } /** * 新建文件 * * @param filePathAndName 文本文件完整绝对路径及文件名 * @return */ public Boolean createFile(String filePathAndName) { boolean bool = true; try { File myFileAndName = new File(filePathAndName); if (!myFileAndName.exists()) { bool = myFileAndName.createNewFile(); } } catch (IOException e) { bool = false; log.debug("IOException", e); } catch (Exception e) { bool = false; log.debug("Other Exception", e); } finally { return bool; } } /** * 新建文件，并写入内容 * * @param filePath 文本文件完整绝对路径 * @param fileName 文件名 * @param fileContent 文本文件内容 * @return */ public Boolean createFile(String filePath, String fileName, String fileContent) { boolean bool = false; try { filePath = filePath.toString(); fileName = fileName.toString(); if (!filePath.endsWith("/")) { filePath += "/"; } String filePathAndName = filePath + fileName; if (createFolder(filePath) && createFile(filePathAndName)) { File myFilePath = new File(filePathAndName); FileWriter resultFile = new FileWriter(myFilePath); PrintWriter myFile = new PrintWriter(resultFile); String strContent = fileContent; myFile.println(strContent); myFile.close(); resultFile.close(); bool = true; } } catch (IOException e) { log.debug("IO Exception", e); } catch (Exception e) { log.debug("Other Exception", e); } finally { return bool; } } /** * 新建文件，并写入内容 * * @param filePath 文本文件完整绝对路径 * @param fileName 文件名 * @param fileContentList 文本文件内容集合 * @return */ public Boolean createFile(String filePath, String fileName, List<String> fileContentList) { boolean bool = false; try { filePath = filePath.toString(); fileName = fileName.toString(); if (!filePath.endsWith("/")) { filePath += "/"; } String filePathAndName = filePath + fileName; if (createFolder(filePath) && createFile(filePathAndName)) { File myFilePath = new File(filePathAndName); FileWriter resultFile = new FileWriter(myFilePath); PrintWriter myFile = new PrintWriter(resultFile); for (String strContent : fileContentList) { myFile.println(strContent); } myFile.close(); resultFile.close(); bool = true; } } catch (IOException e) { log.debug("IO Exception", e); } catch (Exception e) { log.debug("Other Exception", e); } finally { return bool; } } /** * 有编码方式的文件创建和内容写入 * * @param filePath 文本文件完整绝对路径 * @param fileName 文件名 * @param fileContent 文本文件内容 * @param encoding 编码方式 例如 GBK 或者 UTF-8 * @return */ public Boolean createFile(String filePath, String fileName, String fileContent, String encoding) { boolean bool = false; try { filePath = filePath.toString(); fileName = fileName.toString(); if (!filePath.endsWith("/")) { filePath += "/"; } String filePathAndName = filePath + fileName; if (createFolder(filePath) && createFile(filePathAndName)) { File myFilePath = new File(filePathAndName); PrintWriter myFile = new PrintWriter(myFilePath, encoding); String strContent = fileContent; myFile.println(strContent); myFile.close(); bool = true; } } catch (IOException e) { log.debug("IO Exception", e); } catch (Exception e) { log.debug("Other Exception", e); } finally { return bool; } } /** * 删除文件 * * @param filePathAndName 文本文件完整绝对路径及文件名 * @return Boolean 成功删除返回true遭遇异常返回false */ public Boolean delFile(String filePathAndName) { boolean bea = false; try { String filePath = filePathAndName; File myDelFile = new File(filePath); if (myDelFile.exists()) { myDelFile.delete(); bea = true; } else { bea = false; } } catch (Exception e) { log.debug("Other Exception", e); } return bea; } /** * 删除文件 * * @param folderPath 文件夹完整绝对路径 * @return */ public void delFolder(String folderPath) { try { /**删除完里面所有内容**/ delAllFile(folderPath); String filePath = folderPath; filePath = filePath.toString(); File myFilePath = new File(filePath); /**删除空文件夹**/ myFilePath.delete(); } catch (Exception e) { log.debug("Other Exception", e); } } /** * 删除指定文件夹下所有文件 * * @param path 文件夹完整绝对路径 * @return */ public Boolean delAllFile(String path) { boolean bea = false; File file = new File(path); if (!file.exists()) { return bea; } if (!file.isDirectory()) { return bea; } String[] tempList = file.list(); File temp = null; for (int i = 0; i < tempList.length; i++) { if (path.endsWith(File.separator)) { temp = new File(path + tempList[i]); } else { temp = new File(path + File.separator + tempList[i]); } if (temp.isFile()) { temp.delete(); } if (temp.isDirectory()) { /**先删除文件夹里面的文件**/ delAllFile(path + "/" + tempList[i]); /**再删除空文件**/ delFolder(path + "/" + tempList[i]); bea = true; } } return bea; } /** * 复制单个文件 * * @param oldPathFile 准备复制的文件源 * @param newPathFile 拷贝到新绝对路径带文件名 * @return */ public void copyFile(String oldPathFile, String newPathFile) { try { int bytesum = 0; int byteread = 0; File oldfile = new File(oldPathFile); if (oldfile.exists()) { InputStream inStream = new FileInputStream(oldPathFile); FileOutputStream fs = new FileOutputStream(newPathFile); byte[] buffer = new byte[1444]; while ((byteread = inStream.read(buffer)) != -1) { bytesum += byteread; fs.write(buffer, 0, byteread); } inStream.close(); } } catch (IOException e) { log.debug("IO Exception", e); } catch (Exception e) { log.debug("Other Exception", e); } } /** * 复制整个文件夹的内容 * * @param oldPath 准备拷贝的目录 * @param newPath 指定绝对路径的新目录 * @return */ public void copyFolder(String oldPath, String newPath) { try { /**如果文件夹不存在 则建立新文件**/ new File(newPath).mkdirs(); File a = new File(oldPath); String[] file = a.list(); File temp = null; for (int i = 0; i < file.length; i++) { if (oldPath.endsWith(File.separator)) { temp = new File(oldPath + file[i]); } else { temp = new File(oldPath + File.separator + file[i]); } if (temp.isFile()) { FileInputStream input = new FileInputStream(temp); FileOutputStream output = new FileOutputStream(newPath + "/" + (temp.getName()).toString()); byte[] b = new byte[1024 * 5]; int len; while ((len = input.read(b)) != -1) { output.write(b, 0, len); } output.flush(); output.close(); input.close(); } /**如果是子文件**/ if (temp.isDirectory()) { copyFolder(oldPath + "/" + file[i], newPath + "/" + file[i]); } } } catch (IOException e) { log.debug("IO Exception", e); } catch (Exception e) { log.debug("Other Exception", e); } } /** * 移动文件 * * @param oldPath * @param newPath * @return */ public void moveFile(String oldPath, String newPath) { copyFile(oldPath, newPath); delFile(oldPath); } /** * 移动目录 * * @param oldPath * @param newPath * @return */ public void moveFolder(String oldPath, String newPath) { copyFolder(oldPath, newPath); delFolder(oldPath); } /** * 取得文件后缀名 * * @param filename * @return */ public String getExtensionName(String filename) { if ((filename != null) && (filename.length() > 0)) { int dot = filename.lastIndexOf('.'); if ((dot > -1) && (dot < (filename.length() - 1))) { return filename.substring(dot + 1); } } return filename; } /** * 截取文件后缀名 * * @param filename * @return */ public String getFileNameNoExt(String filename) { if ((filename != null) && (filename.length() > 0)) { int dot = filename.lastIndexOf('.'); if ((dot > -1) && (dot < (filename.length()))) { return filename.substring(0, dot); } } return filename; } /** * 截取文件名 * * @param filename * @return */ public String getPathNoFileName(String filename) { if ((filename != null) && (filename.length() > 0)) { int dot = filename.lastIndexOf('/'); if ((dot > -1) && (dot < (filename.length()))) { return filename.substring(0, dot); } } return filename; } /** * 建立一个可以追加的BufferedReader * * @param fileDir * @param fileName * @return */ public BufferedWriter getWriter(String fileDir, String fileName) { try { File f1 = new File(fileDir); if (!f1.exists()) { f1.mkdirs(); } f1 = new File(fileDir, fileName); if (!f1.exists()) { f1.createNewFile(); } BufferedWriter bw = new BufferedWriter(new FileWriter(f1.getPath(), true)); return bw; } catch (IOException e) { log.debug("IO Exception", e); return null; } catch (Exception e) { log.debug("Other Exception", e); return null; } } /** * 得到一个BufferedReader * * @param fileDir * @param fileName * @param encoding * @return */ public BufferedReader getReader(String fileDir, String fileName, String encoding) { try { File file = new File(fileDir, fileName); InputStreamReader read = new InputStreamReader(new FileInputStream( file), encoding); BufferedReader br = new BufferedReader(read); return br; } catch (FileNotFoundException ex) { log.debug("File Exception", ex); return null; } catch (IOException e) { log.debug("IO Exception", e); return null; } catch (Exception e) { log.debug("Other Exception", e); return null; } } }
######Throwables和Slf4j的两个jar包能提供下吗？万分感谢！######其实是，编译后文件放在classes文件夹下了，写进去了得，不过还是谢谢你了######
说到底，csv不过也是txt文本文件，只是后缀名是csv，直接当成写入txt就行了，一行一个，字段之间用逗号分隔。So easy!
######回复 @还不让重名啊 :
<slf4j.version>1.7.12</slf4j.version> <logback.version>1.1.3</logback.version> <lombok.version>1.16.6</lombok.version>
<!-- Logs --> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-api</artifactId> <version>${slf4j.version}</version> </dependency> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-classic</artifactId> <version>${logback.version}</version> </dependency> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-core</artifactId> <version>${logback.version}</version> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>${lombok.version}</version> <scope>provided</scope> </dependency>
######
引用来自“LarryKoo”的评论
为了完美解决你的问题，特分享我自己的FileKit.java工具给你。
你只需要使用createFile方法，传入一行一个的List<String>对象就可以生成了，目录不存在这些都判断了，只要你的目录可写就行了。
import com.google.common.base.Throwables; import lombok.extern.slf4j.Slf4j; import java.io.*; import java.util.ArrayList; import java.util.List; /** * Created by jettykoo on 14-6-26 17:32. * Copyright (c) 2014, WeTeam Inc. All right reserved. * WeTeam PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. * TEAM Zebra * * @version v0.0.1 */ @Slf4j public enum FileKit { ice; /** * 遍历文件夹中文件 * * @param filepath 文件路径 * @return 返回file［］ 数组 */ public File[] getFileList(String filepath) { File d = null; File list[] = null; /** 建立当前目录中文件的File对象 **/ try { d = new File(filepath); if (d.exists()) { list = d.listFiles(); } } catch (Exception e) { log.debug("Other Exception", e); } /** 取得代表目录中所有文件的File对象数组 **/ return list; } /** * 读取文本文件内容 * * @param filePathAndName 带有完整绝对路径的文件名 * @param encoding 文本文件打开的编码方式 * @return 返回文本文件的内容 */ public String readTxt(String filePathAndName, String encoding) throws IOException { encoding = encoding.trim(); StringBuffer str = new StringBuffer(""); String st = ""; try { FileInputStream fs = new FileInputStream(filePathAndName); InputStreamReader isr; if (encoding.equals("")) { isr = new InputStreamReader(fs); } else { isr = new InputStreamReader(fs, encoding); } BufferedReader br = new BufferedReader(isr); try { String data = ""; while ((data = br.readLine()) != null) { str.append(data); } } catch (Exception e) { str.append(e.toString()); } st = str.toString(); if (st != null && st.length() > 1) st = st.substring(0, st.length() - 1); } catch (IOException es) { log.debug("IO Exception", es); st = ""; } return st; } /** * 读取文本文件内容 * * @param filePathAndName 带有完整绝对路径的文件名 * @param encoding 文本文件打开的编码方式 * @return 返回文本文件的内容 */ public List<String> readTxtList(String filePathAndName, String encoding) throws IOException { encoding = encoding.trim(); List<String> listStr = new ArrayList<>(); try { FileInputStream fs = new FileInputStream(filePathAndName); InputStreamReader isr; if (encoding.equals("")) { isr = new InputStreamReader(fs); } else { isr = new InputStreamReader(fs, encoding); } BufferedReader br = new BufferedReader(isr); try { String data = ""; while ((data = br.readLine()) != null) { listStr.add(data); } } catch (Exception e) { listStr.add(e.toString()); } } catch (IOException es) { log.debug("IO Exception", es); } return listStr; } /** * 新建目录 * * @param folderPath 目录 * @return 返回目录创建后的路径 */ public Boolean createFolder(String folderPath) { String dir = folderPath; boolean bool = true; try { File myFilePath = new File(dir); if (!myFilePath.exists()) { bool = myFilePath.mkdirs(); } } catch (Exception e) { bool = false; log.debug("Other Exception", e); } return bool; } /** * 新建文件 * * @param filePathAndName 文本文件完整绝对路径及文件名 * @return */ public Boolean createFile(String filePathAndName) { boolean bool = true; try { File myFileAndName = new File(filePathAndName); if (!myFileAndName.exists()) { bool = myFileAndName.createNewFile(); } } catch (IOException e) { bool = false; log.debug("IOException", e); } catch (Exception e) { bool = false; log.debug("Other Exception", e); } finally { return bool; } } /** * 新建文件，并写入内容 * * @param filePath 文本文件完整绝对路径 * @param fileName 文件名 * @param fileContent 文本文件内容 * @return */ public Boolean createFile(String filePath, String fileName, String fileContent) { boolean bool = false; try { filePath = filePath.toString(); fileName = fileName.toString(); if (!filePath.endsWith("/")) { filePath += "/"; } String filePathAndName = filePath + fileName; if (createFolder(filePath) && createFile(filePathAndName)) { File myFilePath = new File(filePathAndName); FileWriter resultFile = new FileWriter(myFilePath); PrintWriter myFile = new PrintWriter(resultFile); String strContent = fileContent; myFile.println(strContent); myFile.close(); resultFile.close(); bool = true; } } catch (IOException e) { log.debug("IO Exception", e); } catch (Exception e) { log.debug("Other Exception", e); } finally { return bool; } } /** * 新建文件，并写入内容 * * @param filePath 文本文件完整绝对路径 * @param fileName 文件名 * @param fileContentList 文本文件内容集合 * @return */ public Boolean createFile(String filePath, String fileName, List<String> fileContentList) { boolean bool = false; try { filePath = filePath.toString(); fileName = fileName.toString(); if (!filePath.endsWith("/")) { filePath += "/"; } String filePathAndName = filePath + fileName; if (createFolder(filePath) && createFile(filePathAndName)) { File myFilePath = new File(filePathAndName); FileWriter resultFile = new FileWriter(myFilePath); PrintWriter myFile = new PrintWriter(resultFile); for (String strContent : fileContentList) { myFile.println(strContent); } myFile.close(); resultFile.close(); bool = true; } } catch (IOException e) { log.debug("IO Exception", e); } catch (Exception e) { log.debug("Other Exception", e); } finally { return bool; } } /** * 有编码方式的文件创建和内容写入 * * @param filePath 文本文件完整绝对路径 * @param fileName 文件名 * @param fileContent 文本文件内容 * @param encoding 编码方式 例如 GBK 或者 UTF-8 * @return */ public Boolean createFile(String filePath, String fileName, String fileContent, String encoding) { boolean bool = false; try { filePath = filePath.toString(); fileName = fileName.toString(); if (!filePath.endsWith("/")) { filePath += "/"; } String filePathAndName = filePath + fileName; if (createFolder(filePath) && createFile(filePathAndName)) { File myFilePath = new File(filePathAndName); PrintWriter myFile = new PrintWriter(myFilePath, encoding); String strContent = fileContent; myFile.println(strContent); myFile.close(); bool = true; } } catch (IOException e) { log.debug("IO Exception", e); } catch (Exception e) { log.debug("Other Exception", e); } finally { return bool; } } /** * 删除文件 * * @param filePathAndName 文本文件完整绝对路径及文件名 * @return Boolean 成功删除返回true遭遇异常返回false */ public Boolean delFile(String filePathAndName) { boolean bea = false; try { String filePath = filePathAndName; File myDelFile = new File(filePath); if (myDelFile.exists()) { myDelFile.delete(); bea = true; } else { bea = false; } } catch (Exception e) { log.debug("Other Exception", e); } return bea; } /** * 删除文件 * * @param folderPath 文件夹完整绝对路径 * @return */ public void delFolder(String folderPath) { try { /**删除完里面所有内容**/ delAllFile(folderPath); String filePath = folderPath; filePath = filePath.toString(); File myFilePath = new File(filePath); /**删除空文件夹**/ myFilePath.delete(); } catch (Exception e) { log.debug("Other Exception", e); } } /** * 删除指定文件夹下所有文件 * * @param path 文件夹完整绝对路径 * @return */ public Boolean delAllFile(String path) { boolean bea = false; File file = new File(path); if (!file.exists()) { return bea; } if (!file.isDirectory()) { return bea; } String[] tempList = file.list(); File temp = null; for (int i = 0; i < tempList.length; i++) { if (path.endsWith(File.separator)) { temp = new File(path + tempList[i]); } else { temp = new File(path + File.separator + tempList[i]); } if (temp.isFile()) { temp.delete(); } if (temp.isDirectory()) { /**先删除文件夹里面的文件**/ delAllFile(path + "/" + tempList[i]); /**再删除空文件**/ delFolder(path + "/" + tempList[i]); bea = true; } } return bea; } /** * 复制单个文件 * * @param oldPathFile 准备复制的文件源 * @param newPathFile 拷贝到新绝对路径带文件名 * @return */ public void copyFile(String oldPathFile, String newPathFile) { try { int bytesum = 0; int byteread = 0; File oldfile = new File(oldPathFile); if (oldfile.exists()) { InputStream inStream = new FileInputStream(oldPathFile); FileOutputStream fs = new FileOutputStream(newPathFile); byte[] buffer = new byte[1444]; while ((byteread = inStream.read(buffer)) != -1) { bytesum += byteread; fs.write(buffer, 0, byteread); } inStream.close(); } } catch (IOException e) { log.debug("IO Exception", e); } catch (Exception e) { log.debug("Other Exception", e); } } /** * 复制整个文件夹的内容 * * @param oldPath 准备拷贝的目录 * @param newPath 指定绝对路径的新目录 * @return */ public void copyFolder(String oldPath, String newPath) { try { /**如果文件夹不存在 则建立新文件**/ new File(newPath).mkdirs(); File a = new File(oldPath); String[] file = a.list(); File temp = null; for (int i = 0; i < file.length; i++) { if (oldPath.endsWith(File.separator)) { temp = new File(oldPath + file[i]); } else { temp = new File(oldPath + File.separator + file[i]); } if (temp.isFile()) { FileInputStream input = new FileInputStream(temp); FileOutputStream output = new FileOutputStream(newPath + "/" + (temp.getName()).toString()); byte[] b = new byte[1024 * 5]; int len; while ((len = input.read(b)) != -1) { output.write(b, 0, len); } output.flush(); output.close(); input.close(); } /**如果是子文件**/ if (temp.isDirectory()) { copyFolder(oldPath + "/" + file[i], newPath + "/" + file[i]); } } } catch (IOException e) { log.debug("IO Exception", e); } catch (Exception e) { log.debug("Other Exception", e); } } /** * 移动文件 * * @param oldPath * @param newPath * @return */ public void moveFile(String oldPath, String newPath) { copyFile(oldPath, newPath); delFile(oldPath); } /** * 移动目录 * * @param oldPath * @param newPath * @return */ public void moveFolder(String oldPath, String newPath) { copyFolder(oldPath, newPath); delFolder(oldPath); } /** * 取得文件后缀名 * * @param filename * @return */ public String getExtensionName(String filename) { if ((filename != null) && (filename.length() > 0)) { int dot = filename.lastIndexOf('.'); if ((dot > -1) && (dot < (filename.length() - 1))) { return filename.substring(dot + 1); } } return filename; } /** * 截取文件后缀名 * * @param filename * @return */ public String getFileNameNoExt(String filename) { if ((filename != null) && (filename.length() > 0)) { in2020-06-09 23:09:06赞同 展开评论 打赏
版权声明：本文内容由阿里云实名注册用户自发贡献，版权归原作者所有，阿里云开发者社区不拥有其著作权，亦不承担相应法律责任。具体规则请查看《阿里云开发者社区用户服务协议》和《阿里云开发者社区知识产权保护指引》。如果您发现本社区中有涉嫌抄袭的内容，填写侵权投诉表单进行举报，一经查实，本社区将立刻删除涉嫌侵权内容。
相关问答
