Java中如何生成csv文件并以SOH分隔符分隔 csv java

COMMA SEPARATED VALUE的缩写，出现在档案总管中的档案类型是「逗号分格」，依计算机原来的设定，如果直接点选该档案，计算机将以EXCEL的模式开启该档案。但建议您千万不要这么做，因为CSV档如果以EXCEL开启，由于计算机档案数据转换的原因，会将其CRC之数值改做科学记号方式储存，而造成档案中的 CRC值发生错误。这也是笔者初出茅庐时所得到的惨痛经验，但如果想一窥CSV档的真实面貌，笔者建议您使用WORDPAD或是记事本（NOTE）来开启，再则先另存新档后用EXCEL开启，也是方法之一。
开启后的CSV档包含了四或五个字段（部分），由左至右分别记载着：文件名称（XXXX.JPG）、档案大小（以BYTE为单位）、CRC32值（八个英文字母或数字组成）、
档案路径（档案储存的子目录名称）和档案内容描述（一般来说都是明星的英文姓名甚或是专辑名称，也可能空白）。而其中第四栏「档案路径」因为每个人储存整理图档的方式不同，所以本栏通常不存在，而一般有含有「档案路径」这栏的CSV档，又称为ECSV档案 CSV文件，也叫逗号分隔值文件，英文名称COMMA SEPARATED VALUE

具体文件格式

每条记录占一行
以逗号为分隔符
逗号前后的空格会被忽略
字段中包含有逗号，该字段必须用双引号括起来
字段中包含有换行符，该字段必须用双引号括起来
字段前后包含有空格，该字段必须用双引号括起来
字段中的双引号用两个双引号表示
字段中如果有双引号，该字段必须用双引号括起来
第一条记录，可以是字段名


我们经常将Excel格式的文件保存为csv格式以方便上传和修改，可是当数据中包含逗号和双引号的时候Excel会把该字段用双引号括住并把数据中的"改为""，从而给解析带来了困难。我写了以下函数来解析这样的字符串：

testSplitCSV.java: 


import java.util.Vector; 

class testSplitCSV{ 

 /** 

 * Split one line of csv file 

 * @return a String array results 

 */ 

 public static String[] splitCSV(String src) throws Exception{ 

 if (src==null || src.equals("")) return new String[0]; 

 StringBuffer st=new StringBuffer(); 

 Vector result=new Vector(); 

 boolean beginWithQuote = false; 

 for (int i=0;i<src.length();i++){ 

 char ch = src.charAt(i); 

 if (ch=='\"'){ 

 if (beginWithQuote){ 

 i++; 

 if (i>=src.length()){ 

 result.addElement(st.toString()); 

 st=new StringBuffer(); 

 beginWithQuote=false; 

 }else{ 

 ch=src.charAt(i); 

 if (ch == '\"'){ 

 st.append(ch); 

 }else if (ch == ','){ 

 result.addElement(st.toString()); 

 st=new StringBuffer(); 

 beginWithQuote = false; 

 }else{ 

 throw new Exception("Single double-quote char mustn't exist in filed "+(result.size()+1)+" while it is begined with quote\nchar at:"+i); 

 } 

 } 

 }else if (st.length()==0){ 

 beginWithQuote = true; 

 }else{ 

 throw new Exception("Quote cannot exist in a filed which doesn't begin with quote!\nfield:"+(result.size()+1)); 

 } 

 }else if (ch==','){ 

 if (beginWithQuote){ 

 st.append(ch); 

 }else{ 

 result.addElement(st.toString()); 

 st=new StringBuffer(); 

 beginWithQuote = false; 

 } 

 }else{ 

 st.append(ch); 

 } 

 } 

 if (st.length()!=0){ 

 if (beginWithQuote){ 

 throw new Exception("last field is begin with but not end with double quote"); 

 }else{ 

 result.addElement(st.toString()); 

 } 

 } 

 String rs[] = new String[result.size()]; 

 for (int i=0;i<rs.length;i++){ 

 rs[i]=(String)result.elementAt(i); 

 } 

 return rs; 

 } 


 public static void main(String[] args){ 

 String src1= "\"fh,zg\",sdf,\"asfs,\",\",dsdf\",\"aadf\"\"\",\"\"\"hdfg\",\"fgh\"\"dgnh\",hgfg'dfh,\"asdfa\"\"\"\"\",\"\"\"\"\"fgjhg\",\"gfhg\"\"\"\"hb\""; 

 try { 

 String[] Ret = splitCSV(src1); 

 for (int i=0;i<Ret.length;i++){ 

 System.out.println(i+": "+Ret[i]); 

 } 

 } 

 catch(Exception e) { 

 e.printStackTrace(); 

 } 

 } 

} 



/** 

* 在很多时候我们都需要将一些数据集合以某种文件格式输出,其中CSV文件输出是一种比较常用的方式. 

* 下面是一个简单的实现CSV文件输出的代码,与大家共享. 

*/ 

import org.apache.struts.action.ActionMapping; 

import org.apache.struts.action.ActionForm; 

import javax.servlet.http.HttpServletRequest; 

import javax.servlet.http.HttpServletResponse; 

import org.apache.struts.action.ActionForward; 

import org.apache.struts.actions.DispatchAction; 

import java.io.PrintWriter; 

import javax.servlet.http.HttpSession; 



public class CsvUtil extends DispatchAction { 


public ActionForward exportCsv(ActionMapping mapping, ActionForm form, 

 HttpServletRequest request, HttpServletResponse response) 

 throws Exception { 


 HttpSession session = request.getSession(); 

 //头部 

 String data = "姓名,电子邮件地址,移动电话,业务电话,业务传真,职务,部门\n"; 

 //具体的数据,可以动态的从数据库中读取 

 data += "张三,[e-mail],13800000000,010-88889999,010-99998888,部门领导,产品研发部\n"; 

 data += "李四,[e-mail],13800000001,010-88889999,010-99998888,业务助理,产品研发部\n"; 

 StringBuilder str = new StringBuilder(); 

 str.append(data); 

 response.setContentType("text/csv"); 

 response.setCharacterEncoding("gb18030"); 

 response 

 .setHeader("Content-Disposition", 

 "attachment; filename=\"" 

 + new String("通讯薄.csv".getBytes("gb18030"), 

 "iso8859-1") + "\""); 

 PrintWriter out = response.getWriter(); 

 out.write(str.toString()); 

 out.flush(); 

 out.close(); 

 return null; 

} 


} 



import java.io.File; 

import java.io.FileReader; 

import java.io.FileWriter; 

import java.io.IOException; 

import java.io.StringReader; 

import java.util.List; 


import au.com.bytecode.opencsv.CSVReader; 

import au.com.bytecode.opencsv.CSVWriter; 

import au.com.bytecode.opencsv.bean.ColumnPositionMappingStrategy; 

import au.com.bytecode.opencsv.bean.CsvToBean; 


public class CsvDemo { 


 public static void main(String[] args) throws IOException { 


 final String[] header = new String[]{"name", "sex", "age"}; 

 final String[][] data = new String[][]{header, {"Lucy", "F", "22"}, {"Tom", "M", "25"}, {"Lily", "F", "19"}}; 


 File tempFile = File.createTempFile("csvWriterTest", ".csv"); 

 tempFile.deleteOnExit(); 


 CSVWriter writer = new CSVWriter(new FileWriter(tempFile)); 

 for (int i = 0; i < data.length; i++) { 

 writer.writeNext(data[i]); 

 } 

 writer.close(); 


 CSVReader reader = new CSVReader(new FileReader(tempFile)); 

 String[] line; 

 String readline = ""; 

 for (int row = 0; (line = reader.readNext()) != null; row++) { 

 for (int col = 0; col < line.length; col++) { 

 if (data[row][col] != null) { 

 System.out.print(line[col] + (col != line.length - 1 ? "," : "")); 

 readline = readline + line[col] + (col != line.length - 1 ? "," : " "); 

 } 

 } 

 System.out.println(""); 

 } 


 ColumnPositionMappingStrategy strat = new ColumnPositionMappingStrategy(); 

 strat.setType(Person.class); 

 String[] columns = new String[] {"name", "sex", "age"}; 

 strat.setColumnMapping(columns); 

 CsvToBean csv = new CsvToBean(); 

 List<?> persons = csv.parse(strat, new StringReader(readline)); 

 for (int i = 1; i < persons.size(); i++) { 

 System.out.println(((Person)persons.get(i)).getName()); 

 System.out.println(((Person)persons.get(i)).getSex()); 

 System.out.println(((Person)persons.get(i)).getAge()); 

 } 


 reader.close(); 

 } 

}