Java读写CSV格式文件（opencsv）

使用opencsv(opencsv-2.3.jar)，下载地址：http://sourceforge.net/projects/opencsv/files/latest/download

一，读取CSV格式文件：

import java.io.File;
import java.io.FileReader;
import java.util.List;

import au.com.bytecode.opencsv.CSVReader;

public class ReadCSV {
	public static void main(String[] args) throws Exception {
		File file = new File("e:\\read.csv");
		FileReader fReader = new FileReader(file);
		CSVReader csvReader = new CSVReader(fReader);
		String[] strs = csvReader.readNext();
		if(strs != null && strs.length > 0){
			for(String str : strs)
				if(null != str && !str.equals(""))
					System.out.print(str + " , ");
			System.out.println("\n---------------");
		}
		List<String[]> list = csvReader.readAll();
		for(String[] ss : list){
			for(String s : ss)
				if(null != s && !s.equals(""))
					System.out.print(s + " , ");
			System.out.println();
		}
		csvReader.close();
	}
}

执行结果如下：

编号 , 姓名 , 备注 , 
---------------
1 , Li , 123456 , 
2 , Sean , 

CSVReader.close()方法本质上是关闭传入其中的FileReader：

private BufferedReader br;
    
public CSVReader(Reader reader, char separator, char quotechar, 
		char escape, int line, boolean strictQuotes, boolean ignoreLeadingWhiteSpace) {
	this.br = new BufferedReader(reader);
	this.parser = new CSVParser(separator, quotechar, escape, 
			strictQuotes, ignoreLeadingWhiteSpace);
	this.skipLines = line;
}

public void close() throws IOException{
	br.close();
}

当然分隔符可以不是默认的逗号，只需在创建CSVReader时指定其分隔符即可：

CSVReader csvReader = new CSVReader(fReader, ';');

二，写CSV格式文件：

import java.io.File;
import java.io.FileWriter;
import java.io.Writer;

import au.com.bytecode.opencsv.CSVWriter;

public class WriteCSV {
	public static void main(String[] args) throws Exception {
		File file = new File("e:\\write.csv");
		Writer writer = new FileWriter(file);
		CSVWriter csvWriter = new CSVWriter(writer, ',');
		String[] strs = {"abc" , "abc" , "abc"};
		csvWriter.writeNext(strs);
		csvWriter.close();
	}
}

执行结果如下：

CSVWrite的构造方法如下：

public static final char DEFAULT_QUOTE_CHARACTER = '"';
 
public CSVWriter(Writer writer, char separator) {
	this(writer, separator, DEFAULT_QUOTE_CHARACTER);
}

双引号被用作默认的引用符（具体什么意思不清楚）

修改一下CSVReader的初始化方式：

CSVWriter csvWriter = new CSVWriter(writer, ',' , '\\');

CSVReader中使用的是CSVParser中的静态变量：

public static final char DEFAULT_QUOTE_CHARACTER = '"';

public static final char DEFAULT_ESCAPE_CHARACTER = '\\';

但是在CSVWriter中：

public static final char DEFAULT_QUOTE_CHARACTER = '"';
   
public static final char DEFAULT_ESCAPE_CHARACTER = '"';

看来应该是作者的疏忽