Android Java 如何读写CSV格式文件

      CSV 文件是Excel 的标准文件格式，在开发过程中经常需要格式化输出数据。CSV 的格式非常简单，都是一行一行存储的，同一行不同列之间用逗号隔开。下面的代码即为输出CSV 格式文件。

package com.test.mytest;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import android.os.Environment;

public class MyTestClass1 {

    public static final String mComma = ",";
    private static StringBuilder mStringBuilder = null;
    private static String mFileName = null;

    public static void open() {
        String folderName = null;
        if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
            String path = Environment.getExternalStorageDirectory().getAbsolutePath();
            if (path != null) {
                folderName = path +"/CSV/";
            }
        }
        
        File fileRobo = new File(folderName);  
        if(!fileRobo.exists()){  
            fileRobo.mkdir();  
        }
        mFileName = folderName + "log.csv";
        mStringBuilder = new StringBuilder();
        mStringBuilder.append("column1");
        mStringBuilder.append(mComma);
        mStringBuilder.append("column2");
        mStringBuilder.append(mComma);
        mStringBuilder.append("column3");
        mStringBuilder.append("\n");
    }

    public static void writeCsv(String value1, String value2, String value3) {
        mStringBuilder.append(value1);
        mStringBuilder.append(mComma);
        mStringBuilder.append(value2);
        mStringBuilder.append(mComma);
        mStringBuilder.append(value3);
        mStringBuilder.append("\n");
    }

    public static void flush() {
        if (mFileName != null) {
            try {
                File file = new File(mFileName);
                FileOutputStream fos = new FileOutputStream(file, false);
                fos.write(mStringBuilder.toString().getBytes());
                fos.flush();
                fos.close();
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        } else {
            throw new RuntimeException("You should call open() before flush()");
        }
    }
}