JAVA-文件合并

package com.testSplitByNumber;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;

import com.csvreader.CsvReader;

public class CombineFile {
    public static List<Integer> list = new ArrayList<Integer>();/*存放有序的分割文件标号*/
    public static List<File> list2 = new ArrayList<File>(); /*存放有序的分割文件*/
    public static String name = null;
    public static String path = "F:/zh";
    public static void main(String args[]){
        File file = new File(path);
        if(! file.exists() || !file.isDirectory()){
            System.out.println("文件夹错误!");
        }else{
            long start = System.currentTimeMillis();
            File files[] = file.listFiles();
            list = fileNum(files);
            fileOrder(list);
            fileName(list, list2);
            
            BufferedWriter bw = null;
            CsvReader reader = null;
            try {
                bw = new BufferedWriter(new FileWriter(new File("F:/zzh03.csv")));
                int num = 0;
                /*对每一个文件进行处理*/
                for(int i = 0;i < list2.size();i++){
                    File f = list2.get(i);
                    reader = new CsvReader(f.getPath(),',',Charset.forName("GBK"));
                    reader.setSafetySwitch(false);
                    while(reader.readRecord()){
                        num++;
                        String string[] = reader.getValues();
                        bw.write(writeLine(string)+"\r\n");
                        if(num % 100000 == 0){
                            bw.flush();
                            System.out.println("合并文件" + num + "行");
                        }
                    }
                }
                long end = System.currentTimeMillis();
                System.out.println("合并完成，共用时"+(end-start)/1000+"s");
            } catch (IOException e1) {
                e1.printStackTrace();
            }finally{
                if(reader != null){
                    reader.close();
                    reader = null;
                }
                try {
                    bw.flush();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    /**
     *对csv中的每一行处理 
     */
    public static String writeLine(String strs[]){
        StringBuffer sb = new StringBuffer("");
        for(int i = 0;i < strs.length;i++){
            sb.append(strs[i]+",");
        }
        return sb.substring(0, sb.length() - 1).toString();
    }
    
    /**截取文件标号并存入list*/
    public static List<Integer> fileNum(File files[]){
        for(int i = 0;i < files.length;i++){
            name = files[i].getName().substring(0, files[i].getName().lastIndexOf(".")-1);
            String  n = files[i].getName().substring(files[i].getName().length()-5, files[i].getName().length()-4);
            list.add(Integer.parseInt(n));    
        }
        return list;
    }
    
    /**对文件标号排序*/
    public static List<Integer> fileOrder(List<Integer> list){
        for(int i = 0;i < list.size()-1;i++){
            for(int j = 1;j < list.size() - i;j++){
                int temp = 0;
                if(list.get(j - 1) .compareTo(list.get(j))>0){
                    temp = list.get(j - 1);
                    list.set((j - 1),list.get(j ));
                    list.set(j , temp);        
                }
            }
        }
        return list;
    }
    
    /**将list对应标号的对应文件放入list2*/
    public static List<File> fileName(List<Integer> list,List<File> list2){
        for(int i = 0;i < list.size();i++ ){
            File file2 = new File(path+"/"+name + list.get(i)+".csv");
            list2.add(file2);
        }
        return list2;
    }
}