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;
}
}