stream流批量读取并合并文件

import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.StringWriter;
import java.nio.channels.FileChannel;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.apache.commons.io.FileUtils;
import org.apache.commons.lang.StringUtils;

import com.ist.common.properties.SysConfig;

/**
 * 文件合并
 *
 *
 *
 */
public class ServerTemplate extends Template {
    /** 跨平台的换行符  */
    public static final String LINE_SEPARATOR = System.getProperty("line.separator");

    /**
     * 合并文件
     * @Method       mergeFiles
     * @Author       lbh
     * @Date         2014-12-11 下午02:59:54
     * @param outFile 路径+输出文件名
     * @param files 输入文件列表
     */
    public boolean mergeFiles(String outFile, List<String> files) {

        boolean mergeResult = true;
        FileChannel fileOutChannel = null; //声明通道
        FileReader fileReader = null;
        BufferedReader bufferedReader = null ;

        try{
            if(files == null || files.size() < 1){
            logger.info("Make sure there have outnumber 2 files ");
            //System.out.println("Make sure there have outnumber 2 files ");
            mergeResult = false;
            }
            else if(files.size() == 1){//只有一个文件，那么只要改名即可
                File file = new File(files.get(0).toString());
                file.renameTo(new File(outFile));
            }
            else{
                fileOutChannel = new FileOutputStream(outFile).getChannel(); //实例化输出通道,此时将

创建文件。

                //循环所有文件
                /*Iterator it = fileMap.keySet().iterator();
                int i = 0; //计数
                while(it.hasNext()){*/
                for(int i=0; i<files.size();i++){
                    //System.out.println(files.get(i));
                    File file = new File(files.get(i).toString());
                    if(!file.exists()){//容错检查
                        logger.info("Make sure every file is existed");
                        //System.out.println("file:"+ files.get(i) +" is not existed");
                    }
                    fileReader = new FileReader(file);

                    if(!fileReader.ready()){//容错检查
                        logger.info("Make sure every file is existed");
                        //System.out.println("file "+ files.get(i) +" is not already to

read");
                    }
                    bufferedReader = new BufferedReader(fileReader);
                    /*InputStreamReader inputStreamReader = new InputStreamReader(new

FileInputStream(files[i]),"UTF-8");//此为stream方式读文件，做备用。
                    BufferedReader bufferedReader = new BufferedReader(inputStreamReader);*/

                    //开始处理文件
                    if(bufferedReader != null){
                        if(i == 0){ //如果是首个文件，那么除去最后一行保留前两行再写入
                            mergeResult = handleFile("fist", bufferedReader, outFile);
                        }
                        else if(i == files.size() - 1){ //如果是最后一个文件，那么去除前两行

，保留最后一行
                            mergeResult = handleFile("last", bufferedReader, outFile);
                        }
                        else{ //其他则同时去除前两行和最后一行
                            mergeResult = handleFile("normal", bufferedReader, outFile);
                        }
                        //System.out.println("file:"+ files.get(i) +" merge sate is --

"+mergeResult);
                        //logger.info("file:"+files.get(i)+" merge sate is --

"+mergeResult);
                    }

                    //删除该文件
                    file.delete();
                }
            }
            } catch (IOException e){
                e.printStackTrace();
                return mergeResult;
            }

            //关闭

            if(fileOutChannel !=null){
                try{bufferedReader.close();}catch (IOException ignore) {return mergeResult;}
            }
            if(fileReader !=null){
                try{fileReader.close();}catch (IOException ignore) {return mergeResult;}
            }
            if(bufferedReader !=null){
                try{bufferedReader.close();}catch (IOException ignore) {return mergeResult;}
            }

        return mergeResult;

    }

    /**
     * 处理单个文件，读取后立即写入， type:fist--首个文件；last--末个文件；以及其他文件
     * @Method       handleFile
     * @Author       lbh
     * @Date         2014-12-11 上午09:49:19
     */
    public static boolean handleFile(String type, BufferedReader bufferedReader, String outFile){
        boolean handleResult = false; //是否成功
        FileWriter fileWriter = null;
        String readString = ""; //存放读取数据的变量
        String strA,strB,strC; //临时变量
        try{
            fileWriter = new FileWriter(outFile,true);
            if("fist".equals(type)){ //首文件的处理
                strA = "";
                strB = "";
                strC = "";
                int fistI = 0;//计数
                while((strC = bufferedReader.readLine()) != null){ //从第一行开始循环读
                    strA = strB;
                    strB = strC;
                    readString = strA + LINE_SEPARATOR;//最后一行的strB被丢弃
                    //输出
                    if(fistI > 0){//避免第一行空行
                        fileWriter.write(readString);
                    }
                    fistI ++;
                }
                handleResult = true;
            }
            if("last".equals(type)){ //末文件的处理
                strA = "";
                bufferedReader.readLine();
                bufferedReader.readLine(); //执行两次，已读取并丢弃了前两行。
                while((strA = bufferedReader.readLine()) != null){ //开始循环读
                    readString = strA + LINE_SEPARATOR;

                    //输出
                    fileWriter.write(readString);
                }
                handleResult = true;
            }
            else { //其他文件的处理
                strA = "";
                strB = "";
                strC = "";
                bufferedReader.readLine();
                bufferedReader.readLine(); //执行两次，已读取并丢弃了前两行。
                long i = 0;
                while((strC = bufferedReader.readLine()) != null){ //开始循环读
                    strA = strB;
                    strB = strC;
                    readString = strA + LINE_SEPARATOR;//最后一行的strB被丢弃

                    //输出
                    if(i > 0){//避免第一行空行
                        fileWriter.write(readString);
                    }
                    i ++;
                }
                handleResult = true;
            }
        }
        catch (IOException e) {
            e.printStackTrace();
            return handleResult;
        }
        finally{
            try{
                bufferedReader.close();
                fileWriter.close();
                }
            catch (IOException ignore) {return handleResult;}
        }

        return handleResult;
    }

    public static void main(String[] args) throws Exception{
        /*System.out.println("开始");
        List<String> ssss = new ArrayList<String>();
        ssss.add("E:\\111\\xmlTest\\a.xml");
        ssss.add("E:\\111\\xmlTest\\b.xml");
        ssss.add("E:\\111\\xmlTest\\c.xml");
        ServerTemplate st = new ServerTemplate();
        st.mergeFiles("E:\\111\\xmlTest\\stream2.xml", ssss);
        System.out.println("结束");*/
    }

}