1.nio实现读取大文件，之后分批读取写入数据库

2.nio实现读取大文件，之后分批写入指定文件

package com.ally;

import java.io.File;


import java.io.RandomAccessFile;


import java.nio.ByteBuffer;


import java.nio.channels.FileChannel;


import java.sql.*;

/**
Created by admin on 2016/6/28.
1.nio分批读取sql文件并执行插入数据库
2.读取一个文件写入另外文件


*/


public class TestNio {


public static void main(String args[]) throws Exception {


System.err.println("begin");


long start = System.currentTimeMillis();


int _5M = 1024 * 1024 * 5;


File fin = new File("D:\drug_general_info.sql");


FileChannel fcin = new RandomAccessFile(fin, "r").getChannel();


ByteBuffer rBuffer = ByteBuffer.allocate(_5M);


//将文件读取执行到数据库


readFileByLine(_5M, fcin, rBuffer);
 //将文件读取并写入另外文件

 File fout = new File("D:\\mm.sql");

 FileChannel fcout = new RandomAccessFile(fout, "rws").getChannel();

 ByteBuffer wBuffer = ByteBuffer.allocateDirect(_5M);

 saveOtherFile( _5M,  fcin, rBuffer,  fcout,  wBuffer);

 System.err.print((System.currentTimeMillis() - start) / 1000);


}
/**
将一个文件内容写入另外一个
@param bufSize
@param fcin
@param rBuffer
@param fcout
@param wBuffer


*/


public static void saveOtherFile(int bufSize, FileChannel fcin,


ByteBuffer rBuffer, FileChannel fcout, ByteBuffer wBuffer){


Statement pst = null;


String enterStr = "\n";


try {


byte[] bs = new byte[bufSize];


StringBuilder strBuf = new StringBuilder("");


String tempString = null;


while (fcin.read(rBuffer) != -1) {


int rSize = rBuffer.position();


rBuffer.rewind();


rBuffer.get(bs);


rBuffer.clear();


tempString = new String(bs, 0, rSize);


int fromIndex = 0;


int endIndex = 0;


int i = 0;


while ((endIndex = tempString.indexOf(enterStr, fromIndex)) != -1) {


String line = tempString.substring(fromIndex, endIndex);


line = strBuf.toString() + line;


writeFileByLine(fcout, wBuffer, line);


strBuf.delete(0, strBuf.length());


fromIndex = endIndex + 1;
         }

     }

 } catch (Exception e) {

     e.printStackTrace();

 }


}
/**
读文件写入数据库
@param bufSize
@param fcin
@param rBuffer


*/


public static void readFileByLine(int bufSize, FileChannel fcin,


ByteBuffer rBuffer) {


Connection conn = null;


Statement pst = null;


String enterStr = "\n";


try {


byte[] bs = new byte[bufSize];


StringBuilder strBuf = new StringBuilder("");


String tempString = null;


Class.forName("com.mysql.jdbc.Driver");


conn = DriverManager.getConnection(


"jdbc:mysql://localhost:3306/doctor?useUnicode=true&characterEncoding=utf-8", "root", "root");


pst = conn.createStatement();


while (fcin.read(rBuffer) != -1) {
     int rSize = rBuffer.position();

     rBuffer.rewind();

     rBuffer.get(bs);

     rBuffer.clear();

     tempString = new String(bs, 0, rSize);

     int fromIndex = 0;

     int endIndex = 0;

     int i = 0;

     while ((endIndex = tempString.indexOf(enterStr, fromIndex)) != -1) {

         String line = tempString.substring(fromIndex, endIndex);

         line = strBuf.toString() + line;

         strBuf.delete(0, strBuf.length());

         fromIndex = endIndex + 1;

         pst.addBatch(line);

       /*  System.out.println("-----------------------");

         System.out.println(line);

         System.out.println("-----------------------");*/

         if (i % 100 == 0) {

             System.out.println("执行了：" + i);

             if (i == 2700) {

                 System.out.println("导了：" + i);

             }

             int[] flag = pst.executeBatch();

             System.out.println("结果：" + flag[0]);

         }

         i += 1;

     }

     // 执行批量更新

     pst.executeBatch();

     if (rSize > tempString.length()) {

         strBuf.append(tempString.substring(fromIndex,

                 tempString.length()));

     } else {

         strBuf.append(tempString.substring(fromIndex, rSize));

     }

     //  System.out.println(strBuf.toString());

 }


} catch (Exception e) {


e.printStackTrace();


} finally {


try {


if (pst != null) {


pst.close();


}


if (conn != null) {


conn.close();


}


} catch (SQLException e) {


e.printStackTrace();


}


}


}
public static void writeFileByLine(FileChannel fcout, ByteBuffer wBuffer,


String line) {


try {


fcout.write(wBuffer.wrap(line.getBytes()), fcout.size());


} catch (Exception e) {


e.printStackTrace();


}


}


}