java IO 读取数据

java IO 读取数据

提供集中读取数据的方法

package com.viashare.read;

import org.omg.CORBA.PRIVATE_MEMBER;

import java.io.*;

/**
 * Created by Jeffy on 16/5/17.
 */
public class ReadMain {

    private static final String READ_PATH = "/Users/jeffy-pc/Downloads/test.txt";
    private static final String WRITE_PATH = "/Users/jeffy-pc/Downloads/test2.txt";

    public static void main(String[] args) throws IOException {
//        bufferRead();
//        ByteReader();
        randomRead();
    }

    private static final void bufferRead() throws IOException {
        BufferedReader input = new BufferedReader(new FileReader(READ_PATH));
        StringBuffer sb = new StringBuffer();
        String line = "";
        while((line = input.readLine())!=null){
            sb.append(line);
        }
        if(input != null){
            input.close();
        }
        System.err.println(sb.toString());
    }

    private static final void ByteReader() throws IOException {
        File file = new File(READ_PATH);
        InputStream in = new FileInputStream(file);
        System.err.println(convertStreamToString(in));
        in.close();
    }

    static String convertStreamToString(java.io.InputStream is) {
        java.util.Scanner s = new java.util.Scanner(is).useDelimiter("\\A");
        return s.hasNext() ? s.next() : "";
    }

    private static final  void randomRead() throws IOException {
        RandomAccessFile randomAccessFile = new RandomAccessFile(READ_PATH,"r");
        long length = randomAccessFile.length();
        randomAccessFile.seek(0);
        byte[] bytes = new byte[1024];
        int readByte = 0;
        while((readByte = randomAccessFile.read(bytes)) != -1){
            System.out.write(bytes, 0, readByte);
        }
        if(null != randomAccessFile){
            randomAccessFile.close();
        }

    }
}

java7 读取文件的API

import java.io.BufferedWriter;
import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.file.*;
import java.util.List;

/**
 * Created by jeffy on 2016/05/17.
 */
public class QuickReadAndWrite {

    public static void main(String[] a) throws IOException {
        Path path= Paths.get("/Users/xieqiang/test.txt");
        try(
            //如果文件存在则直接打开，否则创建文件    
            BufferedWriter writer=Files.newBufferedWriter(path,Charset.forName("utf-8"));

            //可以指定打开文件的模式，这里表示追加文件
            //BufferedWriter writer=Files.newBufferedWriter(path,Charset.forName("utf-8"),StandardOpenOption.APPEND);
        ) {
            writer.write("hello,java7,我是不迷失");
            writer.newLine();
            writer.write("test");
            System.out.println("ok");
        }


        List<String> lines= Files.readAllLines(path);
        System.out.println(lines);
    }
}

    private static final void readAndCopy() throws URISyntaxException, IOException {
        Files.lines(Paths.get(READ_PATH), StandardCharsets.UTF_8).forEach(System.out::println);
        BufferedWriter writer = Files.newBufferedWriter(Paths.get(WRITE_PATH), StandardCharsets.UTF_8);
        writer.write(new String(Files.readAllBytes(Paths.get(READ_PATH))));
        writer.flush();
    }