• java nio传输中文乱码


    之前在项目组时,写银行接口时,老是不太明白大端和小端模式会带来什么影响,今儿有空,正好把它给弄明白了。

    代码如下,有详细的注释:

    package com.io;
    
    import java.io.DataOutputStream;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.nio.ByteBuffer;
    import java.nio.channels.FileChannel;
    import java.util.Arrays;
    
    public class IoOutput {
    
        public static void main(String[] args) {
            /**
             * 小端模式转化int
             */
            byte[] bytes = intToByteArray1(25105);
            System.out.println(Arrays.toString(bytes));
            System.out.println(new String(bytes));
            
            /**
             * DataOutputstream.writeint 来写入文件
             */
            writerFile();
            /**
             *  nio 来读入字节
             */
            readFile();
            
        }
        /**
         * nio高性能读取出字节数组
         * 经验证,是以小端模式存放于数组
         */
        public static void readFile(){
            try {
                FileInputStream input = new FileInputStream(new File("test.txt")) ;
                FileChannel channel = input.getChannel() ;
                long length = channel.size() ;
                ByteBuffer byteBuffer = ByteBuffer.allocate((int)length);
                
                channel.read(byteBuffer);
                byteBuffer.flip();
                byte[] bytes = byteBuffer.array() ;
                byteBuffer.clear();
                channel.close();
                input.close();
                
                int index = 0;
                int size = bytesHighFirstToInt(bytes, index);
                index += 4;
                System.out.println((char)size);
                //System.out.println(Arrays.toString(bytes));
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            
        }
        /**
         * 将字符“我”转化为整数,写入文件
         * 经查,以小端模式写入文件
         */
        public static void writerFile(){
            try {
                DataOutputStream output = new DataOutputStream(new FileOutputStream("test.txt"));
                char c = '我' ;
                int i = c ;
                output.writeInt(i);
                output.flush();
                output.close();
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        /**
         * 按小端转化
         * @param i
         * @return
         */
        public static byte[] intToByteArray1(int i) {
            byte[] result = new byte[4];
            result[0] = (byte) ((i >> 24) & 0xFF);
            result[1] = (byte) ((i >> 16) & 0xFF);
            result[2] = (byte) ((i >> 8) & 0xFF);
            result[3] = (byte) (i & 0xFF);
            return result;
        }
        
        /**
         * 字节数组和整型的转换,大端转化,适用于读取writeInt的数据
         *
         * @param bytes 字节数组
         * @return 整型
         */
        public static int bytesHighFirstToInt(byte[] bytes, int start)
        {
            int num = bytes[start + 3] & 0xFF;
            num |= ((bytes[start + 2] << 8) & 0xFF00);
            num |= ((bytes[start + 1] << 16) & 0xFF0000);
            num |= ((bytes[start] << 24) & 0xFF000000);
            return num;
        }
    }
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  • 原文地址:https://www.cnblogs.com/xinzhuangzi/p/4290490.html
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