用ByteArrayIn/OutputStream内存流大写字符串转小写

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;


/**
 * 大写字符串用内存流转小写的两种方法
 * @author ddmcc
 *
 */


public class ByteArrayTest{

public static void main(String[] args) throws IOException{
test1();
}

public static void test1() throws IOException{

String str = "ABCDEF";

ByteArrayOutputStream daos = new ByteArrayOutputStream();  //创建输出流

DataOutputStream dops = new DataOutputStream(daos); //创建输出数据流

dops.writeUTF(str.toLowerCase());//写入变成小写后的字符串

ByteArrayInputStream dais = new ByteArrayInputStream(daos.toByteArray()); //把输出流字节数组当成数据源

DataInputStream dips = new DataInputStream(dais);//输入数据流

System.out.println(dips.readUTF());//读取数组内容

dips.close();

dops.close();
}

public static void test2() throws IOException{

String str = "ABCDEF";

ByteArrayInputStream dis = new ByteArrayInputStream(str.getBytes()); //字符串转成字节数组

ByteArrayOutputStream dos = new ByteArrayOutputStream();

int len = 0;

while((len = dis.read()) != -1){  //读取数组中内容

char ch = (char)len;          //int数据转成char

dos.write(Character.toLowerCase(ch)); //写入转成小写的字符
}
System.out.println(dos.toString());  //得到字符串
dos.close();
dis.close();
}
}