import static org.junit.Assert.*;

 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileReader;
 import java.io.FileWriter;
 import java.io.IOException;

 import org.junit.Test;

 import com.sun.org.apache.bcel.internal.generic.NEW;

 public class MyTest {
     //通过字符流写入数据到指定的文件中
     @Test
     public void testWrite() throws IOException {
         String path = "F:"+File.separator+"demo.txt";
         FileReader fileReader = null;
         try {
             fileReader = new FileReader(path);
             char[] buf = new char[10];
             int temp =0;
 //            fileReader去读取10个字符，并且将读取到的字符放到buf数组里面，实际督导多少个字符的个数存在temp中
             while((temp = fileReader.read(buf))!=-1){
                 System.out.println(new String(buf,0,temp));
             }

         } catch (FileNotFoundException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }

     }

 }

char[] buf = new char[100];