Java 中的FileReader和FileWriter源码分析_动力节点Java学院整理

  package java.io; public class FileReader extends InputStreamReader {   public FileReader(String fileName) throws FileNotFoundException {     super(new FileInputStream(fil java io系列21之 InputStreamReader和OutputStreamWritereName));   }   public FileReader(File file) throws FileNotFoundException {     super(new FileInputStream(file));   }   public FileReader(FileDescriptor fd) {     super(new FileInputStream(fd));   } }

 package java.io; public class FileWriter extends OutputStreamWriter {   public FileWriter(String fileName) throws IOException {     super(new FileOutputStream(fileName));   }   public FileWriter(String fileName, boolean append) throws IOException {     super(new FileOutputStream(fileName, append));   }   public FileWriter(File file) throws IOException {     super(new FileOutputStream(file));   }   public FileWriter(File file, boolean append) throws IOException {     super(new FileOutputStream(file, append));   }   public FileWriter(FileDescriptor fd) {     super(new FileOutputStream(fd));   } } 

import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.FileWriter;; import java.io.FileReader; import java.io.IOException; /**  * FileReader 和 FileWriter 测试程序 * *  */ public class FileReaderWriterTest {   private static final String FileName = "file.txt";   private static final String CharsetName = "utf-8";   public static void main(String[] args) {     testWrite();     testRead();   }   /**   * OutputStreamWriter 演示函数   *   */   private static void testWrite() {     try {       // 创建文件“file.txt”对应File对象       File file = new File(FileName);       // 创建FileOutputStream对应FileWriter：将字节流转换为字符流，即写入out的数据会自动由字节转换为字符。       FileWriter out = new FileWriter(file);      // 写入10个汉字       out1.write("字节流转为字符流示例");      // 向“文件中”写入"0123456789"+换行符      out1.write("0123456789/n");      out1.close();     } catch(IOException e) {       e.printStackTrace();     }   }   /**   * InputStreamReader 演示程序   */   private static void testRead() {     try {      // 方法1：新建FileInputStream对象       // 新建文件“file.txt”对应File对象       File file = new File(FileName);       FileReader in1 = new FileReader(file);       // 测试read()，从中读取一个字符      char c1 = (char)in1.read();       System.out.println("c1="+c1);       // 测试skip(long byteCount)，跳过4个字符       in1.skip(6);       // 测试read(char[] cbuf, int off, int len)       char[] buf = new char[10];       in1.read(buf, 0, buf.length);       System.out.println("buf="+(new String(buf)));       in.close();     } catch(IOException e) {       e.printStackTrace();     }   } }