java io學習（二十一） FileReader和FileWriter

FileReader和FileWriter源碼分析

1. FileReader 源碼(基於jdk1.7.40)

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));
    }
}

從中，我們可以看出FileReader是基於InputStreamReader實現的。

2. FileWriter 源碼(基於jdk1.7.40)

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));
    }
}

從中，我們可以看出FileWriter是基於OutputStreamWriter實現的。

示例程序

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 測試程序
 *
 * @author skywang
 */
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 演示函數
     *
     */
    private static void testWrite() {
        try {
            // 創建文件“file.txt”對應File對象
            File file = new File(FileName);
            // 創建FileOutputStream對應FileWriter：將字節流轉換為字符流，即寫入out1的數據會自動由字節轉換為字符。
			// 查看本欄目
c1=字
buf=流示例0123456
來源：http://www.cnblogs.com/skywang12345/p/io_22.html