此类从InputStreamReader类继承， FileReader用于读取字符流。
此类具有多个构造函数来创建所需的对象。以下是FileReader类提供的构造函数的列表。
| Sr.No. | Constructor & Remark |
|---|---|
| 1 |
FileReader(File file) 给定要读取的文件，此构造函数创建一个新的FileReader。 |
| 2 |
FileReader(FileDescriptor fd) 给定要读取的FileDescriptor，此构造函数创建一个新的FileReader。 |
| 3 |
FileReader(String fileName) 给定要读取的文件的名称，此构造函数创建一个新的FileReader。 |
拥有FileReader对象后，便会出现一系列可用于处理文件的辅助方法。
| Sr.No. | Method & Remark |
|---|---|
| 1 |
public int read() throws IOException 读取单个字符。返回一个int，它表示读取的字符。 |
| 2 |
public int read(char [] c，int offset，int len) 将字符读入数组。返回读取的字符数。 |
import java.io.*;
public class FileRead {
public static void main(String args[])throws IOException {
File file = new File("Hello1.txt");
</span><span class="com">//创建文件</span><span class="pln">
file</span><span class="pun">.</span><span class="pln">createNewFile</span><span class="pun">();</span><span class="pln">
</span><span class="com">//创建一个 FileWriter 对象</span><span class="pln">
</span><span class="typ">FileWriter</span><span class="pln"> writer </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">FileWriter</span><span class="pun">(</span><span class="pln">file</span><span class="pun">);</span><span class="pln">
</span><span class="com">//将内容写入文件</span><span class="pln">
writer</span><span class="pun">.</span><span class="pln">write</span><span class="pun">(</span><span class="str">"This\n is\n an\n example\n"</span><span class="pun">);</span><span class="pln">
writer</span><span class="pun">.</span><span class="pln">flush</span><span class="pun">();</span><span class="pln">
writer</span><span class="pun">.</span><span class="pln">close</span><span class="pun">();</span><span class="pln">
</span><span class="com">//创建一个 FileReader 对象</span><span class="pln">
</span><span class="typ">FileReader</span><span class="pln"> fr </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">FileReader</span><span class="pun">(</span><span class="pln">file</span><span class="pun">);</span><span class="pln">
</span><span class="kwd">char</span><span class="pln"> </span><span class="pun">[]</span><span class="pln"> a </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="kwd">char</span><span class="pun">[</span><span class="lit">50</span><span class="pun">];</span><span class="pln">
fr</span><span class="pun">.</span><span class="pln">read</span><span class="pun">(</span><span class="pln">a</span><span class="pun">);</span><span class="pln"> </span><span class="com">//将内容读取到数组</span><span class="pln">
</span><span class="kwd">for</span><span class="pun">(</span><span class="kwd">char</span><span class="pln"> c </span><span class="pun">:</span><span class="pln"> a</span><span class="pun">)</span><span class="pln">
</span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="kwd">print</span><span class="pun">(</span><span class="pln">c</span><span class="pun">);</span><span class="pln"> </span><span class="com">//一个一个地打印字符</span><span class="pln">
fr</span><span class="pun">.</span><span class="pln">close</span><span class="pun">();</span><span class="pln">
}
}
这将产生以下输出-
This is an example
