Question

在JAVA中如何①利用字符流读写一个指定文本文件。②利用读写器类实现对指定文本的读写。

Answer 1

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

public class ReaderAndWriter {

/**
*
* @param path 完整路径 如 c:\test.txt
* @param charset 字符集，若为null采用平台默认字符集
* @throws IOException
*/
public void read(String path, String charset) throws IOException {

BufferedReader reader=null;
InputStreamReader isr=null;
try {
if(null!=charset){
isr=new InputStreamReader(new FileInputStream(path),charset);
}else{
isr=new InputStreamReader(new FileInputStream(path));
}
reader=new BufferedReader(isr);
String tmp=reader.readLine();
while(null!=tmp){
System.out.println(tmp);
tmp=reader.readLine();
}
} finally{
if(null!=reader){
reader.close();
}
}

}

/**
*
* @param path 文件绝对路径 如 c:\test.txt，若文件存在，则覆盖内容
* @param content 要写入文件的内容
* @param charset 字符集，若为null,则采用平台默认字符集
* @throws IOException
*/
public void write(String path, String content, String charset)
throws IOException {
FileOutputStream fos = new FileOutputStream(path);
OutputStreamWriter writer = null;
try {
if (null != charset) {
writer = new OutputStreamWriter(fos, charset);
} else {
writer = new OutputStreamWriter(fos);
}
writer.append(content);
} finally {
if (null != writer) {
writer.flush();
writer.close();
}
}
}

}

Answer 2

用字符流读取文件： URL指的是文件路径
BufferedReader read=new BufferedReader(new FileReader(url));
read.readLine() 按行读取文本文件

写文件： URL指的是文件路径
BufferedWriter writer=new BufferedWriter(new FileWriter(url),true);
writer.append(str) 向指定文件追加内容，str指要追加的内容
writer.flush(); 记得最后刷新，把Writer的内容写到文件中