java中有好几种读写文件的方法，但是个人觉得最简单的还是FileInputStream、FileOutputStream类，示例代码：
package jmyang.file;
import java.io.*;
public class FileTest {
/*
* 删除文件
*/
public static boolean delete(String fileName){
boolean result = false;
File f = new File(fileName);
if (f.exists()){
try{
result = f.delete();
}
catch(Exception e){
e.printStackTrace();
}
}
else{
result = true;
}
return result;
}
/*
* 读取文件
*/
public static String read(String fileName) {
File f = new File(fileName);
if (!f.exists()) {
return "File not found!";
}
FileInputStream fs;
String result = null;
try {
fs = new FileInputStream(f);
byte[] b = new byte[fs.available()];
fs.read(b);
fs.close();
result = new String(b);
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
/*
*写文件
*/
public static boolean write(String fileName, String fileContent) {
boolean result = false;
File f = new File(fileName);
try {
FileOutputStream fs = new FileOutputStream(f);
byte[] b = fileContent.getBytes();
fs.write(b);
fs.flush();
fs.close();
result = true;
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
/*
* 追加内容到文件
*/
public static boolean append(String fileName, String fileContent) {
boolean result = false;
File f = new File(fileName);
try {
if (f.exists()) {
FileInputStream fsIn = new FileInputStream(f);
byte[] bIn = new byte[fsIn.available()];
fsIn.read(bIn);
String oldFileContent = new String(bIn);
//System.out.println("旧内容:" + oldFileContent);
fsIn.close();
if (!oldFileContent.equalsIgnoreCase("")) {
fileContent = oldFileContent + "\r\n" + fileContent;
//System.out.println("新内容:" + fileContent);
}
}
FileOutputStream fs = new FileOutputStream(f);
byte[] b = fileContent.getBytes();
fs.write(b);
fs.flush();
fs.close();
result = true;
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
}
调用示例：
//FileTest f = new FileTest();
//System.out.println(f.read("c:/a.txt"));
final String fileName = "c:/a.txt";
System.out.println(FileTest.delete(fileName));
//System.out.println(FileTest.append(fileName,"这是java写入的内容1"));
//System.out.println(FileTest.append(fileName,"这是java写入的内容2"));
