import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.RandomAccessFile;

/**
 *
 * @author malik
 * @version 2011-3-10 下午10:49:41
 */
public class AppendFile {

    public static void method1(String file, String conent) {   
        BufferedWriter out = null;   
        try {   
            out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file, true)));   
            out.write(conent);   
        } catch (Exception e) {   
            e.printStackTrace();   
        } finally {   
            try {   
                if(out != null){
                    out.close();   
                }
            } catch (IOException e) {   
                e.printStackTrace();   
            }   
        }   
    }   

    /**  
     * 追加文件：使用FileWriter  
     *   
     * @param fileName  
     * @param content  
     */  
    public static void method2(String fileName, String content) { 
        FileWriter writer = null;
        try {   
            // 打开一个写文件器，构造函数中的第二个参数true表示以追加形式写文件   
            writer = new FileWriter(fileName, true);   
            writer.write(content);     
        } catch (IOException e) {   
            e.printStackTrace();   
        } finally {   
            try {   
                if(writer != null){
                    writer.close();   
                }
            } catch (IOException e) {   
                e.printStackTrace();   
            }   
        } 
    }   

    /**  
     * 追加文件：使用RandomAccessFile  
     *   
     * @param fileName 文件名  
     * @param content 追加的内容  
     */  
    public static void method3(String fileName, String content) { 
        RandomAccessFile randomFile = null;
        try {   
            // 打开一个随机访问文件流，按读写方式   
            randomFile = new RandomAccessFile(fileName, "rw");   
            // 文件长度，字节数   
            long fileLength = randomFile.length();   
            // 将写文件指针移到文件尾。   
            randomFile.seek(fileLength);   
            randomFile.writeBytes(content);    
        } catch (IOException e) {   
            e.printStackTrace();   
        } finally{
            if(randomFile != null){
                try {
                    randomFile.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }  

    public static void main(String[] args) {
        try{
            File file = new File("d://text.txt");
            if(file.createNewFile()){
                System.out.println("Create file successed");
            }
            method1("d://text.txt", "123");
            method2("d://text.txt", "123");
            method3("d://text.txt", "123");
        }catch(Exception e){
            System.out.println(e);
        }
    }
}

转载于：http://blog.csdn.net/malik76/article/details/6408726/