求大神！！！如何把ArrayList集合写入txt文件

如何把ArrayList集合写入txt文件 谢谢！！！急用！！！

 import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.util.ArrayList;

public class ArrayToTxt {
    public static void main(String[] args) throws Exception{
        File f=new File("d:/1.txt");
        ArrayList<String> al=new ArrayList<String>();
        al.add("first");
        al.add("second");
        al.add("third");
        BufferedWriter bw=new BufferedWriter(new FileWriter(f));
        for(int i=0;i<al.size();i++){
            bw.write(al.get(i));
            bw.newLine();
        }
        bw.close();
    }
}

缓冲字符（BufferedWriter ）是一个字符流类来处理字符数据。不同于字节流（数据转换成字节），你可以直接写字符串，数组或集合保存到文件。
复制代码 代码如下:

package com.yiibai.iofile;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;

public class WriteToFileExample {
public static void main(String[] args) {
try {

String content = "This is the content to write into file";

File file = new File("/users/mkyong/filename.txt");

// if file doesnt exists, then create it
if (!file.exists()) {
file.createNewFile();
}

FileWriter fw = new FileWriter(file.getAbsoluteFile());
BufferedWriter bw = new BufferedWriter(fw);
bw.write(content);
bw.close();

System.out.println("Done");

} catch (IOException e) {
e.printStackTrace();
}
}
}

循环输出，加特殊标记（如换行符）区分对象

看看我这个文章，java向文件写入数据的3种方式。
http://blog.csdn.net/wgw335363240/article/details/5678965

public class Test {
public static void main(String[] args) throws IOException {
List list=new ArrayList();
for (int i = 0; i < 10; i++) {
list.add(i);//集合中放入0-9
}
//下面是写文件
boolean flag = false;
FileWriter fw = null;
BufferedWriter bw = null;
try {
fw = new FileWriter("d:/test.txt", true);
bw = new BufferedWriter(fw, 100);
for (Integer integer : list) {
bw.write(integer+"");
}

flag = true;
} catch (IOException e) {
System.out.println("写入文件出错");
flag = false;
} finally {
if (bw != null) {
bw.flush();
bw.close();
}
if (fw != null)
fw.close();
}
}
}