按行写入文件内容如下:
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.TreeSet;
public class writeFile {
public void fileWriter(String fileName,TreeSet<String> clist) throws IOException{ //创建一个FileWriter对象
FileWriter fw = new FileWriter(fileName); //遍历clist集合写入到fileName中
for (String str: clist){
fw.write(str);
fw.write("\n");
} //刷新缓冲区
fw.flush(); //关闭文件流对象
fw.close();
}
public TreeSet<String> readFileByLines(String fileName) throws IOException{
File file = new File(fileName);
BufferedReader reader = new BufferedReader(new FileReader(file));
String tempString = null; //创建一个集合
TreeSet<String> nums = new TreeSet<String>(); //按行读取文件内容,并存放到集合
while ((tempString = reader.readLine()) != null){
nums.add(tempString);
}
reader.close(); //返回集合变量
return nums;
}
public static void main(String[] args) throws IOException{ //创建writeFile对象wf
writeFile wf = new writeFile(); //读取文件内容保存到一个集合对象中
TreeSet<String> ts = wf.readFileByLines("F:/A_remain.txt"); //将集合对象ts的内容保存到text.txt文件中
wf.fileWriter("F:/text.txt", ts);
}
}
A_remain.txt文件内容如下:
BGP-HK-1-3TQ
CCN-BJ-7-351
CCN-BJ-7-353
CCN-BJ-7-356
CCN-BJ-7-358
CCN-BJ-H-381
CCN-BJ-H-382
CCN-BJ-H-3F1
CER-BJ-3-33C
CER-BJ-3-355
CER-BJ-3-356
CER-BJ-3-357
执行程序后,text.txt文件的内容如下:
BGP-HK-1-3TQ
CCN-BJ-7-351
CCN-BJ-7-353
CCN-BJ-7-356
CCN-BJ-7-358
CCN-BJ-H-381
CCN-BJ-H-382
CCN-BJ-H-3F1
CER-BJ-3-33C
CER-BJ-3-355
CER-BJ-3-356
CER-BJ-3-357