java文件路径的判断

文件的创建和读写

//read TXT file
class HotClickFile{
public void TxtReader(){
        String filepath = "D:\\java_test\\lucene\\data\\searchdata\\HotClick1.txt"; // 绝对路径或相对路径都可以，这里是绝对路径，写入文件时演示相对路径
File file = new File(filepath); // 要读取以上路径的HotClick.txt文件
if (!file.exists()) {//判断文件目录的存在
System.out.println("文件不存在！");
            System.exit(0);
        }
try { // 防止文件建立或读取失败，用catch捕捉错误并打印，也可以throw
            /* 读入TXT文件 */
FileInputStream fileInputStream = null;
            fileInputStream = new FileInputStream(file);
            InputStreamReader reader = new InputStreamReader(fileInputStream); // 建立一个输入流对象reader
BufferedReader br = new BufferedReader(reader); // 建立一个对象
String line = "";
            line = br.readLine();
            String []lines = null;
            Vector<String[]> hotclick = new Vector<String[]>();
while (line != null) {
                lines = line.split("；");
                hotclick.add(lines);
                line = br.readLine(); // 一次读入一行数据
}
/* 写入Txt文件 */
String fpath = "D:\\java_test\\lucene\\data\\searchdata\\output2.txt";
            File writein = new File(fpath);
if(!writein.exists())
            {
try {
                    writein.createNewFile();
                } catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
                }
            }
            BufferedWriter out = new BufferedWriter(new FileWriter(writein));
for(String[] str:hotclick){
                out.write(str[0]+" "+str[1]+" "+str[2]+"\n"); // \r\n即为换行
}
            out.flush(); // 把缓存区内容压入文件
out.close(); // 最后记得关闭文件
} catch (FileNotFoundException e) {
            e.printStackTrace();
        }catch (IOException e){
            e.printStackTrace();
        }
    }

}