Java 如何在 Servlet 中读取文本文件和输出？
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How do I read text file and output in Servlet?
提问by olle
i have file: input.txt I want to read this file, put values in new output.txt from input.txt.
我有文件：input.txt 我想读取这个文件，将值从 input.txt 放入新的 output.txt 中。
Servlet.java
小程序
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/plain");
response.setHeader("Content-Disposition",
"attachment;filename=output.txt");
PrintWriter out = response.getWriter();
ServletContext cntxt = this.getServletContext();
String fName = "/input.txt";
InputStream ins = cntxt.getResourceAsStream(fName);
try {
if(ins != null){
InputStreamReader isr = new InputStreamReader(ins);
BufferedReader reader = new BufferedReader(isr);
int n = 0;
String word ="";
while((word= reader.readLine())!= null)
{
n = Integer.parseInt(word);
out.println(n);
}
} finally {
out.close();
}
}
but output.txt is empty. What's wrong?
但是 output.txt 是空的。怎么了？
回答by Shamse Alam
Try following code
试试下面的代码
input.txtshould be present in the root directory of your application
input.txt应该存在于应用程序的根目录中
protected void processRequest(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
response.setContentType("text/plain");
response.setHeader("Content-Disposition", "attachment;filename=output.txt");
PrintWriter out = response.getWriter();
ServletContext cntxt = this.getServletContext();
String fName = "/input.txt";
InputStream ins = cntxt.getResourceAsStream(fName);
try {
if (ins != null) {
InputStreamReader isr = new InputStreamReader(ins);
BufferedReader reader = new BufferedReader(isr);
int n = 0;
String word = "";
while ((word = reader.readLine()) != null) {
n = Integer.parseInt(word);
out.println(n);
}
}
}finally {
out.close();
}
}
回答by Jay
Apache FileUtils, could make it simple
Apache FileUtils，可以让它变得简单
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
PrintWriter out = response.getWriter();
List<String> lines = FileUtils.readLines(new File("file.txt), "UTF-8");
for (String line : lines) {
out.println(line);
}
}
