Java IOException - 流已关闭
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Java IOException - Stream Closed
提问by Scitech
I get "IOException: Stream Closed"when I run this program. The text contains many lines of data. Program should read each line, do necessary function and write the output to a new file. I am confused as to which writer should be closed first and where.
当我运行这个程序时，我得到“ IOException：Stream Closed”。文本包含多行数据。程序应该读取每一行，执行必要的功能并将输出写入新文件。我对应该首先关闭哪个作家以及在哪里关闭感到困惑。
import java.net.*;
import java.io.*;
public class URLReader {
public static void main(String[] args) throws Exception {
BufferedReader br = null;
try {
// change this value
FileInputStream fis = new FileInputStream("C:\Users\Rao\Desktop\test.txt");
br = new BufferedReader(new InputStreamReader(fis, "UTF-8"));
String sCurrentLine;
while ((sCurrentLine = br.readLine()) != null) {
processLine(sCurrentLine); //error
}
} finally {
if (br != null)
br.close();
}
}
public static void processLine(String line) throws IOException {
String prename = line.substring(22);
int siz= prename.indexOf(":");
String name = prename.substring(0, siz);
URL oracle = new URL("http://ip-api.com/json/"+name);
BufferedReader in = new BufferedReader(new InputStreamReader(oracle.openStream()));
String inputLine;
while ((inputLine = in.readLine()) != null) // error
// System.out.println(inputLine);
in.close();
String baby = (line + "\t" + inputLine);
try {
FileWriter writer = new FileWriter("C:\Users\Rao\Desktop\output.txt", true);
writer.write(baby);
writer.write("\r\n"); // write new line
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
The exception is as follows:
例外情况如下：
Exception in thread "main" java.io.IOException: Stream closed
at java.io.BufferedReader.ensureOpen(Unknown Source)
at java.io.BufferedReader.readLine(Unknown Source)
at java.io.BufferedReader.readLine(Unknown Source)
at URLReader.processLine(URLReader.java:31)
at URLReader.main(URLReader.java:13)
采纳答案by Jens
You close the input stream in your loop:
您关闭循环中的输入流：
while ((inputLine = in.readLine()) != null) // error
// System.out.println(inputLine);
in.close();
You should close the stream outside of the loop:
您应该关闭循环外的流：
while ((inputLine = in.readLine()) != null) // error
{
//dosomething
// System.out.println(inputLine);
}
in.close();
回答by morels
You should put a function call in the while loop, like:
您应该在 while 循环中放置一个函数调用，例如：
- a
System.out.println("Hi, I'm a row!");or - uncomment
System.out.println(inputLine);or - put a semicolon at the end of the while statement
- 一个
System.out.println("Hi, I'm a row!");或 - 取消注释
System.out.println(inputLine);或 - 在 while 语句的末尾放一个分号
in order to let it to execute properly.
为了让它正确执行。
The code as it is written executes (comments omitted):
编写的代码执行（省略注释）：
...
while ((inputLine = in.readLine()) != null)
in.close();
...
so the first cycle of the loop executes correctly and runs in.close(). Then the second cycle the call inputLine = in.readLine()fails because the stream is closed and then the exception is thrown.
所以循环的第一个循环正确执行并运行in.close()。然后第二个循环调用inputLine = in.readLine()失败，因为流关闭，然后抛出异常。
