Java PrintWriter无法正常工作 [英] Java PrintWriter not working
问题描述
$ b $ pre $ $ $ $ $ $
$ PrintWriter pW =新的PrintWriter(新的文件(fileName)); (int y = 0; y< 25; y ++)
{
($ x
$ pW.write(拼图[X] [Y]);
}
pW.println();
$ b catch(IOException e)
{
System.err.println(error is:+ e.getMessage());
$ / code $ / pre
Close你的PrintWriter在一个finally块中刷新它并回收资源
$ b $ pre $ public $ writeToFile(String fileName){
// ****注意pW必须在try块之前声明
PrintWriter pW = null;
尝试{
pW = new PrintWriter(new File(fileName)); (int x = 0; x <25; x ++){
for(int y = 0; y <25; y ++){
pW.write(puzzle [x] [Y]);
}
pW.println();
catch(IOException e){
// System.err.println(error is:+ e.getMessage());
e.printStackTrace(); // ***这是更多的信息***
}最后{
如果(pW!= null){
pW.close(); // ****关闭它刷新它并回收资源****
}
}
}
警告:代码没有经过测试也没有编译过。
注意另一个选项是使用尝试使用资源。
I am simply trying to write my 2d array "puzzle" to a file. I have a double for loop which reads through each of the 'char' values in my array and supposedly writes them to the file. I can't seem to find the error in my code. The file says it is modified when I run the program, but it is still blank. Thanks guys!
public void writeToFile(String fileName)
{
try{
PrintWriter pW = new PrintWriter(new File(fileName));
for(int x = 0; x < 25; x++)
{
for(int y = 0; y < 25; y++)
{
pW.write(puzzle[x][y]);
}
pW.println();
}
}
catch(IOException e)
{
System.err.println("error is: "+e.getMessage());
}
}
Close your PrintWriter in a finally block to flush it and to reclaim resources
public void writeToFile(String fileName) {
// **** Note that pW must be declared before the try block
PrintWriter pW = null;
try {
pW = new PrintWriter(new File(fileName));
for (int x = 0; x < 25; x++) {
for (int y = 0; y < 25; y++) {
pW.write(puzzle[x][y]);
}
pW.println();
}
} catch (IOException e) {
// System.err.println("error is: "+e.getMessage());
e.printStackTrace(); // *** this is more informative ***
} finally {
if (pW != null) {
pW.close(); // **** closing it flushes it and reclaims resources ****
}
}
}
Caveat: Code not tested nor compiled.
Note that another option is to use try with resources.
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