Question

为什么java中使用printWriter无法写入到txt文档

PrintWriter pw = new PrintWriter(new FileReader("E://java work/zuoweiji.txt"));
pw.print(str);
pw.close();
总是说找不到符号，小生初学java，希望高手帮忙解答

Answer 1

import java.io.*;
import java.util.*;
public class TestPrintWriter {
public static void main(String[] args)throws IOException {
File file=new File("temp2.txt");
if(file.exists()){
System.out.println("File temp.txt already exists.");
System.exit(0);
}

PrintWriter output=new PrintWriter(new FileWriter(file));

for(int i=0;i<10;i++){
output.print((int)(Math.random()*100)+" ");
}

output.close();
BufferedReader input=new BufferedReader(new FileReader("temp2.txt"));

int total=0;
String line;
while((line=input.readLine())!=null){
StringTokenizer tokens=new StringTokenizer(line);
while(tokens.hasMoreTokens())
total+=Integer.parseInt(tokens.nextToken());
}

output=new PrintWriter(new FileWriter(file,true));
output.printf("\n\n");
output.printf("Total is %d ",total);
output.close();
}
}

运行后，temp2.txt的内容：
85 10 92 59 71 87 2 95 31 73
Total is 605

Answer 2

因为printWriter是输出流。。 需要的参数也应当是一个输出流 而你的FileReader是一个输入流。。所以参数不对 会异常

应当要这样：前提是有这个zuoweiji.txt存在
try
{
PrintWriter pw = new PrintWriter(new FileOutputStream("E://java work/zuoweiji.txt"));
pw.print(str);
pw.close();

}
catch(Exception e)
{

}