long型和double型数 怎么写进文档 和输出啊 顺便帮看看 我那char型和string型 做法对不

Question

import java.util.Scanner;
import java.io.*;public class basicType {
                 public static void main(String[] args){                                 int a=1;
long b=2;
                           double d=8.0;
char c='a';
String str="hello";
try{
File inputFile = new File("D:\\JAVA\\test.txt");
File outputFile = new File("D:\\JAVA\\test.txt");
FileReader in=new FileReader(inputFile);
FileWriter out=new FileWriter(outputFile);
                                    out.write(a);
//out.write(b);
                                     //out.write(d);
out.write(c);
out.write(str);
                                out.close();      //关闭此流，但先刷新它
System.out.println("已将信息写入test.txt");
                                    System.out.println("整型数值为"+in.read());
//System.out.println("长整型数值为"+);
                                    //System.out.println("double型数值为"+);
System.out.println("char为"+(char)in.read());
System.out.print("字符串为");
while(in.ready())             //
{
System.out.print((char)in.read());
}
   }catch(IOException e){
   System.err.println(e);
   }
}
}long型和double型数  怎么写进文档 和输出啊  顺便帮看看  我那char型和string型 做法对不

Answer 1

你想要在txt里面打开就显示long double的数值，还是就是能够写到文件呢？

Answer 2

如果你想要在txt里面直接显示出来的话，写入到文件可以这样实现用FileWriterpackage csdn.p38;import java.io.FileReader;import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.FileInputStream;
public class BasicType {
    public static void main(String[] args){        int a=1;
        long b=2;
        double d=8.0;
        char c='a';
        String str="hello";
        try{
            File outputFile = new File("D:\\JAVA\\test.txt");
            FileWriter out=new FileWriter(outputFile);
            out.write(a+"");
            out.write(b+"");
            out.write(d+"");
            out.write(c);
            out.write(str);
            out.close(); //关闭此流，但先刷新它        }catch(IOException e){
            System.err.println(e);
        }
    }
}

Answer 3

DataOutputStream这个可以写入基本数据类型

Answer 4

如果想要用程序读写的话，需要用过滤流DataInputStream和DataOutputStream完成，下面是代码实现import java.io.*;
public class BasicType {
    public static void main(String[] args){        int a=1;
        long b=2;
        double d=8.0;
        char c='a';
        String str="hello";
        try{
            File outputFile = new File("test.txt");
            FileOutputStream out=new FileOutputStream(outputFile);
            DataOutputStream dataOut=new DataOutputStream(out);
            dataOut.write(a);
            dataOut.writeLong(b);
            dataOut.writeDouble(d);
            dataOut.write(c);
            dataOut.writeUTF(str);
            dataOut.close(); //关闭此流，但先刷新它
            System.out.println("已将信息写入test.txt");
            File inputFile = new File("test.txt");            DataInputStream in=new DataInputStream(new FileInputStream(inputFile));
            System.out.println("整型数值为"+in.read());
            System.out.println("长整型数值为"+in.readLong());
            System.out.println("double型数值为"+in.readDouble());
            System.out.println("char为"+(char)in.read());
            System.out.print("字符串为"+in.readUTF());            in.close();
        }catch(IOException e){
            System.err.println(e);
        }
    }
}