java在文件中写入字符串代码怎么写

用file类新建一个文件 然后在这个文件里面写入字符串

    String str = "test";//写入到字符串
    ByteArrayInputStream bis = new ByteArrayInputStream(str.getBytes("UTF-8"));
    FileOutputStream fos = new FileOutputStream(new File("D:/txt","文件名.txt"));//输出路径和文件名
    byte[] b = new byte[1024];
    int len;
    while((len=bis.read(b, 0, b.length))!=-1){
        fos.write(b, 0, len);
    }
    fos.flush();
    fos.close();
    bis.close();

示例文件名为Program.java，其代码如下：

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;

public class Program {
    public static void main(String[] args) throws IOException {

        String[] array = new String[3];
        array[0] = "int i = 1, j = 2;";
        array[1] = "i++;";
        array[2] = "j = i+1;";

        // Create our BufferedWriter.
        BufferedWriter writer = new BufferedWriter(new FileWriter(
                "D:\\output.txt"));

        // Loop over the elements in the string array and write each line.
        for (String line : array) {
            writer.write(line);
            writer.newLine();
        }
        writer.close();
    }
}

package com.exercise;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;

public class Demo {
public static void main(String[] args) throws IOException {
String s = "ksjdvniiladvfn";//准备写入文件的字符串

    BufferedWriter bw = new BufferedWriter(new FileWriter("f://a.txt"));//创建高效字符流并关联文件
    bw.write(s);//直接写入字符串

    bw.close();
}

}