java中打印txt文档内容的方法简介说明

1.获取 File对象
2.获取 FileOutputStream对象
3.获取 BufferedReader对象
4.获取 BufferedWriter对象

使用字节流和字符流

import java.io.File;

import java.io.FileOutputStream;

import java.io.FileWriter;

public class TextFileGenerator {

public static void main(String[] args) throws Exception {

method1();

method2();

}

private static void method1() throws Exception {

String txtContent = "Hello World!";

File file = new File("test1.txt");

FileWriter fw = new FileWriter(file);

fw.write(txtContent);

fw.close();

}

private static void method2() throws Exception {

String txtContent = "Hello World!";

File file = new File("test2.txt");

FileOutputStream fos = new FileOutputStream(file);

fos.write(txtContent.getBytes());

fos.close();

}

}

直接字符流读取

private void input(String fileName) throws IOException {

    try(BufferedReader reader = new BufferedReader(new FileReader(fileName))) {

        String line;

        while((line=reader.readLine()) != null) {

            System.out.println(line);

        }   

    }

}

private void output(String fileName, String content) throws IOException{

    try(BufferedWriter  writer = new BufferedWriter(new FileWriter(fileName))) {

        writer.write(content);

        writer.flush();

    }

}

输出数据到TXT文件中

package com.java265;

import java.awt.AWTException;

import java.awt.Dimension;

import java.awt.Rectangle;

import java.awt.Robot;

import java.awt.Toolkit;

import java.awt.image.BufferedImage;

import java.io.BufferedOutputStream;

import java.io.File;

import java.io.FileOutputStream;

import javax.imageio.ImageIO;

public class ReadColorTest {

/**

* 读取一张图片的RGB值

*

* @throws Exception

*/

public void getImagePixel(String image) throws Exception {

File fileCar = new File("D:\\car.txt");

FileOutputStream fos = new FileOutputStream(fileCar);

BufferedOutputStream bos = new BufferedOutputStream(fos);

int[] rgb = new int[3];

File file = new File(image);

BufferedImage bi = null;

try {

bi = ImageIO.read(file);

} catch (Exception e) {

e.printStackTrace();

}

int width = bi.getWidth();

int height = bi.getHeight();

int minx = bi.getMinX();

int miny = bi.getMinY();

System.out.println("width=" + width + ",height=" + height + ".");

bos.write(("width=" + width + ",height=" + height + ".\n").getBytes());

System.out.println("minx=" + minx + ",miniy=" + miny + ".");

bos.write(("minx=" + minx + ",miniy=" + miny + ".\n").getBytes());

for (int i = minx; i width; i++) {

for (int j = miny; j height; j++) {

int pixel = bi.getRGB(i, j); // 下面三行代码将一个数字转换为RGB数字

rgb[0] = (pixel 0xff0000) 16;

rgb[1] = (pixel 0xff00) 8;

rgb[2] = (pixel 0xff);

System.out.println("i=" + i + ",j=" + j + ":(" + rgb[0] + ","+ rgb[1] + "," + rgb[2] + ")");

bos.write(("i=" + i + ",j=" + j + ":(" + rgb[0] + ","+ rgb[1] + "," + rgb[2] + ")\n").getBytes());

}

}

}

/**

* 返回屏幕色彩值

*

* @param x

* @param y

* @return

* @throws AWTException

*/

public int getScreenPixel(int x, int y) throws AWTException { // 函数返回值为颜色的RGB值。

Robot rb = null; // java.awt.image包中的类，可以用来抓取屏幕，即截屏。

rb = new Robot();

Toolkit tk = Toolkit.getDefaultToolkit(); // 获取缺省工具包

Dimension di = tk.getScreenSize(); // 屏幕尺寸规格

System.out.println(di.width);

System.out.println(di.height);

Rectangle rec = new Rectangle(0, 0, di.width, di.height);

BufferedImage bi = rb.createScreenCapture(rec);

int pixelColor = bi.getRGB(x, y);

return 16777216 + pixelColor; // pixelColor的值为负，经过实践得出：加上颜色最大值就是实际颜色值。

}

/**

* @param args

*/

public static void main(String[] args) throws Exception {

int x = 0;

ReadColorTest rc = new ReadColorTest();

x = rc.getScreenPixel(100, 345);

System.out.println(x + " - ");

rc.getImagePixel("D:\\car.jpg");

}

}

数据输出到txt文件

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.PrintStream;

public class TestBaiduKnow {

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

FileOutputStream fs = new FileOutputStream(new File("D:\\text.txt"));

PrintStream p = new PrintStream(fs);

p.println(100);

p.close();

}

}