【Java】PrintStream和PrintWriter

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活动地址：CSDN21天学习挑战赛

实例

package com;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.PrintStream;

public class PrintWriter_ {
    public static void main(String[] args) throws IOException {
        PrintStream out = System.out;
        //在默认情况下，PrintStream 输出数据的位置是 标准输出，即显示器
        
        out.print("john, hello");
        //因为print底层使用的是write , 所以我们可以直接调用write进行打印/输出
        out.write("Demo龙,你好".getBytes());
        out.close();

        //我们可以去修改打印流输出的位置/设备
        //1. 输出修改成到 "e:\f1.txt"
        //2. "hello, 韩顺平教育~" 就会输出到 e:f1.txt
        //3. public static void setOut(PrintStream out) {
        //        checkIO();
        //        setOut0(out); // native 方法，修改了out
        //   }
        System.setOut(new PrintStream("e:\f1.txt"));
        System.out.println("hello, Demo龙龙龙~");

    }
}

演示结果

package com;

import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;

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

        //PrintWriter printWriter = new PrintWriter(System.out);
        PrintWriter printWriter = new PrintWriter(new FileWriter("e:\f2.txt"));
        printWriter.print("hi, Demo龙你好~~~~");
        printWriter.close();//flush + 关闭流, 才会将数据写入到文件..

    }
}

演示结果