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111 lines
2.8 KiB
111 lines
2.8 KiB
1.什么是IO流
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字符 = 字节 + 编码
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字节 = 字符 + 解码
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使用代码读取一个文本文件的数据时，只需要使用输入流即可
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2.字节流-输入输出
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package step2;
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import java.io.File;
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import java.io.FileInputStream;
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import java.io.FileNotFoundException;
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import java.io.FileOutputStream;
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import java.io.FileReader;
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import java.io.FileWriter;
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import java.io.IOException;
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public class Task {
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public void task() throws IOException{
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/********* Begin *********/
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File file = new File("src/step2/input/task.txt");
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FileInputStream fs = new FileInputStream(file);
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byte[] b = new byte[8];
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fs.read(b);
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String str = new String(b,"UTF-8");
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System.out.println(str);
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File dir = new File("src/step2/output");
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if(!dir.exists()){
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dir.mkdir();
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}
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FileOutputStream out = new FileOutputStream("src/step2/output/output.txt");
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String str1 = "learning practice";
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byte[] c = str1.getBytes();
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out.write(c);
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out.flush();
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fs.close();
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out.close();
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/********* End *********/
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}
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}
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3.字符流 - 输入输出
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package step3;
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import java.io.FileNotFoundException;
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import java.io.FileReader;
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import java.io.FileWriter;
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import java.io.IOException;
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public class Task {
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public void task() throws IOException{
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/********* Begin *********/
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String file1 = "src/step3/input/input.txt";
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FileReader fr = new FileReader(file1);
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char[] ch = new char[8];
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fr.read(ch);
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String file2 = "src/step3/output/output.txt";
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FileWriter fw = new FileWriter(file2);
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fw.write(ch);
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fr.close();
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fw.flush();
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fw.close();
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/********* End *********/
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}
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}
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4.复制文件
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package step4;
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import java.io.FileInputStream;
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import java.io.FileNotFoundException;
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import java.io.FileOutputStream;
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import java.io.FileReader;
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import java.io.FileWriter;
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import java.io.IOException;
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public class Task {
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public void task() throws IOException{
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/********* Begin *********/
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String file1 = "src/step4/input/input.txt";
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FileInputStream fr = new FileInputStream(file1);
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byte[] b = new byte[1024];
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int len = 0;
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String file2 = "src/step4/output/output.txt";
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FileOutputStream fw = new FileOutputStream(file2);
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while((len = fr.read(b))!=-1){
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fw.write(b,0,len);
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}
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fr.close();
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fw.close();
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String file3 = "src/step4/input/input.jpg";
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String file4 = "src/step4/output/output.jpg";
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FileInputStream fs = new FileInputStream(file3);
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FileOutputStream fos = new FileOutputStream(file4);
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len = 0;
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byte[] bys = new byte[1024];
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while( (len = fs.read(bys)) != -1){
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fos.write(bys, 0, len);
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}
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fs.close();
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fos.close();
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/********* End *********/
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}
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} |