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brianwaybrianway
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[add] add io examples
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6 files changed

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‎java-io/src/main/java/com/brianway/learning/java/io/BufferedInputFile.java

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package com.brianway.learning.java.io;
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import java.io.BufferedReader;
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import java.io.FileReader;
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import java.io.IOException;
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/**
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* Created by brian on 16/11/28.
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*/
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public class BufferedInputFile {
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public static String read(String filename) throws IOException {
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BufferedReader in = new BufferedReader(
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new FileReader(filename));
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String s;
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StringBuilder sb = new StringBuilder();
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while ((s = in.readLine()) != null) {
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sb.append(s).append("\n");
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}
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in.close();
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return sb.toString();
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}
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public static void main(String[] args) throws IOException {
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String file = BufferedInputFile.class.getResource("/").getPath()
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+ "/infile.txt";
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System.out.print(read(file));
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}
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}

‎java-io/src/main/java/com/brianway/learning/java/io/Echo.java

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package com.brianway.learning.java.io;
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import java.io.BufferedReader;
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import java.io.IOException;
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import java.io.InputStreamReader;
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import java.io.PrintWriter;
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/**
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* Created by brian on 16/11/28.
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*
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* 从标准输入中读取,并将 System.out 转换成 PrintWriter
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*/
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public class Echo {
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public static void main(String[] args) throws IOException {
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BufferedReader stdin = new BufferedReader(
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new InputStreamReader(System.in));
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PrintWriter out = new PrintWriter(System.out, true);// 开启自动清空
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String s;
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while ((s = stdin.readLine()) != null && s.length() != 0) {
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//System.out.println(s);
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out.println(s);
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}
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}
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}

‎java-io/src/main/java/com/brianway/learning/java/io/FileOutput.java

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package com.brianway.learning.java.io;
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import java.io.BufferedReader;
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import java.io.BufferedWriter;
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import java.io.FileWriter;
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import java.io.IOException;
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import java.io.PrintWriter;
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import java.io.StringReader;
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/**
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* Created by brian on 16/11/28.
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*/
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public class FileOutput {
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/**
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* 基本的文件输出
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*/
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public static void basic(String infile, String outfile) throws IOException {
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BufferedReader in = new BufferedReader(
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new StringReader(
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BufferedInputFile.read(infile)));
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PrintWriter out = new PrintWriter(
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new BufferedWriter(new FileWriter(outfile)));
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int lineCount = 1;
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String s;
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while ((s = in.readLine()) != null) {
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out.println(lineCount++ + ": " + s);
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}
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out.close();
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System.out.println(BufferedInputFile.read(outfile));
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}
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/**
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* 文本文件输出的快捷方式
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*/
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public static void shortcut(String infile, String outfile)throws IOException{
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BufferedReader in = new BufferedReader(
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new StringReader(
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BufferedInputFile.read(infile)));
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PrintWriter out = new PrintWriter(outfile);
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int lineCount = 1;
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String s;
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while ((s = in.readLine()) != null) {
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out.println(lineCount++ + ": " + s);
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}
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out.close();
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System.out.println(BufferedInputFile.read(outfile));
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}
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public static void main(String[] args) throws IOException {
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String parent = BufferedInputFile.class.getResource("/").getPath();
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String infile = parent + "/infile.txt";
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String outfile = parent + "/BasicOut";
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basic(infile, outfile);
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outfile = parent+"ShortcutOut";
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shortcut(infile,outfile);
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}
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}

‎java-io/src/main/java/com/brianway/learning/java/io/MemoryInput.java

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package com.brianway.learning.java.io;
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import java.io.ByteArrayInputStream;
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import java.io.DataInputStream;
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import java.io.IOException;
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import java.io.StringReader;
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/**
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* Created by brian on 16/11/28.
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* 内存输入
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*/
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public class MemoryInput {
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/**
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* 从内存输入
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*/
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public static void useStringReader(String filename) {
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try {
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StringReader in = new StringReader(
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BufferedInputFile.read(filename));
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int c;
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while ((c = in.read()) != -1)
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System.out.print((char) c);
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} catch (IOException e) {
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e.printStackTrace();
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}
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}
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/**
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* 格式化的内存输入
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*/
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public static void readFormattedInput(String filename) {
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try {
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DataInputStream in = new DataInputStream(
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new ByteArrayInputStream(
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BufferedInputFile.read(filename)
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.getBytes()));
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while (in.available() != 0) {
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System.out.print((char) in.readByte());
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}
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} catch (IOException e) {
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e.printStackTrace();
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}
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}
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public static void main(String[] args)
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throws IOException {
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String filename = BufferedInputFile.class.getResource("/").getPath()
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+ "/infile.txt";
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useStringReader(filename);
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readFormattedInput(filename);
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}
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}

‎java-io/src/main/java/com/brianway/learning/java/io/TextFile.java

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package com.brianway.learning.java.io;
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import java.io.BufferedReader;
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import java.io.File;
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import java.io.FileReader;
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import java.io.IOException;
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import java.io.PrintWriter;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.TreeSet;
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/**
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* Static functions for reading and writing text files as
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* a single string, and treating a file as an ArrayList.
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*/
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public class TextFile extends ArrayList<String> {
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// Read a file as a single string:
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public static String read(String fileName) {
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StringBuilder sb = new StringBuilder();
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try {
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BufferedReader in = new BufferedReader(
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new FileReader(
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new File(fileName).getAbsoluteFile()));
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try {
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String s;
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while ((s = in.readLine()) != null) {
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sb.append(s);
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sb.append("\n");
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}
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} finally {
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try {
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in.close();
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} catch (IOException e) {
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e.printStackTrace();
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}
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}
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} catch (IOException e) {
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throw new RuntimeException(e);
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}
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return sb.toString();
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}
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// Write a single file in one method call:
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public static void write(String fileName, String text) {
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try {
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PrintWriter out = new PrintWriter(
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new File(fileName).getAbsoluteFile());
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try {
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out.print(text);
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} finally {
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out.close();
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}
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} catch (IOException e) {
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throw new RuntimeException(e);
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}
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}
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// Read a file, split by any regular expression:
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public TextFile(String fileName, String splitter) {
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super(Arrays.asList(read(fileName).split(splitter)));
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// Regular expression split() often leaves an empty
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// String at the first position:
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if (get(0).equals("")) remove(0);
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}
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// Normally read by lines:
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public TextFile(String fileName) {
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this(fileName, "\n");
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}
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public void write(String fileName) {
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try {
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PrintWriter out = new PrintWriter(
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new File(fileName).getAbsoluteFile());
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try {
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for (String item : this)
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out.println(item);
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} finally {
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out.close();
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}
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} catch (IOException e) {
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throw new RuntimeException(e);
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}
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}
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// Simple test:
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public static void main(String[] args) {
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String parent = BufferedInputFile.class.getResource("/").getPath();
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String inFileName = parent + "/infile.txt";
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String file = read(inFileName);
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write(parent + "/text.txt", file);
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TextFile text = new TextFile(parent + "/text.txt");
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text.write(parent + "test2.txt");
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// Break into unique sorted list of words:
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TreeSet<String> words = new TreeSet<String>(
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new TextFile(inFileName, "\\W+"));
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// Display the capitalized words:
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System.out.println(words.headSet("a"));
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}
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}
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‎java-io/src/main/resources/infile.txt

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-----------------------------------------
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public static String read(String filename) throws IOException {
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BufferedReader in = new BufferedReader(
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new FileReader(filename));
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String s;
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StringBuilder sb = new StringBuilder();
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while ((s = in.readLine()) != null) {
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sb.append(s).append("\n");
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}
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in.close();
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return sb.toString();
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}

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