2020101501

Secondary Namenode莫名其妙无法启动的原因找到。是端口被Eclipse占用的缘故。
同时，要求的文本编辑也编写完成。在设计的时候在编译原理的启发下做了个带有词法分析器+状态机(但是状态机对语法的分析有一些问题)的版本，模拟了一个简单的指令系统并且使得输入支持代表换行、代表制表符、\代表的等字符的转义。
源代码如下：
  1 package konoha.pkg.p01;
  2 
  3 import java.io.BufferedReader;
  4 import java.io.BufferedWriter;
  5 import java.io.IOException;
  6 import java.io.InputStream;
  7 import java.io.InputStreamReader;
  8 import java.io.OutputStreamWriter;
  9 import java.net.MalformedURLException;
 10 import java.net.URL;
 11 import java.util.Scanner;
 12 
 13 import org.apache.hadoop.conf.Configuration;
 14 import org.apache.hadoop.fs.FSDataOutputStream;
 15 import org.apache.hadoop.fs.FileSystem;
 16 import org.apache.hadoop.fs.FsUrlStreamHandlerFactory;
 17 import org.apache.hadoop.fs.Path;
 18 
 19 public class Type0TextEditor {
 20     private static Configuration conf;
 21     static {
 22         URL.setURLStreamHandlerFactory(new FsUrlStreamHandlerFactory());
 23     }
 24 
 25     public static void Config() {
 26         conf = new Configuration();
 27         conf.set("fs.defaultFS", "hdfs://localhost:9000");
 28         conf.set("fs.hdfs.impl", "org.apache.hadoop.hdfs.DistributedFileSystem");
 29     }
 30 
 31     public static boolean hasFile(String path) {
 32         try (FileSystem fs = FileSystem.get(conf)) {
 33             return fs.exists(new Path(path));
 34         } catch (IOException e) {
 35             e.printStackTrace();
 36             return false;
 37         }
 38     }
 39 
 40     public static String readFile(String filePath) {
 41         InputStream in = null;
 42         String rtn = "";
 43         try {
 44             in = new URL(filePath).openStream();
 45             BufferedReader br = new BufferedReader(new InputStreamReader(in));
 46             String tmp = null;
 47             boolean flag = true;
 48             while ((tmp = br.readLine()) != null) {
 49                 if (flag) {
 50                     flag = false;
 51                 } else {
 52                     rtn = rtn + "
";
 53                 }
 54                 rtn = rtn + tmp;
 55             }
 56         } catch (MalformedURLException e) {
 57             e.printStackTrace();
 58         } catch (IOException e) {
 59             e.printStackTrace();
 60         }
 61         return rtn;
 62     }
 63 
 64     public static void writeFile(String content, String filePath) {
 65         BufferedWriter bw = null;
 66         try {
 67             FileSystem fs = FileSystem.get(conf);
 68             FSDataOutputStream fout = fs.create(new Path(filePath));
 69             bw = new BufferedWriter(new OutputStreamWriter(fout, "UTF-8"));
 70             bw.write(content);
 71             bw.newLine();
 72             bw.flush();
 73         } catch (IOException e) {
 74             // TODO Auto-generated catch block
 75             e.printStackTrace();
 76         } finally {
 77             if (bw != null) {
 78                 try {
 79                     bw.close();
 80                 } catch (IOException e) {
 81                     // TODO Auto-generated catch block
 82                     e.printStackTrace();
 83                 }
 84             }
 85         }
 86     }
 87 
 88     public static void mkFile(String filePath) {
 89     }
 90 
 91     public static void main(String[] args) {
 92         Type0TextEditor.Config();
 93         String filePath = "hdfs://localhost:9000/user/test/0.txt";
 94         String content = "";
 95         Scanner ipt = new Scanner(System.in);
 96         String input = "";
 97         String inputPart = "";
 98         int operation = -1;
 99         boolean noExit = true;
100         boolean commandFlag = false;
101         boolean strFlag = false;
102         while (noExit) {
103             if (ipt.hasNextLine()) {
104                 input = ipt.nextLine() + " ";
105             }
106             inputPart = "";
107             operation = -1;
108             commandFlag = false;
109             strFlag = false;
110             filePath = "";
111             content = "";
112             // 输入解析
113             for (int i = 0; i < input.length(); i++) {
114                 if (input.charAt(i) == '
') {
115                     continue;
116                 }
117                 if (!strFlag) {
118                     if (input.charAt(i) != '"') {
119                         if (input.charAt(i) != ' ') {
120                             inputPart = inputPart + input.charAt(i);
121                         } else if (input.charAt(i) == ' ') {
122                             if (!inputPart.equals("")) {
123                                 if (inputPart.equals("open") && operation == -1) {
124                                     operation = 0;
125                                 } else if (inputPart.equals("new") && operation == -1) {
126                                     operation = 1;
127                                 } else if (inputPart.equals("insert") && operation == -1) {
128                                     operation = 2;
129                                 } else if (inputPart.equals("-start") && operation == 2) {
130                                     operation = 3;
131                                 } else if (inputPart.equals("-end") && operation == 2) {
132                                     operation = 4;
133                                 } else if (inputPart.equals("exit") && operation == -1) {
134                                     operation = 5;
135                                 } else {
136                                     System.out.println("Syntax error![CODE:1]");
137                                     operation = -1;
138                                     break;
139                                 }
140                                 inputPart = "";
141                             }
142                         }
143                     } else {// 遇到'"'
144                         if (inputPart.equals("")) {
145                             strFlag = true;
146                         } else {
147                             System.out.println("Syntax error![CODE:2]");
148                             operation = -1;
149                             break;
150                         }
151                     }
152                 } else {// 字符串
153                     if (commandFlag) {
154                         if (input.charAt(i) == '\') {
155                             inputPart = inputPart + "\";
156                         } else if (input.charAt(i) == '"') {
157                             inputPart = inputPart + """;
158                         } else if (input.charAt(i) == 'n') {
159                             inputPart = inputPart + "
";
160                         } else if (input.charAt(i) == 't') {
161                             inputPart = inputPart + "	";
162                         } else {
163                             inputPart = inputPart + "\" + input.charAt(i);
164                         }
165                         commandFlag = false;
166                     } else {
167                         if (input.charAt(i) == '\') {
168                             commandFlag = true;
169                         } else if (input.charAt(i) == '"') {
170                             if (operation == 0 || operation == 1) {
171                                 if (filePath.equals("")) {
172                                     filePath = inputPart;
173                                     inputPart = "";
174                                 } else {
175                                     System.out.println("Syntax error![CODE:3]");
176                                     operation = -1;
177                                     break;
178                                 }
179                             } else if (operation == 2 || operation == 3 || operation == 4) {
180                                 if (filePath.equals("")) {
181                                     filePath = inputPart;
182                                     inputPart = "";
183                                 } else if (content.equals("")) {
184                                     content = inputPart;
185                                     inputPart = "";
186                                 } else {
187                                     System.out.println("Syntax error![CODE:4]");
188                                     operation = -1;
189                                     break;
190                                 }
191                             } else {
192                                 System.out.println("Syntax error![CODE:5]");
193                                 operation = -1;
194                                 break;
195                             }
196                             inputPart = "";
197                             strFlag = false;
198                         } else {
199                             inputPart = inputPart + input.charAt(i);
200                         }
201                     }
202                 }
203             }
204             // 解析完成
205             System.out.println("[]" + filePath + "||" + content + "[]");
206             if (operation == 0 && !filePath.equals("")) {
207                 if (hasFile(filePath)) {
208                     content = readFile(filePath);
209                     System.out.println("[OPEN]File "" + filePath + "" is Below");
210                     System.out.println(content);
211                 } else {
212                     System.out.println("[OPEN]No such file on " + filePath);
213                 }
214             } else if (operation == 1 && !filePath.equals("")) {
215                 writeFile("", filePath);
216                 System.out.println("[NEW]Created File on:" + filePath);
217             } else if ((operation == 2 || operation == 4) && !filePath.equals("") && !content.equals("")) {
218                 if (hasFile(filePath)) {
219                     writeFile(readFile(filePath) + content, filePath);
220                     System.out.println("[INSERT]Inserted content to end of " + filePath);
221                 } else {
222                     System.out.println("[INSERT]No such file on " + filePath);
223                 }
224             } else if (operation == 3 && !filePath.equals("") && !content.equals("")) {
225                 if (hasFile(filePath)) {
226                     writeFile(content + readFile(filePath), filePath);
227                     System.out.println("[INSERT]Inserted content to start of " + filePath);
228                 } else {
229                     System.out.println("[INSERT]No such file on " + filePath);
230                 }
231             } else if (operation == 5) {
232                 System.out.println("[EXIT]Exited Program");
233                 break;
234             } else {
235                 if (operation == 0) {
236                     System.out.println("[OPEN]Usage:
open <FilePath>");
237                 } else if (operation == 1) {
238                     System.out.println("[NEW]Usage:
new <FilePath>");
239                 } else if (operation == 2 || operation == 3 || operation == 4) {
240                     System.out.println("[INSERT]Usage:
insert [-start|-end] <FilePath> <ContentText>");
241                 } else {
242                 }
243             }
244         }
245 
246         ipt.close();
247     }
248 }
Type0TextEditor