Java 实现《编译原理》简单-语法分析功能-LL(1)文法 - 程序解析

àì夳堔傛蜴生んèń 2022-10-02 10:55 236阅读 0赞

### Java 实现《编译原理》简单-语法分析功能-LL(1)文法 - 程序解析 ###

编译原理学习，语法分析程序设计

#### （一）要求及功能 ####

已知 LL(1) 文法为：

G'[E]: E→TE'
           E'→+TE'|ε
           T→FT'
           T'→*FT'|ε
           F→(E)|i

**为了方便处理，用：M 代替 E’，N 代表 T’；并展开相同同一非终结符的产生式；不影响含义，可自行再优化**  
即有：

G[E]: E→TM
          M→+TM
          M→ε
          T→FN
          N→*FN
          N→ε
          F→(E)
          F→i

根据文法建立 LL(1) 分析表，并对输入串 i+i\*i 进行语法分析，判断其是否是合法的句子

#### （二）整体与执行结果 ####

**所需类：**

![在这里插入图片描述][20190618220347642.png]

**执行结果：**

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9pY29kZS5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9pY29kZS5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 1]

#### （三）程序源代码 ####

（1）Grammar.java 文件：

package com.java997.analyzer.grammar;
 
 import java.io.File;
 import java.io.FileWriter;
 import java.io.Serializable;
 import java.io.Writer;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Set;
 import java.util.TreeMap;
 import java.util.TreeSet;
 
 /** * * LL(1)文法 * 1.获取 First 集 * 2.获取 Follow 集 * 3.获取 SELECT 集 * * @author XiaoPengwei * @since 2019-06-18 */
 public class Grammar implements Serializable { 
 
 private static final long serialVersionUID = 1L;
 
 public Grammar() { 
 super();
 gsArray = new ArrayList<String>();
 nvSet = new TreeSet<Character>();
 ntSet = new TreeSet<Character>();
 firstMap = new HashMap<Character, TreeSet<Character>>();
 followMap = new HashMap<Character, TreeSet<Character>>();
 selectMap = new TreeMap<Character, HashMap<String, TreeSet<Character>>>();
 }
 
 private String[][] analyzeTable;
 
 /** * Select集合 */
 private TreeMap<Character, HashMap<String, TreeSet<Character>>> selectMap;
 
 /** * LL（1）文法产生集合 */
 private ArrayList<String> gsArray;
 
 /** * 表达式集合 */
 private HashMap<Character, ArrayList<String>> expressionMap;
 
 /** * 开始符 */
 private Character s;
 
 /** * Vn非终结符集合 */
 private TreeSet<Character> nvSet;
 
 /** * Vt终结符集合 */
 private TreeSet<Character> ntSet;
 
 /** * First集合 */
 private HashMap<Character, TreeSet<Character>> firstMap;
 
 /** * Follow集合 */
 private HashMap<Character, TreeSet<Character>> followMap;
 
 public String[][] getAnalyzeTable() { 
 return analyzeTable;
 }
 
 public void setAnalyzeTable(String[][] analyzeTable) { 
 this.analyzeTable = analyzeTable;
 }
 
 public TreeMap<Character, HashMap<String, TreeSet<Character>>> getSelectMap() { 
 return selectMap;
 }
 
 public void setSelectMap(TreeMap<Character, HashMap<String, TreeSet<Character>>> selectMap) { 
 this.selectMap = selectMap;
 }
 
 public HashMap<Character, TreeSet<Character>> getFirstMap() { 
 return firstMap;
 }
 
 public void setFirstMap(HashMap<Character, TreeSet<Character>> firstMap) { 
 this.firstMap = firstMap;
 }
 
 public HashMap<Character, TreeSet<Character>> getFollowMap() { 
 return followMap;
 }
 
 public void setFollowMap(HashMap<Character, TreeSet<Character>> followMap) { 
 this.followMap = followMap;
 }
 
 public HashMap<Character, ArrayList<String>> getExpressionMap() { 
 return expressionMap;
 }
 
 public void setExpressionMap(HashMap<Character, ArrayList<String>> expressionMap) { 
 this.expressionMap = expressionMap;
 }
 
 public ArrayList<String> getGsArray() { 
 return gsArray;
 }
 
 public void setGsArray(ArrayList<String> gsArray) { 
 this.gsArray = gsArray;
 }
 
 public Character getS() { 
 return s;
 }
 
 public void setS(Character s) { 
 this.s = s;
 }
 
 public TreeSet<Character> getNvSet() { 
 return nvSet;
 }
 
 public void setNvSet(TreeSet<Character> nvSet) { 
 this.nvSet = nvSet;
 }
 
 public TreeSet<Character> getNtSet() { 
 return ntSet;
 }
 
 public void setNtSet(TreeSet<Character> ntSet) { 
 this.ntSet = ntSet;
 }
 
 /** * 获取非终结符集与终结符集 */
 public void getNvNt() { 
 for (String gsItem : gsArray) { 
 String[] nvNtItem = gsItem.split("->");
 String charItemStr = nvNtItem[0];
 char charItem = charItemStr.charAt(0);
 // nv在左边
 nvSet.add(charItem);
 }
 for (String gsItem : gsArray) { 
 String[] nvNtItem = gsItem.split("->");
 // nt在右边
 String nvItemStr = nvNtItem[1];
 // 遍历每一个字
 for (int i = 0; i < nvItemStr.length(); i++) { 
 char charItem = nvItemStr.charAt(i);
 if (!nvSet.contains(charItem)) { 
 ntSet.add(charItem);
 }
 }
 }
 }
 
 /** * 初始化表达式集合 */
 public void initExpressionMaps() { 
 expressionMap = new HashMap<Character, ArrayList<String>>();
 for (String gsItem : gsArray) { 
 String[] nvNtItem = gsItem.split("->");
 String charItemStr = nvNtItem[0];
 String charItemRightStr = nvNtItem[1];
 char charItem = charItemStr.charAt(0);
 if (!expressionMap.containsKey(charItem)) { 
 ArrayList<String> expArr = new ArrayList<String>();
 expArr.add(charItemRightStr);
 expressionMap.put(charItem, expArr);
 } else { 
 ArrayList<String> expArr = expressionMap.get(charItem);
 expArr.add(charItemRightStr);
 expressionMap.put(charItem, expArr);
 }
 }
 }
 
 /** * 获取 First 集 */
 public void getFirst() { 
 // 遍历所有Nv,求出它们的First集合
 Iterator<Character> iterator = nvSet.iterator();
 while (iterator.hasNext()) { 
 Character charItem = iterator.next();
 ArrayList<String> arrayList = expressionMap.get(charItem);
 for (String itemStr : arrayList) { 
 boolean shouldBreak = false;
 // Y1Y2Y3...Yk
 for (int i = 0; i < itemStr.length(); i++) { 
 char itemitemChar = itemStr.charAt(i);
 TreeSet<Character> itemSet = firstMap.get(charItem);
 if (null == itemSet) { 
 itemSet = new TreeSet<Character>();
 }
 shouldBreak = calcFirst(itemSet, charItem, itemitemChar);
 if (shouldBreak) { 
 break;
 }
 }
 }
 }
 }
 
 /** * 计算 First 函数 * * @param itemSet * @param charItem * @param itemitemChar * @return boolean */
 private boolean calcFirst(TreeSet<Character> itemSet, Character charItem, char itemitemChar) { 
 
 // 将它的每一位和Nt判断下
 // 是终结符或空串,就停止，并将它加到FirstMap中
 if (itemitemChar == 'ε' || ntSet.contains(itemitemChar)) { 
 itemSet.add(itemitemChar);
 firstMap.put(charItem, itemSet);
 // break;
 return true;
 } else if (nvSet.contains(itemitemChar)) { // 这一位是一个非终结符
 ArrayList<String> arrayList = expressionMap.get(itemitemChar);
 for (int i = 0; i < arrayList.size(); i++) { 
 String string = arrayList.get(i);
 char tempChar = string.charAt(0);
 calcFirst(itemSet, charItem, tempChar);
 }
 }
 return true;
 }
 
 /** * 获取 Follow 集合 */
 public void getFollow() { 
 for (Character tempKey : nvSet) { 
 TreeSet<Character> tempSet = new TreeSet<Character>();
 followMap.put(tempKey, tempSet);
 }
 // 遍历所有Nv,求出它们的First集合
 Iterator<Character> iterator = nvSet.descendingIterator();
 
 while (iterator.hasNext()) { 
 Character charItem = iterator.next();
 System.out.println("charItem:" + charItem);
 Set<Character> keySet = expressionMap.keySet();
 for (Character keyCharItem : keySet) { 
 ArrayList<String> charItemArray = expressionMap.get(keyCharItem);
 for (String itemCharStr : charItemArray) { 
 System.out.println(keyCharItem + "->" + itemCharStr);
 TreeSet<Character> itemSet = followMap.get(charItem);
 calcFollow(charItem, charItem, keyCharItem, itemCharStr, itemSet);
 }
 }
 }
 }
 
 /** * 计算 Follow 集 * * @param putCharItem 正在查询item * @param charItem 待找item * @param keyCharItem 节点名 * @param itemCharStr 符号集 * @param itemSet 结果集合 */
 private void calcFollow(Character putCharItem, Character charItem, Character keyCharItem, String itemCharStr,
 TreeSet<Character> itemSet) { 
 
 // （1）A是S（开始符)，加入#
 if (charItem.equals(s)) { 
 itemSet.add('#');
 System.out.println("---------------find S:" + charItem + " ={#}+Follow(E)");
 followMap.put(putCharItem, itemSet);
 
 }
 // (2)Ab,=First(b)-ε,直接添加终结符
 if (TextUtil.containsAb(ntSet, itemCharStr, charItem)) { 
 Character alastChar = TextUtil.getAlastChar(itemCharStr, charItem);
 System.out.println("---------------find Ab:" + itemCharStr + " " + charItem + " =" + alastChar);
 itemSet.add(alastChar);
 followMap.put(putCharItem, itemSet);
 // return;
 }
 // (2).2AB,=First(B)-ε,=First(B)-ε，添加first集合
 if (TextUtil.containsAB(nvSet, itemCharStr, charItem)) { 
 Character alastChar = TextUtil.getAlastChar(itemCharStr, charItem);
 System.out.println(
 "---------------find AB:" + itemCharStr + " " + charItem + " =First(" + alastChar + ")");
 TreeSet<Character> treeSet = firstMap.get(alastChar);
 itemSet.addAll(treeSet);
 if (treeSet.contains('ε')) { 
 itemSet.add('#');
 }
 itemSet.remove('ε');
 followMap.put(putCharItem, itemSet);
 
 if (TextUtil.containsbAbIsNull(nvSet, itemCharStr, charItem, expressionMap)) { 
 char tempChar = TextUtil.getAlastChar(itemCharStr, charItem);
 System.out.println("tempChar:" + tempChar + " key" + keyCharItem);
 if (!keyCharItem.equals(charItem)) { 
 System.out.println("---------------find tempChar bA: " + "tempChar:" + tempChar + keyCharItem
 + " " + itemCharStr + " " + charItem + " =Follow(" + keyCharItem + ")");
 Set<Character> keySet = expressionMap.keySet();
 for (Character keyCharItems : keySet) { 
 ArrayList<String> charItemArray = expressionMap.get(keyCharItems);
 for (String itemCharStrs : charItemArray) { 
 calcFollow(putCharItem, keyCharItem, keyCharItems, itemCharStrs, itemSet);
 }
 }
 }
 }
 }
 // (3)B->aA,=Follow(B),添加followB
 if (TextUtil.containsbA(nvSet, itemCharStr, charItem, expressionMap)) { 
 if (!keyCharItem.equals(charItem)) { 
 System.out.println("---------------find bA: " + keyCharItem + " " + itemCharStr + " " + charItem
 + " =Follow(" + keyCharItem + ")");
 Set<Character> keySet = expressionMap.keySet();
 for (Character keyCharItems : keySet) { 
 ArrayList<String> charItemArray = expressionMap.get(keyCharItems);
 for (String itemCharStrs : charItemArray) { 
 calcFollow(putCharItem, keyCharItem, keyCharItems, itemCharStrs, itemSet);
 }
 }
 }
 }
 }
 
 /** * 获取 Select 集合 */
 public void getSelect() { 
 // 遍历每一个表达式
 // HashMap<Character, HashMap<String, TreeSet<Character>>>
 Set<Character> keySet = expressionMap.keySet();
 for (Character selectKey : keySet) { 
 ArrayList<String> arrayList = expressionMap.get(selectKey);
 // 每一个表达式
 HashMap<String, TreeSet<Character>> selectItemMap = new HashMap<String, TreeSet<Character>>();
 for (String selectExp : arrayList) { 
 /** * 存放select结果的集合 */
 TreeSet<Character> selectSet = new TreeSet<Character>();
 // set里存放的数据分3种情况,由selectExp决定
 // 1.A->ε,=follow(A)
 if (TextUtil.isEmptyStart(selectExp)) { 
 selectSet = followMap.get(selectKey);
 selectSet.remove('ε');
 selectItemMap.put(selectExp, selectSet);
 }
 // 2.Nt开始,=Nt
 // 终结符开始
 if (TextUtil.isNtStart(ntSet, selectExp)) { 
 selectSet.add(selectExp.charAt(0));
 selectSet.remove('ε');
 selectItemMap.put(selectExp, selectSet);
 }
 // 3.Nv开始，=first(Nv)
 if (TextUtil.isNvStart(nvSet, selectExp)) { 
 selectSet = firstMap.get(selectKey);
 selectSet.remove('ε');
 selectItemMap.put(selectExp, selectSet);
 }
 selectMap.put(selectKey, selectItemMap);
 }
 }
 }
 
 /** * 生成预测分析表 */
 public void genAnalyzeTable() throws Exception { 
 Object[] ntArray = ntSet.toArray();
 Object[] nvArray = nvSet.toArray();
 // 预测分析表初始化
 analyzeTable = new String[nvArray.length + 1][ntArray.length + 1];
 
 System.out.println("====================\n预测分析表\n====================");
 
 File outputFile = new File("D:\\template\\analyzer\\src\\main\\java\\com\\java997\\analyzer\\grammar\\analyzeTable.txt");
 try (Writer writer = new FileWriter(outputFile)) { 
 writer.write("====================\n预测分析表\n====================\n");
 // 输出一个占位符
 System.out.print("表" + "\t");
 writer.write("表" + "\t");
 analyzeTable[0][0] = "Nv/Nt";
 
 // 初始化首行
 for (int i = 0; i < ntArray.length; i++) { 
 if (ntArray[i].equals('ε')) { 
 ntArray[i] = '#';
 }
 writer.write(ntArray[i] + "\t\t");
 System.out.print(ntArray[i] + "\t\t");
 
 analyzeTable[0][i + 1] = ntArray[i] + "";
 }
 
 System.out.println("");
 writer.write("\n");
 for (int i = 0; i < nvArray.length; i++) { 
 // 首列初始化
 writer.write(nvArray[i] + "\t");
 System.out.print(nvArray[i] + "\t");
 
 analyzeTable[i + 1][0] = nvArray[i] + "";
 for (int j = 0; j < ntArray.length; j++) { 
 String findUseExp = TextUtil.findUseExp(selectMap, Character.valueOf((Character) nvArray[i]),
 Character.valueOf((Character) ntArray[j]));
 if (null == findUseExp) { 
 writer.write("空\t\t");
 System.out.print("空\t\t");
 
 analyzeTable[i + 1][j + 1] = "";
 } else { 
 writer.write(nvArray[i] + "->" + findUseExp + "\t");
 System.out.print(nvArray[i] + "->" + findUseExp + "\t");
 
 analyzeTable[i + 1][j + 1] = nvArray[i] + "->" + findUseExp;
 }
 }
 writer.write("\n");
 System.out.println();
 }
 } catch (Exception e) { 
 e.printStackTrace();
 }
 }
 }

（2）Analyzer.java

package com.java997.analyzer.grammar;
 
 import java.util.ArrayList;
 import java.util.Stack;
 
 /** * * 主程序 句子分析器 * * @author XiaoPengwei * @since 2019-06-18 */
 public class Analyzer { 
 
 public Analyzer() { 
 super();
 analyzeStatck = new Stack<Character>();
 // 结束符进栈
 analyzeStatck.push('#');
 }
 
 private ArrayList<AnalyzeProduce> analyzeProduces;
 
 /** * LL（1）文法 */
 private Grammar ll1Grammar;
 
 public Grammar getLl1Grammar() { 
 return ll1Grammar;
 }
 
 public void setLl1Grammar(Grammar ll1Grammar) { 
 this.ll1Grammar = ll1Grammar;
 }
 
 /** * 开始符 */
 private Character startChar;
 
 /** * 分析栈 */
 private Stack<Character> analyzeStatck;
 /** * 剩余输入串 */
 private String str;
 /** * 推导所用产生或匹配 */
 private String useExp;
 
 public ArrayList<AnalyzeProduce> getAnalyzeProduces() { 
 return analyzeProduces;
 }
 
 public void setAnalyzeProduces(ArrayList<AnalyzeProduce> analyzeProduces) { 
 this.analyzeProduces = analyzeProduces;
 }
 
 public Character getStartChar() { 
 return startChar;
 }
 
 public void setStartChar(Character startChar) { 
 this.startChar = startChar;
 }
 
 public Stack<Character> getAnalyzeStatck() { 
 return analyzeStatck;
 }
 
 public void setAnalyzeStatck(Stack<Character> analyzeStatck) { 
 this.analyzeStatck = analyzeStatck;
 }
 
 public String getStr() { 
 return str;
 }
 
 public void setStr(String str) { 
 this.str = str;
 }
 
 public String getUseExp() { 
 return useExp;
 }
 
 public void setUseExp(String useExp) { 
 this.useExp = useExp;
 }
 
 /** * 分析 */
 public void analyze() { 
 analyzeProduces = new ArrayList<AnalyzeProduce>();
 
 // 开始符进栈
 analyzeStatck.push(startChar);
 
 System.out.println("====================\nLL(1)文法分析过程\n====================");
 System.out.println("开始符:" + startChar);
 System.out.println("序号\t\t符号栈\t\t\t输入串\t\t\t所用产生式");
 int index = 0;
 // 开始分析
 // while (analyzeStatck.peek() != '#' && str.charAt(0) != '#') { 
 while (!analyzeStatck.empty()) { 
 index++;
 if (analyzeStatck.peek() != str.charAt(0)) { 
 
 // 到分析表中找到这个产生式
 String nowUseExpStr = TextUtil.findUseExp(ll1Grammar.getSelectMap(), analyzeStatck.peek(), str.charAt(0));
 
 //打印表格注意, 制表符的个数
 if (analyzeStatck.size()==1){ 
 System.out.println(index + "\t\t" + analyzeStatck.toString() + "\t\t\t\t" + str + "\t\t\t"
 + analyzeStatck.peek() + "->" + nowUseExpStr);
 }else if (analyzeStatck.size()==2){ 
 System.out.println(index + "\t\t" + analyzeStatck.toString() + "\t\t\t" + str + "\t\t\t"
 + analyzeStatck.peek() + "->" + nowUseExpStr);
 }else if (analyzeStatck.size()==3){ 
 System.out.println(index + "\t\t" + analyzeStatck.toString() + "\t\t" + str + "\t\t\t"
 + analyzeStatck.peek() + "->" + nowUseExpStr);
 }else { 
 System.out.println(index + "\t\t" + analyzeStatck.toString() + "\t" + str + "\t\t\t"
 + analyzeStatck.peek() + "->" + nowUseExpStr);
 }
 
 AnalyzeProduce produce = new AnalyzeProduce();
 produce.setIndex(index);
 produce.setAnalyzeStackStr(analyzeStatck.toString());
 produce.setStr(str);
 if (null == nowUseExpStr) { 
 produce.setUseExpStr("无法匹配!");
 } else { 
 produce.setUseExpStr(analyzeStatck.peek() + "->" + nowUseExpStr);
 }
 analyzeProduces.add(produce);
 // 将之前的分析栈中的栈顶出栈
 analyzeStatck.pop();
 // 将要用到的表达式入栈,反序入栈
 if (null != nowUseExpStr && nowUseExpStr.charAt(0) != 'ε') { 
 for (int j = nowUseExpStr.length() - 1; j >= 0; j--) { 
 char currentChar = nowUseExpStr.charAt(j);
 analyzeStatck.push(currentChar);
 }
 }
 continue;
 }
 // 如果可以匹配,分析栈出栈，串去掉一位
 if (analyzeStatck.peek() == str.charAt(0)) { 
 
 if (analyzeStatck.size()==1){ 
 System.out.println(index + "\t\t" + analyzeStatck.toString() + "\t\t\t\t" + str + "\t\t\t" + "“"
 + str.charAt(0) + "”匹配");
 }else if (analyzeStatck.size()==2){ 
 System.out.println(index + "\t\t" + analyzeStatck.toString() + "\t\t\t" + str + "\t\t\t" + "“"
 + str.charAt(0) + "”匹配");
 }else if (analyzeStatck.size()==3){ 
 System.out.println(index + "\t\t" + analyzeStatck.toString() + "\t\t" + str + "\t\t\t" + "“"
 + str.charAt(0) + "”匹配");
 }else { 
 System.out.println(index + "\t\t" + analyzeStatck.toString() + "\t" + str + "\t\t\t" + "“"
 + str.charAt(0) + "”匹配");
 }
 
 AnalyzeProduce produce = new AnalyzeProduce();
 produce.setIndex(index);
 produce.setAnalyzeStackStr(analyzeStatck.toString());
 produce.setStr(str);
 produce.setUseExpStr("“" + str.charAt(0) + "”匹配");
 analyzeProduces.add(produce);
 analyzeStatck.pop();
 str = str.substring(1);
 continue;
 }
 }
 }
 }

（3）AnalyzeProduce.java

package com.java997.analyzer.grammar;
 
 import java.io.Serializable;
 
 /** * * 分析过程 Bean * * @author XiaoPengwei * @since 2019-06-18 */
 public class AnalyzeProduce implements Serializable { 
 private static final long serialVersionUID = 10L;
 private Integer index;
 private String analyzeStackStr;
 private String str;
 private String useExpStr;
 
 public Integer getIndex() { 
 return index;
 }
 
 public void setIndex(Integer index) { 
 this.index = index;
 }
 
 public String getAnalyzeStackStr() { 
 return analyzeStackStr;
 }
 
 public void setAnalyzeStackStr(String analyzeStackStr) { 
 this.analyzeStackStr = analyzeStackStr;
 }
 
 public String getStr() { 
 return str;
 }
 
 public void setStr(String str) { 
 this.str = str;
 }
 
 public String getUseExpStr() { 
 return useExpStr;
 }
 
 public void setUseExpStr(String useExpStr) { 
 this.useExpStr = useExpStr;
 }
 
 }

（4）Main.java

package com.java997.analyzer.grammar;
 
 import java.util.ArrayList;
 import java.util.TreeSet;
 
 /** * * 主程序 * * @author XiaoPengwei * @since 2019-06-18 */
 public class Main { 
 
 public static void main(String[] args) throws Exception { 
 
 // 第一步：获取 LL(1)文法
 ArrayList<String> gsArray = new ArrayList<String>();
 Grammar grammar = new Grammar();
 
 //初始化 LL(1), 设定该文法的产生式
 initGs(gsArray);
 
 grammar.setGsArray(gsArray);
 grammar.getNvNt();
 grammar.initExpressionMaps();
 grammar.getFirst();
 
 // 设置开始符
 grammar.setS('E');
 grammar.getFollow();
 grammar.getSelect();
 
 //打印预测分析表, 并保存文件
 grammar.genAnalyzeTable();
 
 // 创建一个分析器
 Analyzer analyzer = new Analyzer();
 
 // 设定开始符号
 analyzer.setStartChar('E');
 analyzer.setLl1Grammar(grammar);
 
 // 待分析的字符串
 analyzer.setStr("i+i*i#");
 
 // 执行分析, 打印分析步骤, 保存文件
 analyzer.analyze();
 
 }
 
 /** * 获取非终结符集与终结符集 * * @param gsArray * @param nvSet * @param ntSet */
 private static void getNvNt(ArrayList<String> gsArray, TreeSet<Character> nvSet, TreeSet<Character> ntSet) { 
 for (String gsItem : gsArray) { 
 String[] nvNtItem = gsItem.split("->");
 String charItemStr = nvNtItem[0];
 char charItem = charItemStr.charAt(0);
 // nv在左边
 nvSet.add(charItem);
 }
 for (String gsItem : gsArray) { 
 String[] nvNtItem = gsItem.split("->");
 // nt在右边
 String nvItemStr = nvNtItem[1];
 // 遍历每一个字
 for (int i = 0; i < nvItemStr.length(); i++) { 
 char charItem = nvItemStr.charAt(i);
 if (!nvSet.contains(charItem)) { 
 ntSet.add(charItem);
 }
 }
 }
 
 }
 
 /** * 初始化 LL(1)文法, 设定产生式 * * @param gsArray */
 private static void initGs(ArrayList<String> gsArray) { 
 //E' = M
 //T' = N
 gsArray.add("E->TM");
 gsArray.add("M->+TF");
 gsArray.add("M->ε");
 gsArray.add("T->FN");
 gsArray.add("N->*FN");
 gsArray.add("N->ε");
 gsArray.add("F->(E)");
 gsArray.add("F->i");
 }
 }

（5）TextUtil.java

package com.java997.analyzer.grammar;
 
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Set;
 import java.util.TreeMap;
 import java.util.TreeSet;
 
 /** * * 字符工具类 * * @author XiaoPengwei * @since 2019-06-18 */
 public class TextUtil { 
 
 /** * (3)B->aA,=Follow(B) * * @param nvSet * @param itemCharStr * @param a * @param expressionMap */
 public static boolean containsbA(TreeSet<Character> nvSet, String itemCharStr, Character a,
 HashMap<Character, ArrayList<String>> expressionMap) { 
 String aStr = a.toString();
 String lastStr = itemCharStr.substring(itemCharStr.length() - 1);
 return lastStr.equals(aStr);
 }
 
 /** * 形如 aBb,b=空 * * @param nvSet * @param itemCharStr * @param a * @param expressionMap */
 public static boolean containsbAbIsNull(TreeSet<Character> nvSet, String itemCharStr, Character a,
 HashMap<Character, ArrayList<String>> expressionMap) { 
 String aStr = a.toString();
 if (containsAB(nvSet, itemCharStr, a)) { 
 Character alastChar = getAlastChar(itemCharStr, a);
 System.out.println("----------------+++++++++++++++++++--" + expressionMap.toString());
 ArrayList<String> arrayList = expressionMap.get(alastChar);
 if (arrayList.contains("ε")) { 
 System.out.println(alastChar + " contains('ε')" + aStr);
 return true;
 }
 }
 return false;
 
 }
 
 /** *是否包含这种的字符串 * (2)Ab,=First(b)-ε,直接添加终结符 * * @param ntSet * @param itemCharStr * @param a * @return boolean */
 public static boolean containsAb(TreeSet<Character> ntSet, String itemCharStr, Character a) { 
 String aStr = a.toString();
 if (itemCharStr.contains(aStr)){ 
 int aIndex = itemCharStr.indexOf(aStr);
 String findStr;
 try { 
 findStr = itemCharStr.substring(aIndex + 1, aIndex + 2);
 } catch (Exception e) { 
 return false;
 }
 return ntSet.contains(findStr.charAt(0));
 } else { 
 return false;
 }
 }
 
 /** * 是否包含这种的字符串 * (2).2Ab,=First(b)-ε * @param nvSet * @param itemCharStr * @param a * @return boolean */
 public static boolean containsAB(TreeSet<Character> nvSet, String itemCharStr, Character a) { 
 String aStr = a.toString();
 if (itemCharStr.contains(aStr)) { 
 int aIndex = itemCharStr.indexOf(aStr);
 String findStr;
 try { 
 findStr = itemCharStr.substring(aIndex + 1, aIndex + 2);
 } catch (Exception e) { 
 return false;
 }
 return nvSet.contains(findStr.charAt(0));
 } else { 
 return false;
 }
 }
 
 /** * 获取 A 后的字符 * * @param itemCharStr * @param a */
 public static Character getAlastChar(String itemCharStr, Character a) { 
 String aStr = a.toString();
 if (itemCharStr.contains(aStr)) { 
 int aIndex = itemCharStr.indexOf(aStr);
 String findStr = "";
 try { 
 findStr = itemCharStr.substring(aIndex + 1, aIndex + 2);
 } catch (Exception e) { 
 return null;
 }
 return findStr.charAt(0);
 }
 return null;
 }
 
 /** * 是否为 ε 开始的 * * @param selectExp */
 public static boolean isEmptyStart(String selectExp) { 
 char charAt = selectExp.charAt(0);
 return charAt == 'ε';
 }
 
 /** * 是否是终结符开始的 * * @param ntSet * @param selectExp */
 public static boolean isNtStart(TreeSet<Character> ntSet, String selectExp) { 
 char charAt = selectExp.charAt(0);
 return ntSet.contains(charAt);
 }
 
 /** * 是否是非终结符开始的 * * @param nvSet * @param selectExp * @return */
 public static boolean isNvStart(TreeSet<Character> nvSet, String selectExp) { 
 char charAt = selectExp.charAt(0);
 return nvSet.contains(charAt);
 }
 
 /** * 查找产生式 * * @param selectMap * @param peek 当前 Nv * @param charAt 当前字符 * @return */
 public static String findUseExp(TreeMap<Character, HashMap<String, TreeSet<Character>>> selectMap, Character peek,
 char charAt) { 
 try { 
 HashMap<String, TreeSet<Character>> hashMap = selectMap.get(peek);
 Set<String> keySet = hashMap.keySet();
 for (String useExp : keySet) { 
 TreeSet<Character> treeSet = hashMap.get(useExp);
 if (treeSet.contains(charAt)) { 
 return useExp;
 }
 }
 } catch (Exception e) { 
 return null;
 }
 return null;
 }
 }

执行 Main.java

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[20190618220347642.png]: /images/20220112/2520d954902e4226a6a4e090db01d770.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9pY29kZS5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70]: /images/20220112/a34dbd7f03ea4666befa0883884e8ff4.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9pY29kZS5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 1]: /images/20220112/cc74baa9100d4321a4a7627ffe122002.png