读取JDK API文档，并根据单词出现频率排序

约定不等于承诺〃 2022-04-02 13:38 207阅读 0赞

### 1，拿到 API 文档 ###

选中特定的类，然后 copy 其中的内容，

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc1MDIxMg_size_16_color_FFFFFF_t_70]  
放入 TXT 文件中 ，  
![在这里插入图片描述][20181226204615648.png]

### 2，读取TXT内容，并排序 ###

package com.lgx.test;
    
    import java.io.BufferedReader;
    import java.io.File;
    import java.io.FileNotFoundException;
    import java.io.FileReader;
    import java.io.IOException;
    import java.util.ArrayList;
    import java.util.Collections;
    import java.util.Comparator;
    import java.util.List;
    import java.util.Map;
    import java.util.Map.Entry;
    import java.util.Set;
    import java.util.TreeMap;
    
    public class ReadVectorAPI { 
    
    	public static String filename = "src/Vector.txt";
    	public static StringBuffer sb = null;
    
    	public static void main(String[] args) { 
    		try { 
    			//根据单词字母排序
    			countWordOrderByWord();
    			//根据单词频率排序
    			countWordOrderByCount();
    		} catch (FileNotFoundException e) { 
    			e.printStackTrace();
    		}
    	}
    
    	// 计算单词的出现次数,依据单词排序
    	public static void countWordOrderByWord() throws FileNotFoundException { 
    		BufferedReader br = null;
    		try { 
    			br = new BufferedReader(new FileReader(new File(filename)));
    			String inputLine = null;
    			TreeMap<String, Integer> map = new TreeMap<String, Integer>();
    			while ((inputLine = br.readLine()) != null) { 
    				String[] words = inputLine.split("[ \n\t\r.,;:!?(){}]");
    				for (int i = 0; i < words.length; i++) { 
    					String key = words[i].toLowerCase();
    					if (key.length() > 0) { 
    						if (map.get(key) == null) { 
    							map.put(key, 1);
    						} else { 
    							int times = map.get(key).intValue();
    							times++;
    							map.put(key, times);
    						}
    					}
    				}
    			}
    			Set<Map.Entry<String, Integer>> entrySet = map.entrySet();
    			System.out.println("=====根据单词字母排序=====");
    			for (Map.Entry<String, Integer> entry : entrySet) { 
    				System.out.println(entry.getKey() + " 在API文档中出现了 " + entry.getValue() + " 次");
    			}
    		} catch (IOException e) { 
    			e.printStackTrace();
    		}
    	}
    
    	// 计算单词的出现次数,依据次数排序
    	public static void countWordOrderByCount() throws FileNotFoundException { 
    		BufferedReader br = null;
    		try { 
    			br = new BufferedReader(new FileReader(new File(filename)));
    			String inputLine = null;
    			TreeMap<String, Integer> map = new TreeMap<String, Integer>();
    			while ((inputLine = br.readLine()) != null) { 
    				String[] words = inputLine.split("[ \n\t\r.,;:!?(){}]");
    				for (int i = 0; i < words.length; i++) { 
    					String key = words[i].toLowerCase();
    					if (key.length() > 0) { 
    						if (map.get(key) == null) { 
    							map.put(key, 1);
    						} else { 
    							int times = map.get(key).intValue();
    							times++;
    							map.put(key, times);
    						}
    					}
    				}
    			}
    
    			List<Map.Entry<String, Integer>> list = new ArrayList<Map.Entry<String, Integer>>(map.entrySet());
    			Collections.sort(list, new Comparator<Map.Entry<String, Integer>>() { 
    				public int compare(Entry<String, Integer> o1, Entry<String, Integer> o2) { 
    					return o2.getValue().compareTo(o1.getValue());
    				}
    			});
    			System.out.println("=====根据单词频率排序=====");
    			for (Map.Entry<String, Integer> mapping : list) { 
    				System.out.println(mapping.getKey() + " 在API文档中出现了 " + mapping.getValue() + " 次");
    			}
    		} catch (IOException e) { 
    			e.printStackTrace();
    		}
    	}
    }

输出结果前部分截图为；

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc1MDIxMg_size_16_color_FFFFFF_t_70 1]

[https_docs.oracle.com_javase_8_docs_api]: https://docs.oracle.com/javase/8/docs/api/
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc1MDIxMg_size_16_color_FFFFFF_t_70]: /images/20220402/2b398c02d81749969809d93f79d59b3e.png
[20181226204615648.png]: /images/20220402/6bed0ae15ceb4f858f42e7d3b059042a.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc1MDIxMg_size_16_color_FFFFFF_t_70 1]: /images/20220402/69ae9c3828ef440fb1df58ecdc43e4b1.png