在Java中使用StringTokenizer以显示文件中选定的内容

Question

可以任何人建议，如何使用 string-tokens 在 java 中，以读取文件中的所有数据，仅显示显示它的一些内容。就像，如果我有

apple = 23456, mango = 12345, orange= 76548, guava = 56734

我需要选择Apple，并且应在输出中显示与Apple相对应的值。

这是代码

import java.io.BufferedReader;
import java.io.FileReader;
import java.util.StringTokenizer;
public class ReadFile {
public static void main(String[] args) {
try { 
String csvFile = "Data.txt";
   //create BufferedReader to read csv file
   BufferedReader br = new BufferedReader(new FileReader(csvFile));
   String line = "";
   StringTokenizer st = null;
   int lineNumber = 0; 
   int tokenNumber = 0;
   //read comma separated file line by line
   while ((line = br.readLine()) != null) {
     lineNumber++;
     //use comma as token separator
     st = new StringTokenizer(line, ",");
     while (st.hasMoreTokens()) {
       tokenNumber++;
       //display csv values
       System.out.print(st.nextToken() + "  ");
     }
     System.out.println();
     //reset token number
     tokenNumber = 0;
   }
  } catch (Exception e) {
   System.err.println("CSV file cannot be read : " + e);
  }
  }   
  }

这是我正在处理的文件：

ImageFormat=GeoTIFF
ProcessingLevel=GEO
ResampCode=CC
NoScans=10496
NoPixels=10944
MapProjection=UTM 
Ellipsoid=WGS_84
Datum=WGS_84
MapOriginLat=0.00000000
MapOriginLon=0.00000000
ProdULLat=18.54590200
ProdULLon=73.80059300
ProdURLat=18.54653200
ProdURLon=73.90427600
ProdLRLat=18.45168500
ProdLRLon=73.90487900
ProdLLLat=18.45105900
ProdLLLon=73.80125300
ProdULMapX=373416.66169100
ProdULMapY=2051005.23286800
ProdURMapX=384360.66169100
ProdURMapY=2051005.23286800
ProdLRMapX=373416.66169100
ProdLRMapY=2040509.23286800
ProdLLMapX=384360.66169100
ProdLLMapY=2040509.23286800

从中，我只需要显示以下内容： Noscans nopixels Produllat Produllon Prodlrlat prodlrlon

Answer 1

public class Test {
  public String getValue(String str, String strDelim, String keyValueDelim, String key){
      StringTokenizer tokens = new StringTokenizer(str, strDelim);
      String sentence;
      while(tokens.hasMoreElements()){
          sentence = tokens.nextToken();
          if(sentence.contains(key)){
             return sentence.split(keyValueDelim)[1];
          }
       }        
     return  null;
   }
  public static void main(String[] args) {
    System.out.println(new Test().getValue("apple = 23456, mango = 12345, orange= 76548, guava = 56734", ",", "=", "apple"));
  }
}

"我注意到您已经编辑了您的问题并添加了代码。对于新版本问题，您仍然可以在读取文件中的字符串并获取您的欲望值时简单地调用方法！"

Answer 2

我已经写了代码，假设您已经将数据从文件存储到字符串，

public static void main(String[] args) {
    try {
        String[] CONSTANTS = {"apple", "guava"};
        String input = "apple = 23456, mango = 12345, orange= 76548, guava = 56734";
        String[] token = input.split(",");
        for(String eachToken : token) {
            String[] subToken = eachToken.split("=");
            // checking whether this data is required or not. 
            if(subToken[0].trim().equals(CONSTANTS[0]) || subToken[0].trim().equals(CONSTANTS[1])) {
                System.out.println("No Need to do anything");
            } else {
                System.out.println(subToken[0] + " " + subToken[1]);
            }
        }
    } catch(Exception e) {
        e.printStackTrace();
    }
}

Answer 3

使用BufferedReader读取完整的行，并将其传递给stringTokenizer用令牌为" =" [[如您在文件中所述]。

有关更多信息，请粘贴您的文件以及您到目前为止尝试的内容。

ArrayList<String> list = new ArrayList<String>();
list.add("NoScans");
list.add("NoPixels");
list.add("ProdULLat");
list.add("ProdULLon");
list.add("ProdLRLat");
list.add("ProdLRLon");
//read a line from a file.
    while ((line = br.readLine()) != null) {
         lineNumber++;
         //use 'equal to' as token separator
         st = new StringTokenizer(line, "=");
         //check for tokens from the above string tokenizer.
         while (st.hasMoreTokens()) {
         String key = st.nextToken(); //this will give the first token eg: NoScans
         String value = st.nextToken(); //this will give the second token eg:10496
         //check the value is present in the list or not. If it is present then print 
         //the value else leave it as it is.
         if(list.contains(key){
          //display csv values
           System.out.print(key+"="+ " "+value);
           }
         }