flatxmlbudget.java

随书的代码

import java.io.*;
import java.util.*;


public class FlatXMLBudget {

  public static void convert(List data, OutputStream out) 
   throws IOException {
      
    Writer wout = new OutputStreamWriter(out, "UTF8"); 
    wout.write("<?xml version=\"1.0\"?>\r\n");
    wout.write("<Budget>\r\n");
          
    Iterator records = data.iterator();
    while (records.hasNext()) {
      wout.write("  <LineItem>\r\n");
      Map record = (Map) records.next();
      Set fields = record.entrySet();
      Iterator entries = fields.iterator();
      while (entries.hasNext()) {
        Map.Entry entry = (Map.Entry) entries.next();
        String name = (String) entry.getKey();
        String value = (String) entry.getValue();
        // some of the values contain ampersands and less than
        // signs that must be escaped
        value = escapeText(value);
        
        wout.write("    <" + name + ">");
        wout.write(value);        
        wout.write("</" + name + ">\r\n");
      }
      wout.write("  </LineItem>\r\n");
    }
    wout.write("</Budget>\r\n");
    wout.flush();
        
  } 

  public static String escapeText(String s) {
   
    if (s.indexOf('&') != -1 || s.indexOf('<') != -1 
     || s.indexOf('>') != -1) {
      StringBuffer result = new StringBuffer(s.length() + 4);
      for (int i = 0; i < s.length(); i++) {
        char c = s.charAt(i);
        if (c == '&') result.append("&amp;");
        else if (c == '<') result.append("&lt;");
        else if (c == '>') result.append("&gt;");
        else result.append(c);
      }
      return result.toString();  
    }
    else {
      return s;   
    }
        
  }

  public static void main(String[] args) {
  
    try {
        
      if (args.length < 1) {
       System.out.println("Usage: FlatXMLBudget infile outfile");
       return;
      }
      
      InputStream in = new FileInputStream(args[0]); 
      OutputStream out; 
      if (args.length < 2) {
        out = System.out;
      }
      else {
        out = new FileOutputStream(args[1]); 
      }

      List results = BudgetData.parse(in);
      convert(results, out);
    }
    catch (IOException e) {
      System.err.println(e);       
    }
  
  }

}