Java file reading and converting using regular expression

Question

Hi I have text file which contain given below

 PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND            
23876 root      20   0  9436 1764  760 R    4  0.0   0:00.08 top                
50741 hcsadm    20   0 18.0g 2.3g 751m S    4  0.4   1310:10 hdbnameserver      
51089 hcsadm    20   0 55.0g  48g  23g S    4  9.5   4713:14 hdbindexserver     
15618 gdm       20   0  273m  65m  11m S    2  0.0 162:17.68 gdm-simple-gree    
15938 cisadm    20   0  687m 281m 267m S    2  0.1 306:55.97 hdb.sapCIS_HDB0    
17645 hbsadm    20   0 18.1g 7.7g 598m S    2  1.5 974:48.98 hdbnameserver      
17795 hbsadm    20   0  109g 104g  39g S    2 20.8  14496:26 hdbindexserver

and my java code reading file as given below

 Scanner sc = new Scanner(new File("top.txt"));
 while(sc.hasNext()){
  String line = sc.nextLine();       
 }

Now any one knows how to I translate file data in following format

array=[{PID:23876,USER:root,COMMAND:top},{PID:50741,USER:hcsadm,COMMAND:hdbnameserver},..........]

How I used regular expression in java so I convert my file info in above format or there are any other options in java to make above array.

Do you want a JSON string that represents the file contents? Or is your proposed output a conceptual representation of a Java data structure? Because arrays don't look like that in Java. — Ted Hopp
– Ted Hopp, Commented Sep 18, 2013 at 7:32
@TedHopp Hi, actually I want json string so I insert that json string in mongo. — Neo-coder
– Neo-coder, Commented Sep 18, 2013 at 13:44
Use one of the posted solutions to parse each line (skipping the first line, of course) and use a JSON library to build the appropriate JSON structures. If you have J2EE 7, you can use the classes in javax.json. Alternatively, you can use a third-party package like the lightweight json-simple or the popular JSON in Java library. Many other Java libraries are listed at json.org. — Ted Hopp
– Ted Hopp, Commented Sep 18, 2013 at 18:05

Rafi Kamal · Accepted Answer · 2013-09-18 07:33:51Z

2

Just split each line.

String[] fields = line.split("\\s+"); // split based on whitespace characters
String PID = fields[0];
String USER = fields[1];
String COMMAND= fields[11];

answered Sep 18, 2013 at 7:33

Rafi Kamal

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Nir Alfasi · Accepted Answer · 2013-09-18 07:34:57Z

2

Try:

while(sc.hasNext()){
  String line = sc.nextLine();       
  String[] values = line.split("\\s+");
  String PID = "PID":+values[0];
  String USER = "USER:"+values[1];
  String COMMAND = "COMMAND:"+values[11];
  //now do whatever you want with it, for example
  String [] res = {PID, USER, COMMAND};
 }

answered Sep 18, 2013 at 7:34

Nir Alfasi

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