Java parse common data files
Java parse common data files such as csv, json, yaml, xml, ini, properties and etc.
Java read csv with javacsv.jar
- Csv file example:
host,username,password
1.1.1.1,admin,admin123
1.1.1.2,root,root123- Java code to read data from csv file:
try
{
CsvReader cr = new CsvReader("tmp/test.csv");
// 1. read csv headers - assuming first row is header record
if (cr.readHeaders())
{
String[] headers = cr.getHeaders();
for (String header: headers)
{
System.out.print(header + " ");
}
System.out.println();
}
System.out.println("***Done reading headers***");
// 2. read csv records
while (cr.readRecord())
{
String[] record = cr.getValues();
for (String column: record)
{
System.out.print(column + " ");
}
System.out.println();
}
System.out.println("***Done reading records***");
cr.close();
}
catch (Exception e)
{
e.printStackTrace();
}Java read json with gson
- Json file example:
{
"host": "www.google.com",
"creds": [
{
"user": "admin",
"pass": "admin123"
},
{
"user": "test",
"pass": "test123"
}
]
}- Java code to read all member values:
try
{
JsonParser jp = new JsonParser();
JsonElement je = jp.parse(new FileReader("tmp/test.json"));
JsonObject jo = je.getAsJsonObject();
// 1. get value
System.out.println(jo.get("host"));
// 2. get list of values
JsonArray ja = jo.get("creds").getAsJsonArray();
Iterator<JsonElement> jes = ja.iterator();
while (jes.hasNext())
{
JsonElement jsonElement = jes.next();
JsonObject jsonObject = jsonElement.getAsJsonObject();
System.out.println(jsonObject.get("user"));
System.out.println(jsonObject.get("pass"));
}
}
catch (Exception e)
{
e.printStackTrace();
}Java read yaml with snakeyaml
- Yaml file example:
host: www.google.com
creds:
- user: admin
pass: admin123
- user: test
pass: test123- Java code to read all member values:
try
{
Yaml yaml = new Yaml();
Map<String, Object> data = (Map<String, Object>)yaml.load(new FileReader("tmp/test.yml"));
// 1. get value
System.out.println(data.get("host"));
// 2. get list of values
List<Map> creds = (List<Map>)data.get("creds");
for (Map cred: creds)
{
System.out.println(cred.get("user"));
System.out.println(cred.get("pass"));
}
}
catch (Exception e)
{
e.printStackTrace();
}Java read xml with javax.xml.parsers.* or dom4j
- Xml file example:
<task>
<step>
<command>passwd root</command>
<expect>password:</expect>
</step>
<step>
<command>root123</command>
<expect>password:</expect>
</step>
<step>
<command>root123</command>
<expect>successfully.</expect>
</step>
</task>- Java read the shell sequence using DOM parser:
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
try
{
DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
Document document = documentBuilder.parse(new File("tmp/test.xml"));
NodeList nodeList = document.getElementsByTagName("step");
for (int i=0; i<nodeList.getLength(); i++)
{
Node node = nodeList.item(i);
NodeList childNodeList = node.getChildNodes();
for (int j=0; j<childNodeList.getLength(); j++)
{
Node leafNode = childNodeList.item(j);
if (leafNode.getNodeName().equalsIgnoreCase("COMMAND"))
{
System.out.println("COMMAND: " + leafNode.getTextContent());
}
if (leafNode.getNodeName().equalsIgnoreCase("EXPECT"))
{
System.out.println("EXPECT: " + leafNode.getTextContent());
}
}
}
}
catch (Exception e)
{
e.printStackTrace();
}- Java read the shell sequence using SAX parser:
import org.xml.sax.Attributes;
import org.xml.sax.helpers.DefaultHandler;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
public static void main(String[] args)
{
try
{
SAXParserFactory saxParserFactory = SAXParserFactory.newInstance();
SAXParser saxParser = saxParserFactory.newSAXParser();
saxParser.parse(new File("tmp/test.xml"), new MySaxHandler());
}
catch (Exception e)
{
e.printStackTrace();
}
}
static class MySaxHandler extends DefaultHandler
{
boolean isCommand = false;
boolean isExpect = false;
@Override
public void startElement(String uri, String localName, String qName, Attributes attributes)
{
if (qName.equalsIgnoreCase("command"))
{
isCommand = true;
}
if (qName.equalsIgnoreCase("expect"))
{
isExpect = true;
}
}
@Override
public void characters(char[] ch, int start, int length)
{
if (isCommand)
{
System.out.println("COMMAND: " + new String(ch, start, length));
isCommand = false;
}
if (isExpect)
{
System.out.println("EXPECT: " + new String(ch, start, length));
isExpect = false;
}
}
}Java read ini file with ini4j
- Ini file example:
[web]
host=1.1.1.1
username=admin
password=admin123
[db]
host=1.1.1.2
username=root
password=root123- Java code to read config from ini file:
try
{
Ini ini = new Ini(new File("tmp/test.ini"));
System.out.println("Reading web config...");
System.out.println(ini.get("web", "host"));
System.out.println(ini.get("web", "username"));
System.out.println(ini.get("web", "password"));
System.out.println("Reading db config...");
System.out.println(ini.get("db", "host"));
System.out.println(ini.get("db", "username"));
System.out.println(ini.get("db", "password"));
}
catch (Exception e)
{
e.printStackTrace();
}Java read properties file with Properties:
- Properties file example:
web.host = 1.1.1.1
web.username = admin
web.password = admin123
db.host = 1.1.1.2
db.username = root
db.password = root123- Java code to read config from properties file:
try
{
Properties properties = new Properties();
properties.load(new FileReader("tmp/test.properties"));
System.out.println("Reading web config...");
System.out.println(properties.get("web.host"));
System.out.println(properties.get("web.username"));
System.out.println(properties.get("web.password"));
System.out.println("Reading db config...");
System.out.println(properties.get("db.host"));
System.out.println(properties.get("db.username"));
System.out.println(properties.get("db.password"));
}
catch (Exception e)
{
e.printStackTrace();
}