Java Restful Service Tutorial - Connect to a database

Java Restful Service Tutorial - Connect to a database - Part 3

Java Restful Service Tutorial - Creating a rest service - Part 2

  Jersey framework - http://jersey.java.net

  Jackson framework - http://jackson.codehaus.org

  @Path("/v1/status/*") //it is good practice to conclude the version information in the path

  @Path could be nested by declaring in the class level or method level

  @GET

  @POST used to submit data like Loing pages with HTTPS you can protect the data

  @PUT used mainly for updating data but can be used for inserting/adding data

  @DELETE

  @HEAD used to return meta-data of the resource

  @Produces it could be in the class level to be treated as a default

  @Consumes 1st, it is used with @POST most commonly; 2nd, you can define your own or used the predufine MediaType

  3rd, The body will be brought into the java code as a String called message

  Example of Database Status

  Objective: to create a URL that will check our database connection

  <localhost:7001/console> is the admin Console for Weblogic;

  then goto the resource panel and create a new database resource; then note down the JNDI name for the data source;

  to write a DAO java file; first new InitialContext(); then context.lookup("JNDI Name");

  conn=datasource.getConnection();

  query=conn.prepareStatement("select * from dual");

  ResultSet rs = query.executeQuery();

  while(rs.next()) {rs.getString(DataTIme)}; query.close() which shoudl be in the finally block;

Java Restful Service Tutorial - Short intro video - Part 1

  Use HTTP methods explicityly

  Expose directory structure- like URIs

  Transfer XML JavaScript Object NOnotation or bnoth

  be stateless

  There are plenty of reasons to use it:

  SImpler thatn SOAP

  more expressive, HUman readable results

  Can send XML JSON

Java Restful Service Tutorial - Creating Search functionality - Part 4

  //jsonlint.com is a website to validate the JSON format

  import org.codehaus.jettison.json.*

  if w have multi rows, we wanti it organized, so it is easy to  search through

  the JSON come into play

    Key     Colon  Value 

  {

  "PC_PARTS_PK":"primary key"

  "PC_PARTS_TITLE":"product name"

  "PC_PARTS_CODE":"product ID code"

  }

  JASON Object Example of Single Row

  {

  "PC_PARTS_PK":"1"

  "PC_PARTS_TITLE":"Intel MB"

  "PC_PARTS_CODE":"123456"

  }

  

  JASON Object Example of multi Rows using JASON array

  {

   {

   "PC_PARTS_PK":"1"

   "PC_PARTS_TITLE":"Intel MB"

   "PC_PARTS_CODE":"123456"

   },

   {

   "PC_PARTS_PK":"2"

   "PC_PARTS_TITLE":"Intel MB"

   "PC_PARTS_CODE":"456789"

   }

  }

  //ToJson.java, this class could be also rewriten to be a static Java class

  //why do they throws excpetions

  public JSONArray toJSONArrya(ResultSet rs) throws exception

  {

  JSONArray json=new JSONArray();

  rs.getMetaData() is used to get the information regarding column name, row counts etc,;

  rs.getMetaData().getColumnCount() is used to get the row counts;

  JSONObject obj= new JSONObject();

  obj.put(column_name,rs.getObject(column_name))

  json.put(obj)

  

  //V1_inventory.java

  //The response object(recommanded) is telling Jersey that we want to customize the http response

  public Response returnAllPcParts() throws Exception{

  //The direct return java type will delegate it to Jersey

  public String  returnAllPcParts() throws Exception{

  ResultSet rs= query.executoQuery();

  ToJson converter = new ToJSON();

  JSONArray json= new JSONArray();

  json=converter.toJSONArray(rs);

  Senior Systems Engineer = json.toString();

  return Senior Systems Engineer;

  

  This series is about learning and bulding your own converter will helpo you

  understand how JSON works and how easy it is to use;

  

  when you use a rdr pary tool, it usually hard to modify it;

  if you build your own, it simple to change it when needed.