Spring EL supports regular expression using a simple keyword “matches“, which is really awesome! For examples, @Value("#{‘100’ matches ‘\\d+’ }") private boolean isDigit; It test whether ‘100‘ is a valid digit via regular expression ‘\\d+‘. Spring EL in Annotation See following Spring EL regular expression examples, some mixed with ternary operator, which makes Spring EL […]
Spring EL supports ternary operator , perform “if then else” conditional checking. For example, condition ? true : false Spring EL in Annotation Spring EL ternary operator with @Value annotation. In this example, if “itemBean.qtyOnHand” is less than 100, then set “customerBean.warning” to true, else set it to false. package com.mkyong.core; import org.springframework.beans.factory.annotation.Value; import org.springframework.stereotype.Component; […]
Spring expression language (SpEL) allow developer uses expression to execute method and inject the method returned value into property, or so called “SpEL method invocation“. Spring EL in Annotation See how to do Spring EL method invocation with @Value annotation. package com.mkyong.core; import org.springframework.beans.factory.annotation.Value; import org.springframework.stereotype.Component; @Component("customerBean") public class Customer { @Value("#{‘mkyong’.toUpperCase()}") private String name; […]
Spring expression language (SpEL) supports many functionality, and you can test those expression features with this special “ExpressionParser” interface. Here’s two code snippets, show the basic usage of using Spring EL. SpEL to evaluate the literal string expression. ExpressionParser parser = new SpelExpressionParser(); Expression exp = parser.parseExpression("’put spel expression here’"); String msg = exp.getValue(String.class); SpEL […]
The Spring EL is similar with OGNL and JSF EL, and evaluated or executed during the bean creation time. In addition, all Spring expressions are available via XML or annotation. In this tutorial, we show you how to use Spring Expression Language(SpEL), to inject String, integer and bean into property, both in XML and annotation. […]
In Spring, @Qualifier means, which bean is qualify to autowired on a field. See following scenario : Autowiring Example See below example, it will autowired a “person” bean into customer’s person property. package com.mkyong.common; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.beans.factory.annotation.Qualifier; public class Customer { @Autowired private Person person; //… } But, two similar beans “com.mkyong.common.Person” are declared […]
In Spring, “Autowiring by AutoDetect“, means chooses “autowire by constructor” if default constructor (argument with any data type), otherwise uses “autowire by type“. See an example of Spring “auto wiring by autodetect”. Auto wiring the “kungfu” bean into “panda”, via constructor or type (base on the implementation of panda bean). <bean id="panda" class="com.mkyong.common.Panda" autowire="autodetect" /> […]
In Spring, “Autowiring by Constructor” is actually autowiring by Type in constructor argument. It means, if data type of a bean is same as the data type of other bean constructor argument, auto wire it. See a full example of Spring auto wiring by constructor. 1. Beans Two beans, developer and language. package com.mkyong.common; public […]
Uses Spring to dependency inject a bean via constructor. 1. IOutputGenerator An interface and implementation class of it. package com.mkyong.output; public interface IOutputGenerator { public void generateOutput(); } package com.mkyong.output.impl; import com.mkyong.output.IOutputGenerator; public class JsonOutputGenerator implements IOutputGenerator { public void generateOutput(){ System.out.println("This is Json Output Generator"); } } 2. Helper class A helper class, later […]
In Spring, “Autowiring by Type” means, if data type of a bean is compatible with the data type of other bean property, auto wire it. For example, a “person” bean exposes a property with data type of “ability” class, Spring will find the bean with same data type of class “ability” and wire it automatically. […]
In Spring, “Autowiring by Name” means, if the name of a bean is same as the name of other bean property, auto wire it. For example, if a “customer” bean exposes an “address” property, Spring will find the “address” bean in current container and wire it automatically. And if no matching found, just do nothing. […]
A simple Spring example to show you how to dependency inject a bean via setter method, the most common used DI method. 1. IOutputGenerator An interface and implemntation class of it. package com.mkyong.output; public interface IOutputGenerator { public void generateOutput(); } package com.mkyong.output.impl; import com.mkyong.output.IOutputGenerator; public class CsvOutputGenerator implements IOutputGenerator { public void generateOutput() { […]
This tutorial shows you how to create a simple hello world example in Spring 3.0. Technologies used in this article : Spring 3.0.5.RELEASE Maven 3.0.3 Eclipse 3.6 JDK 1.6.0.13 P.S Spring 3.0, at least JDK 1.5 is required to work. Spring 3.0 dependencies In Spring 2.5.x, almost the entire Spring modules are grouped into a […]
Apache Wicket tutorials with full example, including component, model, form component, custom validator, integrate with Spring and etc…
Java MongoDB tutorials with full example, including install and configure MongoDB, use Java MongoDB driver APIs and also Spring data for MongoDB to perform CRUD operations.
This guide shows you how to install MongoDB on Ubuntu. Ubuntu 12.10 MongoDB 2.2.3 1. Add 10gen package to source.list.d Ubuntu 12 comes with a “mongo” package, but not the latest version. $ sudo apt-cache search mongodb mongodb mongodb-clients mongodb-dev mongodb-server It’s recommended to add 10gen package to /etc/apt/sources.list.d, as it contains the latest stable […]
In Spring data for MongoDB, you can use remove() and findAndRemove() to delete documents from MongoDB. remove() – delete single or multiple documents. findAndRemove() – delete single document, and returns the deleted document. Common Mistake Don’t use findAndRemove() to perform a batch delete (remove multiple documents), only the first document that matches the query will […]
Here we show you a few examples to query documents from MongoDB, by using Query, Criteria and along with some of the common operators. Test Data > db.users.find() { "_id" : ObjectId("id"), "ic" : "1001", "name" : "ant", "age" : 10 } { "_id" : ObjectId("id"), "ic" : "1002", "name" : "bird", "age" : 20 […]
In Spring data – MongoDB, you can use following methods to update documents. save – Update the whole object, if “_id” is present, perform an update, else insert it. updateFirst – Updates the first document that matches the query. updateMulti – Updates all documents that match the query. Upserting – If no document that matches […]
In Spring data MongoDB, you can use save(), insert() to save a or a list of objects into mongoDB database. User user = new User("…"); //save user object into "user" collection / table //class name will be used as collection name mongoOperation.save(user); //save user object into "tableA" collection mongoOperation.save(user,"tableA"); //insert user object into "user" collection […]
In this tutorial, we show you how to use “SpringData for MongoDB” framework, to perform CRUD operations in MongoDB, via Spring’s annotation and XML schema. Updated on 1/04/2013 Article is updated to use latest SpringData v 1.2.0.RELEASE, it was v1.0.0.M2. Tools and technologies used : Spring Data MongoDB – 1.2.0.RELEASE Spring Core – 3.2.2.RELEASE Java […]
MongoDB comes with “com.mongodb.util.JSON” class to convert JSON data directly to a DBObject. For example, data represent in JSON format : { ‘name’ : ‘mkyong’, ‘age’ : 30 } To convert it to DBObject, you can code like this : DBObject dbObject = (DBObject) JSON.parse("{‘name’:’mkyong’, ‘age’:30}"); Example See a full example to convert above JSON […]
In this tutorial, we show you how to save an image file into MongoDB, via GridFS API. The GridFS APIs are able to serve other binary files as well, like video and music files. Note For detail explanation, read this MongoDB GridFS manual. 1. Save image Code snippets to save an image file into MongoDB, […]
In this tutorial, we show you how to use Java MongoDB API collection.update() to update documents. Test Data Assume following data / documents are inserted. { "hosting" : "hostA", "type" : "vps", "clients" : 1000 }, { "hosting" : "hostB", "type" : "dedicated server", "clients" : 100 }, { "hosting" : "hostC", "type" : "vps", […]
In this tutorial, we show you few common ways to get or query document from collection. Test Data Insert 5 dummy documents for testing. { "_id" : { "$oid" : "id"} , "number" : 1 , "name" : "mkyong-1"} { "_id" : { "$oid" : "id"} , "number" : 2 , "name" : "mkyong-2"} { […]
In this tutorial, we show you how to use collection.remove() to delete documents from the collection. 1. Test Data Insert 10 documents from number 1 to 10 for testing. for (int i=1; i <= 10; i++) { collection.insert(new BasicDBObject().append("number", i)); } 2. DBCollection.remove() See below code snippets to delete documents. Example 1 Get first document […]
In this tutorial, we show you 4 ways to insert below JSON data into a “document“, via Java MongoDB API. Test Data Test data in JSON format. { "database" : "mkyongDB", "table" : "hosting", "detail" : { records : 99, index : "vps_index1", active : "true" } } } 1. BasicDBObject example BasicDBObject document = […]
In Java, you can use db.getCollection(“your collection name”) to get a single collection to use. DBCollection collection = db.getCollection("yourCollection"); If you do not know the collection name, use db.getCollectionNames() to get the entire list of collection names from a selected database. DB db = mongo.getDB("yourdb"); Set<String> collections = db.getCollectionNames(); for (String collectionName : collections) { […]
When Staring the mongoDB server, it hits below errors, and the mongoDB server is unable to start. ************** old lock file: \data\db\mongod.lock. probably means unclean shutdown recommend removing file and running –repair see: http://dochub.mongodb.org/core/repair for more information ************* Mon May 09 12:37:43 [initandlisten] exception in initAndListen std::exception: old lock file, terminating Mon May 09 12:37:43 […]
By default, MongoDB is run in trust environment (authentication with a username and password is NOT required). In this tutorial, we will show you how to start MongoDB in secure mode / enable authentication, and connect with the Java MongoDB driver. 1. Start MongoDB in Secure Mode Start MongoDB with –auth option, now, MongoDB need […]
A simple Java + MongoDB hello world example – how to connect, create database, collection and document, save, update, remove, get and display document (data). Tools and technologies used : MongoDB 2.2.3 MongoDB-Java-Driver 2.10.1 JDK 1.6 Maven 3.0.3 Eclipse 4.2 P.S Maven and Eclipse are both optional, just my personal favorite development tool. 1. Create […]
In Java, we can use String.valueOf() to convert a char array to a String. JavaSample1.java package com.mkyong.markdown; public class JavaSample1 { public static void main(String[] args) { char[] charArrays = new char[]{‘1’, ‘2’, ‘3’, ‘A’, ‘B’, ‘C’}; String str = new String(charArrays); System.out.println(str); // 123ABC String str2 = String.valueOf(charArrays); System.out.println(str2); // 123ABC } } Output […]
In Java, you can use String.toCharArray() to convert a String into a char array. StringToCharArray.java package com.mkyong.utils; public class StringToCharArray { public static void main(String[] args) { String password = "password123"; char[] passwordInCharArray = password.toCharArray(); for (char temp : passwordInCharArray) { System.out.println(temp); } } } Output p a s s w o r d 1 […]
MongoDB didn’t provides any command to create “database“. Actually, you don’t need to create it manually, because, MangoDB will create it on the fly, during the first time you save the value into the defined collection (or table in SQL), and database. For developer from SQL background, we need to create a database, table and […]
This Article is outdated! Please refer to this latest guide to install MongoDB as Windows Service. A guide to show you how to installed MongoDB on Windows. 1. mongod –help Get to know all the Windows service related commands by typing “mongod –help“. C:\MongoDB\bin>mongod –help Windows Service Control Manager options: –install install mongodb service –remove […]
In this tutorial, we will show you how to install MongoDB on Windows. MongoDB 2.2.3 Windows 7 Note The MongoDB does not require installation, just download and extracts the zip file, configure the data directory and start it with command “mongod“. 1. Download MongoDB Download MongoDB from official MongoDB website. Choose Windows 32 bits or […]
Hibernate component represents as a group of values or properties, not entity (table). See following tutorial to understand how component works in Hibernate. 1. Customer Table See below customer table. Customer table, SQL script in MySQL database. CREATE TABLE `customer` ( `CUST_ID` int(10) unsigned NOT NULL AUTO_INCREMENT, `CUST_NAME` varchar(10) NOT NULL, `AGE` int(10) unsigned NOT […]
In this tutorial, we show you how to use Hibernate to implements “many-to-many table relationship, with extra column in the join table“. Note For many to many relationship with NO extra column in the join table, please refer to this @many-to-many tutorial 1. Many-to-many table + extra columns in join table The STOCK and CATEGORY […]
In this tutorial, it will reuse the entire infrastructure of the previous “Hibernate many to many example – XML mapping” tutorial, enhance it to support Hibernare / JPA annotation. Note For many to many with extra columns in join table, please refer to this tutorial. Project Structure Review the new project structure of this tutorial. […]
Problem A table named “category” in MySQL database, contains a “DESC” keyword as column name. CREATE TABLE `category` ( `CATEGORY_ID` int(10) unsigned NOT NULL AUTO_INCREMENT, `NAME` varchar(10) NOT NULL, `DESC` varchar(255) NOT NULL, PRIMARY KEY (`CATEGORY_ID`) USING BTREE ); Hibernate XML mapping file <hibernate-mapping> <class name="com.mkyong.stock.Category" table="category" catalog="mkyongdb"> … <property name="desc" type="string"> <column name="DESC" not-null="true" […]
