\nSo, let’s start the Spring Annotation Tutorial.<\/p>\n
![\"Spring](\"https:\/\/data-flair.training\/blogs\/wp-content\/uploads\/sites\/2\/2018\/07\/Spring-Annotation-Based-Configuration-01.jpg\")
<\/a>Spring Annotation Based Configuration – Types with Example<\/p><\/div>\n
2. What is Spring Annotation Based Configuration?<\/h2>\n
In Spring Framework annotation-based configuration instead of using XML for describing the bean wiring, you have the choice to move the bean configuration into component class. It is done by using annotations on the relevant class, method or the field declaration. Before performing XML, injection annotation injection is performed. Therefore, the latter one will override the former configuration for the properties. Once the tag <context:annotation-config\/><\/strong> is configured you have the authority to start annotating your code. It will indicate that the Spring should automatically wire the values into properties methods and constructors.<\/p>\n Here, we discussed some of the important Spring annotations:<\/p>\n Spring @Required annotation is applicable to bean property setter methods. It indicates that the affected bean property must be populated in the XML config file at the time of configuration. Let’s discuss Spring BeanPostProcessors – Latest Tutorial 2018<\/a><\/strong> Following is the code for MainApp.java file:<\/strong><\/p>\n The content for the configuration file Beans.xml is as defined:<\/strong><\/p>\n The above example will produce the following message as output: The Spring @Autowired annotation gives you more fine-grained control over how and where the autowiring of it should be accomplished. Similar to the @Required annotation this Spring annotation can also be used for autowiring the bean on the setter method. You have the power of using the @Autowired annotation on setter methods to get rid of the <property> in the XML. The code for the java file TextEditor:<\/strong><\/p>\n The content of SpellChecker.java:<\/strong><\/p>\n The java file MainApp.java is as defined:<\/strong><\/p>\n The Bean.xml configuration file is as follows:<\/strong><\/p>\n Do you know Spring Java Based Configuration – How to Configure Spring Beans<\/a><\/strong> There will be a situation where you will create more than one bean of the same type. But you will want to wire only one of them with the property. For those cases, you have to use @Qualifier annotation in Spring with @Autowired so as to remove the confusion by specifying the bean for wiring. The code for Student.java:<\/strong><\/p>\n The content for java file Profile:<\/strong><\/p>\n The MainApp.java is as defined:<\/strong><\/p>\n Let’s see Spring MVC Framework – Integration of MVC with Spring<\/a><\/strong> Once you are done creating the above files run the application. The following message will be displayed as output:
\nRead More about\u00a0Spring Beans Autowiring Eclipse IDE Example<\/a><\/strong>
\nBy default, Spring annotation wiring is not turned on in Spring Framework. Therefore, you need to enable it before you can use the Spring annotation-based wiring in the Spring Configuration file. Below is the configuration file in case you want to use annotation in your application:<\/p>\n<?xml version = \"1.0\" encoding = \"UTF-8\"?>\r\n<beans xmlns = \"http:\/\/www.springframework.org\/schema\/beans\"\r\n xmlns:xsi = \"http:\/\/www.w3.org\/2001\/XMLSchema-instance\"\r\n xmlns:context = \"http:\/\/www.springframework.org\/schema\/context\"\r\n xsi:schemaLocation = \"http:\/\/www.springframework.org\/schema\/beans\r\n http:\/\/www.springframework.org\/schema\/beans\/spring-beans-3.0.xsd\r\n http:\/\/www.springframework.org\/schema\/context\r\n http:\/\/www.springframework.org\/schema\/context\/spring-context-3.0.xsd\">\r\n <context:annotation-config\/>\r\n <!-- bean definitions go here -->\r\n<\/beans><\/pre>\n
3. Spring Annotation List<\/h2>\n
\n
a. @Required Annotation in Spring<\/h3>\n
\nLet\u2019s define a working example of\u00a0@Required Spring annotation using Eclipse IDE having the following steps:
\nCreate your project with name SpringEx and a package com.example. This should be under the src folder of your created project.<\/p>\n\n
\nThe code for Student.java file:<\/strong><\/p>\npackage com.example;\r\nimport org.springframework.beans.factory.annotation.Required;\r\npublic class Student {\r\n private Integer age;\r\n private String name;\r\n@Required\r\npublic void setAge(Integer age) {\r\n this.age = age;\r\n}\r\npublic Integer getAge() {\r\n return age;\r\n}\r\n@Required\r\npublic void setName(String name) {\r\n this.name = name;\r\n}\r\npublic String getName() {\r\n return name;\r\n }\r\n}<\/pre>\npackage com.example;\r\nimport org.springframework.context.ApplicationContext;\r\nimport org.springframework.context.support.ClassPathXmlApplicationContext;\r\npublic class MainApp {\r\n public static void main(String[] args) {\r\n ApplicationContext context = new\r\nClassPathXmlApplicationContext(\"Beans.xml\");\r\n Student student = (Student) context.getBean(\"student\");\r\n System.out.println(\"Name : \" + student.getName() );\r\n System.out.println(\"Age : \" + student.getAge() );\r\n }\r\n}<\/pre>\n<?xml version = \"1.0\" encoding = \"UTF-8\"?>\r\n<beans xmlns = \"http:\/\/www.springframework.org\/schema\/beans\"\r\n xmlns:xsi = \"http:\/\/www.w3.org\/2001\/XMLSchema-instance\"\r\n xmlns:context = \"http:\/\/www.springframework.org\/schema\/context\"\r\n xsi:schemaLocation = \"http:\/\/www.springframework.org\/schema\/beans\r\n http:\/\/www.springframework.org\/schema\/beans\/spring-beans-3.0.xsd\r\n http:\/\/www.springframework.org\/schema\/context\r\n http:\/\/www.springframework.org\/schema\/context\/spring-context-3.0.xsd\">\r\n<context:annotation-config\/>\r\n<!-- Definition for student bean -->\r\n<bean id = \"student\" class = \"com.example.Student\">\r\n <property name = \"name\" value = \"Hari\" \/>\r\n <property name = \"age\" value = \"11\"\/>\r\n <\/bean>\r\n <\/beans>\r\n<\/pre>\n
\nName: Hari<\/strong>
\nAge: 11<\/strong><\/p>\nb. @Autowired Annotation in Spring<\/h3>\n
\nRead about Spring Bean Life Cycle \u2013 Initialization and Destruction<\/a> <\/strong>
\nLet\u2019s define a working example of@Autowired Spring annotation using Eclipse IDE having the following steps:<\/p>\n\n
package com.example;\r\nimport org.springframework.beans.factory.annotation.Autowired;\r\npublic class TextEditor {\r\n private SpellChecker spellChecker;\r\n @Autowired\r\npublic void setSpellChecker( SpellChecker spellChecker ){\r\n this.spellChecker = spellChecker;\r\n }\r\npublic SpellChecker getSpellChecker( ) {\r\n return spellChecker;\r\n}\r\npublic void spellCheck() {\r\n spellChecker.checkSpelling();\r\n }\r\n}<\/pre>\npackage com.example;\r\npublic class SpellChecker {\r\n public SpellChecker(){\r\n System.out.println(\"Inside SpellChecker constructor.\" );\r\n}\r\npublic void checkSpelling(){\r\n System.out.println(\"Inside checkSpelling.\" );\r\n }\r\n}<\/pre>\npackage com.example;\r\nimport org.springframework.context.ApplicationContext;\r\nimport org.springframework.context.support.ClassPathXmlApplicationContext;\r\npublic class MainApp {\r\npublic static void main(String[] args) {\r\nApplicationContext context = new ClassPathXmlApplicationContext(\"Beans.xml\");\r\nTextEditor te = (TextEditor) context.getBean(\"textEditor\");\r\nte.spellCheck();\r\n}\r\n}<\/pre>\n<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n<beans xmlns=\"http:\/\/www.springframework.org\/schema\/beans\"\r\n xmlns:xsi=\"http:\/\/www.w3.org\/2001\/XMLSchema-instance\"\r\n xmlns:context=\"http:\/\/www.springframework.org\/schema\/context\"\r\n xsi:schemaLocation=\"http:\/\/www.springframework.org\/schema\/beans\r\n http:\/\/www.springframework.org\/schema\/beans\/spring-beans.xsd\r\n http:\/\/www.springframework.org\/schema\/context\r\n http:\/\/www.springframework.org\/schema\/context\/spring-context.xsd\">\r\n <context:annotation-config\/>\r\n <!-- Definition for textEditor bean without constructor-arg -->\r\n <bean id=\"textEditor\" class=\"com.example.TextEditor\"><\/bean>\r\n <!-- Definition for spellChecker bean -->\r\n <bean id=\"spellChecker\" class=\"com.example.SpellChecker\"><\/bean>\r\n<\/beans><\/pre>\n
\nOnce you are done with these then run the application. You will see the following as the message as output:
\nInside SpellChecker constructor.<\/strong>
\nInside checkSpelling.<\/strong><\/p>\nc. @Qualifier Annotation in Spring<\/h3>\n
\nLet\u2019s define a working example of @Qualifier Spring annotation using Eclipse IDE having the following steps:<\/p>\n\n
package com.example;\r\npublic class Student {\r\n private Integer age;\r\n private String name;\r\npublic void setAge(Integer age) {\r\n this.age = age;\r\n}\r\npublic Integer getAge() {\r\n return age;\r\n}\r\npublic void setName(String name) {\r\n this.name = name;\r\n}\r\npublic String getName() {\r\n return name;\r\n }\r\n}<\/pre>\npackage com.example;\r\nimport org.springframework.beans.factory.annotation.Autowired;\r\nimport org.springframework.beans.factory.annotation.Qualifier;\r\npublic class Profile {\r\n @Autowired\r\n @Qualifier(\"student1\")\r\n private Student student;\r\n public Profile(){\r\n System.out.println(\"Inside Profile constructor.\" );\r\n}\r\npublic void printAge() {\r\n System.out.println(\"Age : \" + student.getAge() );\r\n}\r\npublic void printName() {\r\n System.out.println(\"Name : \" + student.getName() );\r\n }\r\n}<\/pre>\npackage com.example;\r\nimport org.springframework.context.ApplicationContext;\r\nimport org.springframework.context.support.ClassPathXmlApplicationContext;\r\npublic class MainApp {\r\n public static void main(String[] args) {\r\n ApplicationContext context = new ClassPathXmlApplicationContext(\"Beans.xml\");\r\n Profile profile = (Profile) context.getBean(\"profile\");\r\n profile.printAge();\r\n profile.printName();\r\n }\r\n }<\/pre>\n
\nThe Beans.xml is as follows:<\/strong><\/p>\n<?xml version = \"1.0\" encoding = \"UTF-8\"?>\r\n<beans xmlns = \"http:\/\/www.springframework.org\/schema\/beans\"\r\n xmlns:xsi = \"http:\/\/www.w3.org\/2001\/XMLSchema-instance\"\r\n xmlns:context = \"http:\/\/www.springframework.org\/schema\/context\"\r\n xsi:schemaLocation = \"http:\/\/www.springframework.org\/schema\/beans\r\n http:\/\/www.springframework.org\/schema\/beans\/spring-beans-3.0.xsd\r\n http:\/\/www.springframework.org\/schema\/context\r\n http:\/\/www.springframework.org\/schema\/context\/spring-context-3.0.xsd\">\r\n <context:annotation-config\/>\r\n <!-- Definition for profile bean -->\r\n <bean id = \"profile\" class = \"com.example.Profile\"><\/bean>\r\n <!-- Definition for student1 bean -->\r\n <bean id = \"student1\" class = \"com.example.Student\">\r\n <property name = \"name\" value = \"Hari\" \/>\r\n <property name = \"age\" value = \"11\"\/>\r\n <\/bean>\r\n<!-- Definition for student2 bean -->\r\n<bean id = \"student2\" class = \"com.example.Student\">\r\n <property name = \"name\" value = \"Nuha\" \/>\r\n <property name = \"age\" value = \"2\"\/>\r\n <\/bean>\r\n<\/beans><\/pre>\n
\nInside Profile constructor.<\/strong>
\nAge: 11<\/strong>
\nName: Hari<\/strong>
\nSo, this was all about Spring<\/a> Annotation Tutorial. Hope you like our explanation.<\/p>\n4. Conclusion<\/h2>\n