How to configure spring using JavaConfig

This article mainly introduces how to configure spring using JavaConfig, which has a certain reference value, and interested friends can refer to it. I hope you can learn a lot after reading this article.

JavaConfig was incorporated into Spring from a separate project since Spring 3. 0. JavaConfig can be thought of as a Spring configuration file used to complete the Bean assembly, that is, the Spring container, except that the container is not a XML file, but a Java class written by the programmer himself using Java.

Entity class:

Package com.lzl.spring.entity; public class Car {private String brand;// brand private String type;// model private double speed;// maximum speed public Car () {} public Car (String brand, String type, double speed) {this.brand = brand; this.type = type; this.speed = speed } public String getBrand () {return brand;} public void setBrand (String brand) {this.brand = brand;} public String getType () {return type;} public void setType (String type) {this.type = type } public double getSpeed () {return speed;} public void setSpeed (double speed) {this.speed = speed;} @ Override public String toString () {return "Car [brand=" + brand + ", type=" + type + ", speed=" + speed + "]";}} package com.lzl.spring.entity Public class Person {private Integer id; private String name; private Car car; public Person (Integer id, String name) {this.id = id; this.name = name;} public Person () {} public Person (Integer id, String name, Car car) {this.id = id This.name = name; this.car = car;} public Integer getId () {return id;} public void setId (Integer id) {this.id = id;} public String getName () {return name } public void setName (String name) {this.name = name;} public Car getCar () {return car;} public void setCar (Car car) {this.car = car @ Override public String toString () {return "Person [id=" + id + ", name=" + name + ", car=" + car + "]";}}

Defining a JavaConfig class for a POJO class, using the @ Configuration annotation on the class will make the current class use as a container for Spring to complete the creation of the Bean. Using @ Bean on the method of this JavaConfig will change the result returned by a normal method to an instance of Bean with the specified name.

Package com.lzl.spring.entity; import org.springframework.beans.factory.annotation.Autowire;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration / / this annotation indicates that this class is a java configuration class @ Configurationpublic class MyConfig {/ / this annotation says: register an object called myCar with the container @ Bean ("myCar") public Car getCar () {return new Car ("Porsche", "911,300") } / / this note says: register an object called person in the container / / and inject car @ Bean (name= "person", autowire=Autowire.BY_TYPE) public Person getPerson () {return new Person (1001) into the container by byType;}}

Xml files only need to add automatic scan package configuration

Test class

Package com.lzl.spring.test; import org.junit.Test;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext; import com.lzl.spring.entity.Car;import com.lzl.spring.entity.Person; public class SpringTest {@ Test public void test1 () {/ / read configuration file ApplicationContext ctx=new ClassPathXmlApplicationContext ("spring-config.xml"); Car car = ctx.getBean ("myCar", Car.class) System.out.println (car); Person person = ctx.getBean ("person", Person.class); System.out.println (person);}}

Console output

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