Spring教程 - Spring JavaConfig

Spring教程 - Spring JavaConfig

以下部分显示如何使用注释来标记依赖关系为春天

Spring教程 - Spring JavaConfig...

要使用JavaConfig(@Configuration)，您需要包括CGLIB库。

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.www.w3cschool.cnmon</groupId>
  <artifactId>Java2sExamples</artifactId>
  <packaging>jar</packaging>
  <version>1.0-SNAPSHOT</version>
  <name>Java2sExamples</name>
  <url>http://maven.apache.org</url>
  <properties>
    <spring.version>3.0.5.RELEASE</spring.version>
  </properties>  
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
<!-- Spring 3 dependencies -->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>${spring.version}</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>${spring.version}</version>
  </dependency>
  <!-- JavaConfig need this library -->
  <dependency>
    <groupId>cglib</groupId>
    <artifactId>cglib</artifactId>
    <version>2.2.2</version>
  </dependency>
  </dependencies>
</project>

Java Bean

创建一个简单的bean如下。

package com.www.w3cschool.cnmon;

public interface HelloWorld {

  void printHelloWorld(String msg);

}

提供接口的实现。

package com.www.w3cschool.cnmon;

public class HelloWorldImpl implements HelloWorld {

  public void printHelloWorld(String msg) {

    System.out.println("Hello : " + msg);
  }

}

下面的代码显示了如何使用@Configuration告诉Spring这是核心Spring配置文件，并通过@Bean定义bean。

package com.www.w3cschool.cnmon;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class AppConfig {

    @Bean(name="helloBean")
    public HelloWorld helloWorld() {
        return new HelloWorldImpl();
    }
}

主要方法

为了加载我们的JavaConfig类使用AnnotationConfigApplicationContext。

package com.www.w3cschool.cnmon;

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class App {
  public static void main(String[] args) {

            ApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);
      HelloWorld obj = (HelloWorld) context.getBean("helloBean");

      obj.printHelloWorld("Spring3 Java Config");

  }
}

使用以下命令运行上面的代码。

mvn exec:java -Dexec.mainClass="com.www.w3cschool.cnmon.App"  

输出

Spring 3 JavaConfig @Import示例

两个简单的Spring bean。

文件:Customer.java

package com.www.w3cschool.cnmon;

public class Customer {

  public void printMsg(String msg) {

    System.out.println("Customer : " + msg);
  }

}

文件:Employee.java

package com.www.w3cschool.cnmon;
public class Employee {
  public void printMsg(String msg) {
    System.out.println("Employee : " + msg);
  }
}

现在，使用JavaConfig @Configuration来声明上面的bean。

文件:CustomerConfig.java

package com.www.w3cschool.cnmon;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class CustomerConfig {
  @Bean(name="customer")
  public Customer customer(){
       return new Customer();
  }
}

文件:EmployeeConfig.java

package com.www.w3cschool.cnmon;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class EmployeeConfig {
  @Bean(name="employee")
  public Employee employee(){
       return new Employee();
  }
}

使用@Import加载多个配置文件。

文件:AppConfig.java

package com.www.w3cschool.cnmon;
org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
@Configuration
@Import({ CustomerConfig.class, EmployeeConfig.class })
public class AppConfig {
}

加载主配置文件，并进行测试。

package com.www.w3cschool.cnmon;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import com.java2s.config.AppConfig;
public class App {
  public static void main(String[] args) {
    ApplicationContext context = new AnnotationConfigApplicationContext(
        AppConfig.class);
    Customer customer = (Customer) context.getBean("customer");
    customer.printMsg("Hello 1");
    Employee employee = (Employee) context.getBean("employee");
    employee.printMsg("Hello 2");
  }
}

加载主配置文件，并进行测试。...