创建配置类Config代替Spring的xml配置文件

整体结构：

1.建立一个DTO

public class User {
   private String username;
   private String password;
   private Integer age;
public String getUsername() {
	return username;
}
public void setUsername(String username) {
	this.username = username;
}
public String getPassword() {
	return password;
}
public void setPassword(String password) {
	this.password = password;
}
public Integer getAge() {
	return age;
}
public void setAge(Integer age) {
	this.age = age;
}
}

2.建立Dao类，这里模拟数据查询，没有连接数据库（没有使用注解）

package com.spring.javaconfig;

import java.util.ArrayList;
import java.util.List;

public class UserDao {
	
     public List<User> querryUserList(){
    	 List<User> result=new ArrayList<User>();
    	 for(int i=0;i<10;i++){
    		 User user=new User();
    		 user.setUsername("username"+i);
    		 user.setPassword("password"+i);
    		 user.setAge(i+1);
    		 result.add(user);
    	 }
    	 return result;
     }
}

3.建立service，使用注解

@Service
public class UserService {
    @Autowired
	private UserDao userdao;
    
    public List<User> querryUserList(){
    	return userdao.querryUserList();
    }
}

4.建立配置文件类 SpringConfig

package com.spring.javaconfig;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;

import com.jolbox.bonecp.BoneCPDataSource;

/*
 * @Configuration 该注解表明该类相当于spring的xml配置文件
 * @PropertySource 注解 ignoreResourceNotFound=true 查找不到配置文件就自动忽略
  * 加载多个配置文件value={"classpath:jdbc1.properties","classpath:jdbc2.properties"}
 */
@Configuration
@ComponentScan(basePackages="com.spring.javaconfig")   //包扫描
@PropertySource(value={"classpath:jdbc.properties"},ignoreResourceNotFound=true) //加载配置文件
public class SpringConfig {

	  @Bean //ͨ相当于spring中的<bean>
	  public UserDao getUserDao(){
		  return new UserDao();
	  }
	  
	  //加载配置jdbc配置文件
	  @Value("${jdbc.driverClassName}")
	  private String driverClassName;
	  @Value("${jdbc.url}")
	  private String url;
	  @Value("${jdbc.username}")
	  private String username;
	  @Value("${jdbc.password}")
	  private String password;
	  
	  
	  @Bean(destroyMethod="close") //关闭连接，将连接放回连接池
	  public BoneCPDataSource boneCPDataSource(){
		  BoneCPDataSource boneCPDataSource=  new BoneCPDataSource();
		  boneCPDataSource.setDriverClass(driverClassName);
		  boneCPDataSource.setJdbcUrl(url);
		  boneCPDataSource.setUsername(username);
		  boneCPDataSource.setPassword(password);
		  boneCPDataSource.setIdleMaxAgeInMinutes(30);
		  boneCPDataSource.setMaxConnectionsPerPartition(100);
		  boneCPDataSource.setMinConnectionsPerPartition(5);
		  return boneCPDataSource;
	  }
}

5.建立主方法类，AnnotationConfigApplicationContext类来加载配置文件，启动Spring.

package com.spring.javaconfig;

import java.util.List;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class Main {
    public static void main(String[] args) {
	   //ͨ容器加载Spring配置文件
    	AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext(SpringConfig.class);
	   //获取指定的bean
    	UserService service=context.getBean(UserService.class);
    	//通过注解了的service来调用我们没有注解的Dao
    	List<User> list=service.querryUserList();
	    for(User user:list){
	    	System.out.println(user.getUsername()+":"+user.getPassword()+":"+user.getAge());
	    }
    	//关闭容器
	    context.destroy();
	}	
}

这里只使用了spring

<!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-core</artifactId>
			<version>4.3.14.RELEASE</version>
		</dependency>
		
<!-- https://mvnrepository.com/artifact/org.springframework/spring-web -->
	  <dependency>
	    <groupId>org.springframework</groupId>
	    <artifactId>spring-web</artifactId>
	    <version>4.3.14.RELEASE</version>
	  </dependency>