3, Spring EL and the Bean Scope

1, Bean's Scope
　　Scope describes how to create a Spring container is Bean instance, achieved by @Scope ( "xxxx") notes
　　singleton: Bean is only one example of a container Spring, Spring is the default configuration, all sharing a container instance
　　　　default to comment @Service Bean and other defaults are single cases, if it is a multi-server deployment, load balancing exist, the same Bean exist in each server.
　　prototype: Each call Bean to create a new instance of
　　　　the prototype model, injection or other Bean acquired by getBean, will create an instance of
　　request: to every http request to create a new Bean instance
　　session: each http session to create a new Bean instance
2, Spring EL and resources to call
　　expression language
　　use can be achieved EL inject resources, resources that is simple to understand initialization

 1 import org.apache.commons.io.IOUtils;
 2 import org.springframework.beans.factory.annotation.Autowired;
 3 import org.springframework.beans.factory.annotation.Value;
 4 import org.springframework.context.annotation.Bean;
 5 import org.springframework.context.annotation.ComponentScan;
 6 import org.springframework.context.annotation.Configuration;
 7 import org.springframework.context.annotation.PropertySource;
 8 import org.springframework.context.support.PropertySourcesPlaceholderConfigurer;
 9 import org.springframework.core.env.Environment;
10 import org.springframework.core.io.Resource;
11 
12 @Configuration
13 @ComponentScan("com.ning.ch2.el.*")
14 @PropertySource("classpath:com/ning/ch2/el/el.properties")
15 public class ElConfig {
16     //注入普通字符
17     @Value("this is spring boot")
18     private String normal;
19     
20     //注入操作系统属性
21     @Value("#{systemProperties['os.name']}")
22     privateOSNAME String;
 23 is      
24      // injection operation result of the expression 
25      @Value ( "# {T (java.lang.Math) .random ()} 100.0 *" )
 26 is      Private  Double randomNumber;
 27      
28      // injection properties of other Bean
 29      // class name for an lowercase funService beginning private property name getter methods needed 
30      @Value ( "funService.name # {}" )
 31 is      private String fromFunServiceName;
 32      
33 is      // injection profile
 34      // has been designated file location , or does not require complex configuration PropertySourcesPlaceholderConfigurer @PropertySource annotation of Bean 
35      @Value ( "CLASSPATH: COM / Ning / CH2 / EL / el.properties" )
36      Private the Resource testFile;
 37 [      
38 is      // injection URL content 
39      @Value ( "https://www.baidu.com/" )
 40      Private the Resource testUrl;
 41 is      
42 is      // @Value ( " HTTPS: //www.cnblogs. COM / shipengzhi / Articles / 2099693.html ")
 43 is      // Private the Resource bolgUrl;
 44 is      
45      // injection attribute file
 46      // need @PropertySource location of the file and the configuration PropertySourcesPlaceholderConfigurer Bean 
47      @Value ("} $ {book.name " )
 48      Private String bookName;
 49      
50      //注入的配置文件可以从Environment获取
51     @Autowired
52     private Environment environment;
53     
54     @Bean
55     public static PropertySourcesPlaceholderConfigurer propertyConfigure() {
56         return new PropertySourcesPlaceholderConfigurer();
57     }
58     
59     public void outputResource() {
60         System.out.println("start...");
61         System.out.println(normal);
62         System.out.println(osName);
63         System.out.println(randomNumber);
64         System.out.println(fromFunServiceName);
65         try {
66             System.out.println(IOUtils.toString(testFile.getInputStream()));
67             System.out.println(IOUtils.toString(testUrl.getInputStream()));
68             //System.out.println(IOUtils.toString(bolgUrl.getInputStream()));
69         } catch (IOException e) {
70             e.printStackTrace();
71         }
72         
73         System.out.println(bookName);
74         //需要@PropertySource指定配置文件位置
75         System.out.println(environment.getProperty("book.anthor"));
76         System.out.println("end...");
77     }
78 }