广州手机网站建设联系电话,微信crm系统软件,网站工程前端,采集站seo赚钱辅导班学习如何编写Spring Setter依赖注入示例 。 Setter注入是Spring依赖注入的一种 。 Spring支持字段注入#xff0c;Setter注入以及构造函数注入#xff0c;以将依赖项注入Spring托管的bean中。 本教程的范围仅限于Setter注入。 有关Spring依赖注入的更多信息#xff1a; Sp… 学习如何编写Spring Setter依赖注入示例 。 Setter注入是Spring依赖注入的一种 。 Spring支持字段注入Setter注入以及构造函数注入以将依赖项注入Spring托管的bean中。 本教程的范围仅限于Setter注入。 有关Spring依赖注入的更多信息 Spring构造函数依赖注入示例 Spring字段依赖注入示例 Spring依赖注入–字段vs设置器vs构造函数注入 Spring依赖注入和控制反转 考虑一下我们有一个DogsService 它是一个基于Spring的REST服务。 我们将编写一个DogsController DogsService和DogsDao 。 这是一个不执行任何操作的虚拟服务。 这里的目的是了解Spring Dependency Injection如何与Setter方法一起使用。 不知道如何编写Spring Boot Rest Service 阅读 Spring Boot Rest Service 想更多地了解Spring Framework 读这个 Spring框架介绍 Spring框架架构 Spring依赖注入和控制反转 Spring靴休息服务 DogsDao.java 没有字段因此没有依赖性。 我们添加了带有打印消息的无参数构造函数。 package com.amitph.spring.dogs.dao;import com.amitph.spring.dogs.repo.Dog;
import org.springframework.stereotype.Component;import java.util.List;Component
public class DogsDao {public DogsDao(){System.out.println(DogsDao no-arg constructor called);}public ListDog getAllDogs() {System.out.println(DogsDao.getAllDogs called);return null;}
}DogsService.java DogsService取决于DogsDao 。 在下面的类中 setter方法用Autowired注释。 为了查看Setter注入的工作方式我们在setter方法中添加了一条print语句。 除了使用setter方法外我们还添加了无参数构造函数和带有相应打印消息的参数化构造函数 。 package com.amitph.spring.dogs.service;import com.amitph.spring.dogs.dao.DogsDao;
import com.amitph.spring.dogs.repo.Dog;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;import java.util.List;Component
public class DogsService {private DogsDao dao;public ListDog getDogs() {System.out.println(DogsService.getDogs called);return dao.getAllDogs();}Autowiredpublic void setDao(DogsDao dao) {System.out.println(DogsService setter called);this.dao dao;}public DogsService(){System.out.println(DogsService no-arg constructor called);}public DogsService(DogsDao dao) {System.out.println(DogsService arg constructor called);this.dao dao;}
}DogsController.java DogsController依赖于DogsService 。 设置器带有Autowired注释并具有打印语句。 除了setter方法外我们还添加了无参数和参数化构造函数以及相应的打印消息。 package com.amitph.spring.dogs.web;import com.amitph.spring.dogs.repo.Dog;
import com.amitph.spring.dogs.service.DogsService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import java.util.List;RestController
RequestMapping(/dogs)
public class DogsController {private DogsService service;GetMappingpublic ListDog getDogs() {return service.getDogs();}Autowiredpublic void setService(DogsService service) {System.out.println(DogsController setter called);this.service service;}
}应用启动 . ____ _ __ _ _/\\ / ____ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | _ | _| | _ \/ _ | \ \ \ \\\/ ___)| |_)| | | | | || (_| | ) ) ) ) |____| .__|_| |_|_| |_\__, | / / / /|_||___//_/_/_/:: Spring Boot :: (v2.1.0.RELEASE)2019-02-04 19:06:17.058 INFO 68545 --- [ main] com.amitph.spring.dogs.Application : Starting Application on Amitsofficemac.gateway with PID 68545 (/Users/aphaltankar/Workspace/personal/dog-service-jpa/out/production/classes started by aphaltankar in /Users/aphaltankar/Workspace/personal/dog-service-jpa)
2019-02-04 19:06:17.061 INFO 68545 --- [ main] com.amitph.spring.dogs.Application : No active profile set, falling back to default profiles: default
2019-02-04 19:06:17.670 INFO 68545 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data repositories in DEFAULT mode.
2019-02-04 19:06:17.724 INFO 68545 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 48ms. Found 1 repository interfaces.
2019-02-04 19:06:17.992 INFO 68545 --- [ main] trationDelegate$BeanPostProcessorChecker : Bean org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration of type [org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration$$EnhancerBySpringCGLIB$$4a5366ed] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2019-02-04 19:06:18.225 INFO 68545 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2019-02-04 19:06:18.237 INFO 68545 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2019-02-04 19:06:18.237 INFO 68545 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/9.0.12
2019-02-04 19:06:18.242 INFO 68545 --- [ main] o.a.catalina.core.AprLifecycleListener : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [/Users/aphaltankar/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.]
2019-02-04 19:06:18.315 INFO 68545 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2019-02-04 19:06:18.315 INFO 68545 --- [ main] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 1205 ms
2019-02-04 19:06:18.339 INFO 68545 --- [ main] o.s.b.w.servlet.ServletRegistrationBean : Servlet dispatcherServlet mapped to [/]
2019-02-04 19:06:18.342 INFO 68545 --- [ main] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: characterEncodingFilter to: [/*]
2019-02-04 19:06:18.342 INFO 68545 --- [ main] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: hiddenHttpMethodFilter to: [/*]
2019-02-04 19:06:18.342 INFO 68545 --- [ main] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: formContentFilter to: [/*]
2019-02-04 19:06:18.342 INFO 68545 --- [ main] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: requestContextFilter to: [/*]
2019-02-04 19:06:18.434 INFO 68545 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
2019-02-04 19:06:18.524 INFO 68545 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed.
2019-02-04 19:06:18.645 INFO 68545 --- [ main] o.hibernate.jpa.internal.util.LogHelper : HHH000204: Processing PersistenceUnitInfo [name: default...]
2019-02-04 19:06:18.690 INFO 68545 --- [ main] org.hibernate.Version : HHH000412: Hibernate Core {5.3.7.Final}
2019-02-04 19:06:18.691 INFO 68545 --- [ main] org.hibernate.cfg.Environment : HHH000206: hibernate.properties not found
2019-02-04 19:06:18.779 INFO 68545 --- [ main] o.hibernate.annotations.common.Version : HCANN000001: Hibernate Commons Annotations {5.0.4.Final}
2019-02-04 19:06:18.868 INFO 68545 --- [ main] org.hibernate.dialect.Dialect : HHH000400: Using dialect: org.hibernate.dialect.MySQL5InnoDBDialect
2019-02-04 19:06:19.279 INFO 68545 --- [ main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit default
DogsDao no-arg constructor called
DogsService no-arg constructor called
DogsService setter called
DogsController no-arg constructor called
DogsController setter called
2019-02-04 19:06:19.650 INFO 68545 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService applicationTaskExecutor
2019-02-04 19:06:19.681 WARN 68545 --- [ main] aWebConfiguration$JpaWebMvcConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning
2019-02-04 19:06:19.856 INFO 68545 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path
2019-02-04 19:06:19.859 INFO 68545 --- [ main] com.amitph.spring.dogs.Application : Started Application in 3.138 seconds (JVM running for 3.647) 春天发生的事情是Spring首先尝试实例化DogsController并发现了对DogsService的依赖。 因此它实例化了DogsService 而后者又依赖于DogsDao 。 因此 DogsDao是第一个实例化的然后是DogsService 最后是DogsController 。 让我们详细看看发生了什么。 第36行调用DogsDao无参数构造函数。 第37行调用DogsService无参数构造函数。 注意参数化的构造函数永远不会被调用 。 第38行调用DogsService Setter。 注入DogsDao实例在第36行创建的位置。 第39行调用DogsController无参数构造函数。 第40行调用DogsController Setter方法。 DogsService实例在第37行中创建。 摘要 您学习了如何在Spring应用程序中编写Setter注入 。 如果使用Setter注入 则使用Autowired注释setter方法。 Spring将首先使用无参数构造函数实例化Bean然后调用setter方法来注入依赖项。 在接下来的教程中我们将了解基于构造函数的注入是如何工作的。 翻译自: https://www.javacodegeeks.com/2019/02/spring-setter-dependency-injection-example.html
