之前我们创建基于Spring的项目需要考虑添加哪些Spring依赖和第三方的依赖。使用Spring Boot后,我们可以以最小化的依赖开始spring应用。大多数Spring Boot应用需要很少的配置即可运行,比如我们可以创建独立独立大Java应用,然后通过java -jar运行启动或者传统的WAR部署。其也提供了命令行工具来直接运行Spring脚本(如groovy脚本)。也就是说Spring Boot让Spring应用从配置到运行变的更加简单,但不对Spring本身提供增强(即额外的功能)。
目的:
让所有Spring开发变得更快,且让更多的人更快的进行Spring入门体验,提供“starter” POM来简化我们的Maven配置(也就是说使用Spring Boot只有配合maven/gradle等这种依赖管理工具才能发挥它的能力),不像以前,构建一个springmvc项目需要进行好多配置等
开箱即用,快速开始需求开发而不被其他方面影响(如果可能会自动配置Spring)
提供一些非功能性的常见的大型项目类特性(如内嵌服务器、安全、度量、健康检查、外部化配置),如可以直接地内嵌Tomcat/Jetty(不需要单独去部署war包)
绝无代码生成,且无需XML配置
一、创建一个普通maven的Jar项目,在pom.xml中引入springboot的依赖包
<dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> <version>1.3.3.RELEASE</version> </dependency> </dependencies>
二、创建Controller类
package com.chen.controller; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.EnableAutoConfiguration; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.ResponseBody; @Controller @EnableAutoConfiguration public class HelloWorldController { @RequestMapping(value="/hello",method=RequestMethod.GET) @ResponseBody public String sayHello(){ return "hello world!"; } public static void main(String[] args) { SpringApplication.run(HelloWorldController.class, args); } }
运行HelloWorldController类,在浏览器上输入http://localhost:8080/hello
即可查看到调用结果 。
常遇问题:
1、引入parent失败
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.3.3.RELEASE</version>
</parent>
配置仓库即可
<repositories> <repository> <id>spring-snapshots</id> <url>http://repo.spring.io/libs-snapshot</url> </repository> </repositories> <pluginRepositories> <pluginRepository> <id>spring-snapshots</id> <url>http://repo.spring.io/libs-snapshot</url> </pluginRepository> </pluginRepositories>
2、
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
继承spring-boot-starter-parent后我们可以继承一些默认的依赖,这样就无需添加一堆相应的依赖,把依赖配置最小化;spring-boot-starter-web提供了对web的支持,spring-boot-maven-plugin提供了直接运行项目的插件,我们可以直接mvn spring-boot:run运行。
二、运行
第一种方式
通过在UserController中加上@EnableAutoConfiguration开启自动配置,然后通过SpringApplication.run(UserController.class);运行这个控制器;这种方式只运行一个控制器比较方便;
第二种方式
通过@Configuration+@ComponentScan开启注解扫描并自动注册相应的注解Bean
package com.chen.controller; import org.springframework.boot.context.properties.EnableConfigurationProperties; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.ResponseBody; @Controller @EnableConfigurationProperties public class WelcomeController { @RequestMapping(value="/welcome",method=RequestMethod.GET) @ResponseBody public String welcome(){ return "welcome"; } } package com.chen.app; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.EnableAutoConfiguration; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.Configuration; @Configuration @ComponentScan(basePackages="com") @EnableAutoConfiguration public class Application { public static void main(String[] args) { SpringApplication.run(Application.class, args); } }运行Application类即可发布整个应用
三、springboot应用添加hibernate持久层框架
1、引入依赖包
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>4.3.7.Final</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.34</version>
</dependency>
2、添加application.properties配置文件
spring.datasource.url=jdbc:mysql://localhost:3306/test spring.datasource.username=root spring.datasource.password=root spring.datasource.driverClassName=com.mysql.jdbc.Driver spring.jpa.database = MYSQL spring.jpa.hibernate.ddl-auto=update spring.jpa.show-sql = true spring.jpa.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect
3、写POJO
package com.chen.pojo; import java.util.Date; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Table; @Entity @Table(name="t_user") public class User { private Long id ; private String username; private Date birthday; private String sex ; private String address; @Id @GeneratedValue(strategy=GenerationType.AUTO) @Column(name="id") public Long getId() { return id; } public void setId(Long id) { this.id = id; } @Column(name="username") public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } @Column(name="birthday") public Date getBirthday() { return birthday; } public void setBirthday(Date birthday) { this.birthday = birthday; } @Column(name="sex") public String getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } @Column(name="adress") public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } @Override public String toString() { return "User [id=" + id + ", username=" + username + ", birthday=" + birthday + ", sex=" + sex + ", address=" + address + "]"; } }
4、写repository
package com.chen.repository; import javax.persistence.Table; import org.springframework.beans.factory.annotation.Qualifier; import org.springframework.data.jpa.repository.Query; import org.springframework.data.repository.CrudRepository; import org.springframework.data.repository.query.Param; import org.springframework.stereotype.Repository; import com.chen.pojo.User; @Repository @Table(name="t_user") @Qualifier("userRepository") public interface UserRepository extends CrudRepository<User,Long>{ public User findOne(Long id); @Query("select t from User t where t.username=:name") public User findUserByName(@Param("name") String name); }
5、在启动类添加注解
package com.chen.app; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.EnableAutoConfiguration; import org.springframework.boot.orm.jpa.EntityScan; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.Configuration; import org.springframework.data.jpa.repository.config.EnableJpaRepositories; @Configuration @ComponentScan(basePackages="com.chen") @EnableAutoConfiguration @EntityScan(basePackages="com.chen.pojo") @EnableJpaRepositories(basePackages="com.chen.repository") public class Application { public static void main(String[] args) { SpringApplication.run(Application.class, args); } }
6、添加控制器类
package com.chen.controller; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.autoconfigure.EnableAutoConfiguration; import org.springframework.data.repository.query.Param; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.ResponseBody; import com.chen.pojo.User; import com.chen.repository.UserRepository; @Controller @EnableAutoConfiguration public class UserController { @Autowired private UserRepository userRepository; @RequestMapping(value="/user/getUserById") @ResponseBody public User getUserById(@RequestParam Long id){ System.out.println("hello user"); User u = userRepository.findOne(id); System.out.println(userRepository); System.out.println(u); return u; } @RequestMapping(value="/user/findUserByName") @ResponseBody public User findUserByName(@RequestParam String name){ System.out.println("hello user"); User u = userRepository.findUserByName(name); System.out.println(u); return u; } }
源码见附件