pom.xml
<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.bbsdj</groupId> <artifactId>springboot01</artifactId> <packaging>war</packaging> <version>1.0-SNAPSHOT</version> <name>springboot01 Maven Webapp</name> <url>http://maven.apache.org</url> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.6.RELEASE</version> </parent> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>3.8.1</version> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.34</version> </dependency> </dependencies> <build> <finalName>springboot01</finalName> </build> </project>
application.properties,springboot会自动加载
spring.datasource.username=root spring.datasource.password=root spring.datasource.url=jdbc:mysql:///demo?useUnicode=true&characterEncoding=UTF-8 spring.datasource.driver-class-name=com.mysql.jdbc.Driver spring.jpa.database-platform=org.hibernate.dialect.MySQLDialect spring.jpa.show-sql=true spring.jpa.hibernate.ddl-auto=update
实体类 Employee，springboot启动后会自动创建数据库表
package com.bbsdj.entity;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
@Entity
public class Employee {
private Integer id;
private String name;
private Integer age;
@Id
@GeneratedValue
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}dao层
package com.bbsdj.dao;
import com.bbsdj.entity.Employee;
import org.springframework.data.repository.Repository;
public interface EmployeeDao extends Repository<Employee,Integer> {
/**
* 根据id查找雇员
* @param id 输入的id
* @return
*/
public Employee findById(Integer id);
}最后SpringBoot启动类
package com.bbsdj.web;
import com.bbsdj.dao.EmployeeDao;
import com.bbsdj.entity.Employee;
import com.bbsdj.service.EmployeeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
@Controller
@EnableAutoConfiguration
@EnableJpaRepositories(basePackages = "com.bbsdj.dao")
@EntityScan(basePackages = "com.bbsdj.entity")
@ComponentScan("com.bbsdj")
public class App {
@Autowired
private EmployeeDao employeeDao;
@RequestMapping("/getName/{id}")
@ResponseBody
public String getName( @PathVariable("id") Integer id){
Employee employee = employeeDao.findById(id);
if(employee == null){
return "没有查到数据.";
}
return employee.getName();
}
public static void main(String[] args){
SpringApplication.run(App.class,args);
}
}如果service、dao都在同一个包下面，就不需要EnableJpaRepositories、EntityScan、ComponentScan注解，如果没有在同一个包下面就需要加上这几个注解，因为springboot只会扫描当前以及子包下面的类，如果同级的类默认是不会扫描的。
另外一种解决方案就是把app启动类放到父包下面，如:com.demo.web、com.demo.dao、com.demo.service，就可以把app启动类放到com.demo下面。这样就解决了包扫描不到的情况。
