spring boot入门

（1）需要使用maven来构建项目，加载起来很简单，直接在POM.xml文件引入依赖即可！运行起来也像普通的Java程序一样，一个应用占用Tomcat容器的一个端口，像普通程序一样停止Java程序就把相应的端口释放掉了。

因为像普通程序，所以只有一个main方法，而且必须要有一个main，应该是作为程序的入口，加载一些上下文，容器之类的吧

因为不同项目不同的tomcat端口，所以url不用加项目名称

<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>ywsg</groupId>  <artifactId>springbootdemo</artifactId>  <packaging>war</packaging>  <version>0.0.1-SNAPSHOT</version>  <name>springbootdemo Maven Webapp</name>  <url>http://maven.apache.org</url>      <parent>    <groupId>org.springframework.boot</groupId>    <artifactId>spring-boot-starter-parent</artifactId>    <version>1.2.5.RELEASE</version>    <relativePath/>  </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></dependency>  </dependencies>      <build>    <finalName>springbootdemo</finalName>    <plugins>      <plugin>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-maven-plugin</artifactId>      </plugin>    </plugins>  </build></project>

（2）Spring boot加载简单，用起来也简单，如结和JPA实现CRUD和事务管理

package hello;import java.util.List;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestParam;import org.springframework.web.bind.annotation.RestController;@RestControllerpublic class StudentController {@Autowiredprivate StuRepository stuRepository;@RequestMapping("/stus")public List<Student> stuList() {return stuRepository.findAll();}@RequestMapping("/add")public Student add(@RequestParam("age") String age) {Student stu = new Student();stu.setAge(age);return stuRepository.save(stu);}@RequestMapping("/getById")public Student get(@RequestParam("id") Integer id) {return stuRepository.findOne(id);}@RequestMapping("/update")public Student update(@RequestParam("id") Integer id, @RequestParam("age") String age) {Student stu = new Student();stu.setAge(age);stu.setId(id);System.out.println("update...");// 跟新也用savereturn stuRepository.save(stu);}@RequestMapping("/remove")public void remove(@RequestParam("id") Integer id) {stuRepository.delete(id);}@RequestMapping("/getByAge")public List<Student> remove(@RequestParam("age") String age) {return stuRepository.findByAge(age);}// 事务管理@Autowiredprivate StudentService studentService;@RequestMapping("/addTwo")public void addTwo() {studentService.addTwo();}}

package hello;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import org.springframework.transaction.annotation.Transactional;@Servicepublic class StudentService {@Autowiredprivate StuRepository stuRepository;@Transactionalpublic void addTwo() {Student stu1 = new Student();stu1.setAge("1");stuRepository.save(stu1);Student stu2 = new Student();stu2.setAge("5678");stuRepository.save(stu2);}}

package hello;import java.util.List;import org.springframework.data.jpa.repository.JpaRepository;public interface StuRepository extends JpaRepository<Student, Integer>{// 通过年龄来查询// 只要写个方法就好了，都不要实现了，但是方法名有规范public List<Student> findByAge(String age);}

注意：StuRepository extends JpaRepository<Student, Integer>的使用

（3）在application.properties文件配置必要的信息：

server.port=8000spring.datasource.url=jdbc:mysql://localhost/testspring.datasource.username=rootspring.datasource.password=1spring.datasource.driver-class-name=com.mysql.jdbc.Driverspring.jpa.hibernate.ddl-auto=updatespring.jpa.show-sql:true

总体来说，用springboot确实简化了不少