SpringBoot中Controller以及Jpa操作数据库的使用

常用注解

1. @PathVariable：获取Url中的数据
2. @RequestParam： 获取请求参数的值
3. @GetMapping ： 组合注解，相当于@RequestMapping(method = RequestMethod.GET)
4. @PostMapping： 组合注解，相当于@RequestMapping(method = RequestMethod.POST)

5. @RestController：组合注解，相当于@Controller 加 @ResponseBody

   

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## Jpa ##

• Spring-Data-Jpa定义了一系列对象持久化的标准，目前实现这一规范的产品有Hibernate,TopLink.

  pom依赖：

<parent>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-starter-parent</artifactId>        <version>1.5.2.RELEASE</version>        <relativePath/> <!-- lookup parent from repository -->    </parent>    <properties>        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>        <java.version>1.8</java.version>    </properties>    <dependencies>        <!--web项目必须引入的依赖-->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>        </dependency>        <!--单元测试-->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-test</artifactId>            <scope>test</scope>        </dependency>        <!--Jpa-->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-data-jpa</artifactId>        </dependency>        <!--mysql附件-->        <dependency>            <groupId>mysql</groupId>            <artifactId>mysql-connector-java</artifactId>        </dependency>        <!--spring官方模板，跳转指定页面-->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-thymeleaf</artifactId>        </dependency>    </dependencies>    <build>        <plugins>            <plugin>                <groupId>org.springframework.boot</groupId>                <artifactId>spring-boot-maven-plugin</artifactId>            </plugin>        </plugins>    </build>

数据库配置：

增删改查代码：
实体类 ：

package com.cym;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;/** * Created by hasee * on 2017/4/15. */@Entity    //表示当前类代表数据库中的表public class Girl {    @Id    @GeneratedValue   //自增    private Integer id;    private Integer age;    public Girl() {    }    public Integer getId() {        return id;    }    public void setId(Integer id) {        this.id = id;    }    public Integer getAge() {        return age;    }    public void setAge(Integer age) {        this.age = age;    }}

接口：

package com.cym;import org.springframework.data.jpa.repository.JpaRepository;import java.util.List;/** * Created by hasee * on 2017/4/15. */public interface GirlPreposity extends JpaRepository<Girl,Integer>{    //通过年龄age查询   public List<Girl> findByAge(Integer age);}

Controller层（逻辑实际是写在servicec层，这里为了简化）：

/** * Created by hasee * on 2017/4/15. */@RestControllerpublic class GirlController {    @Autowired    private GirlPreposity girlPreposity;    /**     *查询所有列表     */    @GetMapping(value = "/girls")    public List<Girl> findlist(){        return girlPreposity.findAll();    }    /**     *id查询一条数据     */    @GetMapping(value = "/select")    public Girl findid(@RequestParam(value = "id",defaultValue = "1") Integer id){        return girlPreposity.findOne(id);    }    /**     *age 查询     */    @GetMapping(value = "/girls/age/{age}")    public List<Girl> findlist1(@PathVariable("age") Integer age){        return girlPreposity.findByAge(age);    }    /**     *添加一条数据     */    @PostMapping (value= "/girls")    public Girl add(@RequestParam(value = "age") Integer age){        Girl girl = new Girl();        girl.setAge(age);        return girlPreposity.save(girl);    }    /**     *更新     */    @PutMapping(value= "/girls/{id}")    public Girl update(@PathVariable("id") Integer id,                       @RequestParam(value = "age") Integer age){        Girl girl = new Girl();        girl.setId(id);        girl.setAge(age);        System.out.println(id+age);        return girlPreposity.save(girl);    }    /**     *更新     */    @DeleteMapping(value= "/girls/{id}")    public void delet(@PathVariable("id") Integer id){        girlPreposity.delete(id);    }}