springboot的Jpa框架介绍
目录
- 前言
-
- Jpa能做到的
-
- Jpa的配置文件pom.xml,yml
- 1、通过操控java实体类而自动生成数据库表结构
- 2、jpa继承JpaRepository后就有一套简单的增删改查
- 用jpa+bootstarp做一个增删改查和文件上传
-
- 重点文件配置
-
- pom.xml
- application.yml
- 重点文件介绍
-
- 一个文件上传的配置类MyWebAppConfigurer
- 在控制层控制好图片的存放位置
- 项目结构和结果图
- 后记
前言
JPA是Java Persistence API的简称:中文名Java持久层API
是JDK 5.0注解或XML描述对象－关系表的映射关系，并将运行期的实体对象持久化到数据库中。
简单的说hibernate就是他的底层。所有的都可以参照hibernate
Jpa能做到的
Jpa的配置文件pom.xml,yml
pom.xml
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-data-jpaartifactId>
dependency>
application.yml
jpa:
hibernate:
ddl-auto: update
show-sql: true
1、通过操控java实体类而自动生成数据库表结构
比如说写了这个实体类，不用在数据库建表，在运行过程中他就会自动创建好。
package com.liwangwang.springboot3.entity;
import lombok.ToString;
import javax.persistence.*;
@data
@Entity
@Table(name = "t_springboot_teacher")
@ToString
public class Teacher {
@Id
@GeneratedValue
private Integer tid;
@Column(length = 16)
private String tname;
@Column(length = 4)
private String sex;
@Column(length = 100)
private String description;
@Column(length = 200)
private String imagePath;
}
创建之前
创建之后
2、jpa继承JpaRepository后就有一套简单的增删改查
package com.liwangwang.springboot3.dao;
import com.liwangwang.springboot3.entity.Teacher;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
/**
* 只要继承JpaRepository，通常所用的增删查改方法都有
* 第一个参数：操作的实体类
* 第二个参数：实体类对应数据表的主键
*
* 要使用高级查询必须继承
* org.springframework.data.jpa.repository.JpaSpecificationExecutor接口
*/
public interface TeacherDao extends JpaRepository<Teacher, Integer>, JpaSpecificationExecutor<Teacher> {
}
用jpa+bootstarp做一个增删改查和文件上传
重点文件配置
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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0modelVersion>
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>2.2.1.RELEASEversion>
<relativePath/>
parent>
<groupId>com.liwangwanggroupId>
<artifactId>springboot3artifactId>
<version>0.0.1-SNAPSHOTversion>
<name>springboot3name>
<description>Demo project for Spring Bootdescription>
<properties>
<java.version>1.8java.version>
<mysql.version>5.1.44mysql.version>
properties>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-data-jdbcartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-thymeleafartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
<version>${mysql.version}version>
<scope>runtimescope>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<optional>trueoptional>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
<exclusions>
<exclusion>
<groupId>org.junit.vintagegroupId>
<artifactId>junit-vintage-engineartifactId>
exclusion>
exclusions>
dependency>
<dependency>
<groupId>com.alibabagroupId>
<artifactId>druid-spring-boot-starterartifactId>
<version>1.1.10version>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-aspectsartifactId>
dependency>
<dependency>
<groupId>com.github.pagehelpergroupId>
<artifactId>pagehelper-spring-boot-starterartifactId>
<version>1.2.3version>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-data-redisartifactId>
dependency>
<dependency>
<groupId>redis.clientsgroupId>
<artifactId>jedisartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-data-jpaartifactId>
dependency>
<dependency>
<groupId>commons-fileuploadgroupId>
<artifactId>commons-fileuploadartifactId>
<version>1.3.1version>
dependency>
dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-maven-pluginartifactId>
plugin>
plugins>
build>
project>
application.yml
server:
servlet:
context-path: /
port: 80
spring:
jpa:
hibernate:
ddl-auto: update
show-sql: true
datasource:
type: com.alibaba.druid.pool.DruidDataSource
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/context?useUnicode=true&characterEncoding=utf8
username: root
password: 123
druid:
initial-size: 5
min-idle: 5
max-active: 20
max-wait: 60000
time-between-eviction-runs-millis: 60000
min-evictable-idle-time-millis: 30000
validation-query: SELECT 1 FROM DUAL
test-while-idle: true
test-on-borrow: true
test-on-return: false
pool-prepared-statements: true
max-pool-prepared-statement-per-connection-size: 20
filter:
stat:
merge-sql: true
slow-sql-millis: 5000
web-stat-filter:
enabled: true
url-pattern: /*
exclusions: "*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*"
session-stat-enable: true
session-stat-max-count: 100
stat-view-servlet:
enabled: true
url-pattern: /druid/*
reset-enable: true
login-username: admin
login-password: admin
allow: 127.0.0.1
thymeleaf:
cache: false
# 解决图片上传大小限制问题，也可采取配置类
servlet:
multipart:
max-file-size: 20MB
max-request-size: 60MB
重点文件介绍
一个文件上传的配置类MyWebAppConfigurer
没有这个配置类就没办法上传图片了
package com.liwangwang.springboot3.config;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
/**
* 资源映射路径
*/
@Configuration
public class MyWebAppConfigurer extends WebMvcConfigurationSupport {
@Override
protected void addResourceHandlers(ResourceHandlerRegistry registry) {
registry.addResourceHandler("/static/**").addResourceLocations("classpath:/static/");
registry.addResourceHandler("/uploadImages/**").addResourceLocations("file:E:/temp/");
super.addResourceHandlers(registry);
}
}
在控制层控制好图片的存放位置
package com.liwangwang.springboot3.controller;
import com.liwangwang.springboot3.entity.Teacher;
import com.liwangwang.springboot3.service.TeacherService;
import com.liwangwang.springboot3.util.PageBean;
import com.liwangwang.springboot3.util.PageUtil;
import com.liwangwang.springboot3.util.StringUtils;
import org.apache.commons.io.FileUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.io.IOException;
@Controller
@RequestMapping("/teacher")
public class TeacherController {
@Autowired
private TeacherService teacherService;
@RequestMapping("/listPager")
public ModelAndView list(Teacher teacher, HttpServletRequest request){
PageBean pageBean = new PageBean();
pageBean.setRequest(request);
ModelAndView modelAndView = new ModelAndView();
Page<Teacher> teachers = teacherService.listPager(teacher, pageBean);
modelAndView.addObject("teachers",teachers.getContent());
pageBean.setTotal(teachers.getTotalElements()+"");
modelAndView.addObject("pageCode", PageUtil.createPageCode(pageBean)/*.replaceAll("<","<").replaceAll(">:",">")*/);
modelAndView.setViewName("list");
return modelAndView;
}
@RequestMapping("/toEdit")
public ModelAndView toEdit(Teacher teacher){
ModelAndView modelAndView = new ModelAndView();
modelAndView.setViewName("edit");
modelAndView.addObject("sexArr",new String[]{"男","女"});
if(!(teacher.getTid() == null || "".equals(teacher.getTid()))) {
Teacher t = teacherService.findById(teacher.getTid());
modelAndView.addObject("teacher", t);
}
return modelAndView;
}
@RequestMapping("/add")
public String add(Teacher teacher, MultipartFile image){
try {
String diskPath = "E://temp/"+image.getOriginalFilename();
String serverPath = "/uploadImages/"+image.getOriginalFilename();
if(StringUtils.isNotBlank(image.getOriginalFilename())){
FileUtils.copyInputStreamToFile(image.getInputStream(),new File(diskPath));
teacher.setImagePath(serverPath);
}
teacherService.save(teacher);
} catch (IOException e) {
e.printStackTrace();
}
return "redirect:/teacher/listPager";
}
@RequestMapping("/edit")
public String edit(Teacher teacher, MultipartFile image){
String diskPath = "E://temp/"+image.getOriginalFilename();
String serverPath = "/uploadImages/"+image.getOriginalFilename();
if(StringUtils.isNotBlank(image.getOriginalFilename())){
try {
FileUtils.copyInputStreamToFile(image.getInputStream(),new File(diskPath));
teacher.setImagePath(serverPath);
} catch (IOException e) {
e.printStackTrace();
}
}
teacherService.save(teacher);
return "redirect:/teacher/listPager";
}
@RequestMapping("/del/{bid}")
public String del(@PathVariable(value = "bid") Integer bid){
teacherService.deleteById(bid);
return "redirect:/teacher/listPager";
}
}
项目结构和结果图
后记
因为一个jpa文档太多了，所以干脆给项目吧
暂时就放一些重要的代码看看
链接：添加链接描述
提取码：3oy3