springboot对JPA的支持

Posted 2020-11-23 星海

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springboot之jpa支持

导入相关pom依赖

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

application.yml文件配置

spring:
  jpa:
    hibernate:
      ddl-auto: update
    show-sql: true

自动建表相关代码

@Entity
@Table(name = "t_springboot_book")
public class Book {
    @Id
    @GeneratedValue
    private Integer bid;
    @Column(length = 100)
    private String bname;
    @Column
    private Float price;

数据库自动建表截图

会创建一个序列以及t_springboot_book表

jpa值增删改查

 * 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
 */
public interface JpaDao extends JpaRepository<Book, Integer> {
}

controller层

package com.huang.springboot05.controller;

import com.huang.springboot05.entity.Book;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

/**
 * @auther 宇晨
 * @company
 * @create 2019-11-30-17:15
 */
@RestController
@RequestMapping("/book")
public class BookController {
    @Autowired
    private JpaRepository jpaDao;

    @RequestMapping("/add")
    public String add(Book book){
        jpaDao.save(book);
        return "success";
    }

    @RequestMapping("/edit")
    public String edit(Book book){
        jpaDao.save(book);
        return "success";
    }

    @RequestMapping("/del")
    public String del(Book book){
        jpaDao.delete(book);
        return "success";
    }

    @RequestMapping("/getOne")
    public Book getOne(Integer bid){
//        会出现懒加载问题：org.hibernate.LazyInitializationException: could not initialize proxy - no Session
//        return jpaDao.getOne(bid);
        return (Book)jpaDao.findById(bid).get();
    }

    @RequestMapping("/getAll")
    public List<Book> getAll(){
        return jpaDao.findAll();
    }
}

浏览器输入请求进行测试

http://localhost:8080/springboot/jpa/getOne?bid=11

http://localhost:8080/springboot/jpa/getAll

http://localhost:8080/springboot/jpa/add?bname=xxx&price=234

http://localhost:8080/springboot/jpa/add?bname=xxx&price=234&bid=11

http://localhost:8080/springboot/jpa/del?bid=11

jpa值复杂查询

dao层

 *  使用高级查询必须继承
 * org.springframework.data.jpa.repository.JpaSpecificationExecutor<T>接口
 */
public interface JpaDao extends JpaRepository<Book, Integer>, JpaSpecificationExecutor<Book> {
}

controller层

@RequestMapping("/getCondition")
    public  List<Book> getCondition(Book book){
        return jpaDao.findAll(new Specification<Book>() {
            @Override
            public Predicate toPredicate(Root<Book> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
                Predicate predicate = criteriaBuilder.conjunction();
                if(book != null){
                    if(null != book.getBname() && !"".equals(book.getBname())){
                        predicate.getExpressions().add(criteriaBuilder.like(root.get("bname"),"%"+book.getBname()+"%"));
                    }
                }
                return predicate;
            }
        });
    }

Springboot+bootstrap界面版之增删改查及图片上传

本次案例采取的是spring data jpa和bootstrap3来完成的，并没有使用github提供的分页插件Pagehelper，pagehelper与SSM配合分页在前面博客已经有所讲解。

工程创建

pom依赖

<mysql.version>5.1.44</mysql.version>
<version>${mysql.version}</version>

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.1.10</version>
</dependency>
<dependency>
    <groupId>commons-fileupload</groupId>
    <artifactId>commons-fileupload</artifactId>
    <version>1.3.1</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aspects</artifactId>
</dependency>

application.yml文件配置

server:
  servlet:
    context-path: /springboot
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/mybatis_ssm?useUnicode=true&characterEncoding=utf8
    username: mybatis_ssm
    password: xiaoli
    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

Springboot05Application.java

@EnableTransactionManagement
@SpringBootApplication
public class Springboot05Application {

上传文件映射配置类MyWebAppConfigurer.java

/**
 * 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);
    }
}

后台代码

StringUtils

package com.huang.springboot05.utils;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Set;

public class StringUtils {
    // 私有的构造方法，保护此类不能在外部实例化
    private StringUtils() {
    }

    /**
     * 如果字符串等于null或去空格后等于""，则返回true，否则返回false
     * 
     * @param s
     * @return
     */
    public static boolean isBlank(String s) {
        boolean b = false;
        if (null == s || s.trim().equals("")) {
            b = true;
        }
        return b;
    }
    
    /**
     * 如果字符串不等于null或去空格后不等于""，则返回true，否则返回false
     * 
     * @param s
     * @return
     */
    public static boolean isNotBlank(String s) {
        return !isBlank(s);
    }

    /**
     * set集合转string
     * @param hasPerms
     * @return
     */
    public static String SetToString(Set hasPerms){
        return  Arrays.toString(hasPerms.toArray()).replaceAll(" ", "").replace("[", "").replace("]", "");
    }

    /**
     * 转换成模糊查询所需参数
     * @param before
     * @return
     */
    public static String toLikeStr(String before){
        return isBlank(before) ? null : "%"+before+"%";
    }

    /**
     *    将图片的服务器访问地址转换为真实存放地址
     * @param imgpath    图片访问地址（http://localhost:8080/uploadImage/2019/01/26/20190126000000.jpg）
     * @param serverDir    uploadImage
     * @param realDir    E:/temp/
     * @return
     */
    public static String serverPath2realPath(String imgpath, String serverDir, String realDir) {
        imgpath = imgpath.substring(imgpath.indexOf(serverDir));
        return imgpath.replace(serverDir,realDir);
    }

    /**
     * 过滤掉集合里的空格
     * @param list
     * @return
     */
    public static List<String> filterWhite(List<String> list){
        List<String> resultList=new ArrayList<String>();
        for(String l:list){
            if(isNotBlank(l)){
                resultList.add(l);
            }
        }
        return resultList;
    }

    /**
     * 从html中提取纯文本
     * @param strHtml
     * @return
     */
    public static String html2Text(String strHtml) {
        String txtcontent = strHtml.replaceAll("</?[^>]+>", ""); //剔出<html>的标签
        txtcontent = txtcontent.replaceAll("<a>\\\\s*|\\t|\\r|\\n</a>", "");//去除字符串中的空格,回车,换行符,制表符
        return txtcontent;
    }

    public static void main(String[] args) {
    }
}

PageBean

package com.huang.springboot05.utils;

import javax.servlet.http.HttpServletRequest;
import java.util.Map;

/**
 * 分页工具类
 */
public class PageBean {

    private int page = 1;// 页码

    private int rows = 3;// 页大小

    private int total = 0;// 总记录数

    private boolean pagination = true;// 是否分页
    
//    保存上次查询的参数
    private Map<String, String[]> paramMap;
//    保存上次查询的url
    private String url;
    
    public void setRequest(HttpServletRequest request) {
        String page = request.getParameter("page");
        String rows = request.getParameter("offset");
        String pagination = request.getParameter("pagination");
        this.setPage(page);
        this.setRows(rows);
        this.setPagination(pagination);
        this.setUrl(request.getRequestURL().toString());
        this.setParamMap(request.getParameterMap());
    }

    public PageBean() {
        super();
    }

    public Map<String, String[]> getParamMap() {
        return paramMap;
    }

    public void setParamMap(Map<String, String[]> paramMap) {
        this.paramMap = paramMap;
    }

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public int getPage() {
        return page;
    }

    public void setPage(int page) {
        this.page = page;
    }
    
    public void setPage(String page) {
        if(StringUtils.isNotBlank(page)) {
            this.page = Integer.parseInt(page);
        }
    }

    public int getRows() {
        return rows;
    }

    public void setRows(String rows) {
        if(StringUtils.isNotBlank(rows)) {
            this.rows = Integer.parseInt(rows);
        }
    }

    public int getTotal() {
        return total;
    }

    public void setTotal(int total) {
        this.total = total;
    }

    public void setTotal(String total) {
        if(StringUtils.isNotBlank(total)) {
            this.total = Integer.parseInt(total);
        }
    }

    public boolean isPagination() {
        return pagination;
    }

    public void setPagination(boolean pagination) {
        this.pagination = pagination;
    }
    
    public void setPagination(String pagination) {
        if(StringUtils.isNotBlank(pagination) && "false".equals(pagination)) {
            this.pagination = Boolean.parseBoolean(pagination);
        }
    }
    
    /**
     * 最大页
     * @return
     */
    public int getMaxPage() {
        int max = this.total/this.rows;
        if(this.total % this.rows !=0) {
            max ++ ;
        }
        return max;
    }
    
    /**
     * 下一页
     * @return
     */
    public int getNextPage() {
        int nextPage = this.page + 1;
        if(nextPage > this.getMaxPage()) {
            nextPage = this.getMaxPage();
        }
        return nextPage;
    }
    
    /**
     * 上一页
     * @return
     */
    public int getPreviousPage() {
        int previousPage = this.page -1;
        if(previousPage < 1) {
            previousPage = 1;
        }
        return previousPage;
    }
        

    /**
     * 获得起始记录的下标
     * 
     * @return
     */
    public int getStartIndex() {
        return (this.page - 1) * this.rows;
    }

    @Override
    public String toString() {
        return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", pagination=" + pagination + "]";
    }
}

PageUtil

package com.huang.springboot05.utils;

import java.util.Map;
import java.util.Set;

/**
 * 基于bootstrap3生成分页代码
 */
public class PageUtil {
    public static String createPageCode(PageBean pageBean) {
        StringBuffer sb = new StringBuffer();
        /*
         * 拼接向后台提交数据的form表单
         *     注意：拼接的form表单中的page参数是变化的，所以不需要保留上一次请求的值
         */
        sb.append("<form id=\'pageBeanForm\' action=\'"+pageBean.getUrl()+"\' method=\'post\'>");
        sb.append("<input type=\'hidden\' name=\'page\'>");
        Map<String, String[]> parameterMap = pageBean.getParamMap();
        if(parameterMap != null && parameterMap.size() > 0) {
            Set<Map.Entry<String, String[]>> entrySet = parameterMap.entrySet();
            for (Map.Entry<String, String[]> entry : entrySet) {
                if(!"page".equals(entry.getKey())) {
                    String[] values = entry.getValue();
                    for (String val : values) {
                        sb.append("<input type=\'hidden\' name=\'"+entry.getKey()+"\' value=\'"+val+"\'>");
                    }
                }
            }
        }
        sb.append("</form>");

        if(pageBean.getTotal()==0){
            return "未查询到数据";
        }else{
            sb.append("<li><a href=\'javascript:gotoPage(1)\'>首页</a></li>");
            if(pageBean.getPage()>1){
                sb.append("<li><a href=\'javascript:gotoPage("+pageBean.getPreviousPage()+")\'>上一页</a></li>");
            }else{
                sb.append("<li class=\'disabled\'><a href=\'javascript:gotoPage(1)\'>上一页</a></li>");
            }
            for(int i=pageBean.getPage()-1;i<=pageBean.getPage()+1;i++){
                if(i<1||i>pageBean.getMaxPage()){
                    continue;
                }
                if(i==pageBean.getPage()){
                    sb.append("<li class=\'active\'><a href=\'#\'>"+i+"</a></li>");
                }else{
                    sb.append("<li><a href=\'javascript:gotoPage("+i+")\'>"+i+"</a></li>");
                }
            }
            if(pageBean.getPage()<pageBean.getMaxPage()){
                sb.append("<li><a href=\'javascript:gotoPage("+pageBean.getNextPage()+")\'>下一页</a></li>");
            }else{
                sb.append("<li class=\'disabled\'><a href=\'javascript:gotoPage("+pageBean.getMaxPage()+")\'>下一页</a></li>");
            }
            sb.append("<li><a href=\'javascript:gotoPage("+pageBean.getMaxPage()+")\'>尾页</a></li>");
        }

        /*
         * 给分页条添加与后台交互的js代码
         */
        sb.append("<script type=\'text/javascript\'>");
        sb.append("        function gotoPage(page) {");
        sb.append("            document.getElementById(\'pageBeanForm\').page.value = page;");
        sb.append("            document.getElementById(\'pageBeanForm\').submit();");
        sb.append("        }");
        sb.append("        function skipPage() {");
        sb.append("            var page = document.getElementById(\'skipPage\').value;");
        sb.append("            if(!page || isNaN(page) || parseInt(page)<1 || parseInt(page)>"+pageBean.getMaxPage()+"){");
        sb.append("                alert(\'请输入1~N的数字\');");
        sb.append("                return;");
        sb.append("            }");
        sb.append("            gotoPage(page);");
        sb.append("        }");
        sb.append("</script>");
        return sb.toString();
    }
}

实体类entity

package com.huang.springboot05.entity;

import lombok.ToString;

import javax.persistence.*;

/**
 * @auther 宇晨
 * @company
 * @create 2019-12-01-10:45
 */
@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;

    public Integer getTid() {
        return tid;
    }

    public void setTid(Integer tid) {
        this.tid = tid;
    }

    public String getTname() {
        return tname;
    }

    public void setTname(String tname) {
        this.tname = tname;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public String getImagePath() {
        return imagePath;
    }

    public void setImagePath(String imagePath) {
        this.imagePath = imagePath;
    }
}

dao层

package com.huang.springboot05.repository;

import com.huang.springboot05.entity.Teacher;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;

/**
 * @auther 宇晨
 * @company
 * @create 2019-12-01-11:05
 *
 * 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<T>接口
 */
public interface TeacherDao extends JpaRepository<Teacher, Integer>, JpaSpecificationExecutor<Teacher> {
}

service层

package com.huang.springboot05.service.impl;

import com.huang.springboot05.entity.Teacher;
import com.huang.springboot05.repository.TeacherDao;
import com.huang.springboot05.service.TeacherService;
import com.huang.springboot05.utils.PageBean;
import com.huang.springboot05.utils.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.stereotype.Service;

import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;

/**
 * @auther 宇晨
 * @company
 * @create 2019-12-01-11:08
 */
@Service
public class TeacherServiceImpl implements TeacherService {
    @Autowired
    private TeacherDao teacherDao;
    @Override
    public Teacher save(Teacher teacher) {
        return teacherDao.save(teacher);
    }

    @Override
    public void deleteById(Integer id) {
        teacherDao.deleteById(id);
    }

    @Override
    public Teacher findById(Integer id) {
        return teacherDao.findById(id).get();
    }

    @Override
    public Page<Teacher> listPager(Teacher teacher, PageBean pageBean) {
//        jpa的Pageable分页是从0页码开始
        Pageable pageable = PageRequest.of(pageBean.getPage()-1, pageBean.getRows());
        return teacherDao.findAll(new Specification<Teacher>() {
            @Override
            public Predicate toPredicate(Root<Teacher> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
                Predicate predicate = criteriaBuilder.conjunction();
                if(teacher != null){
                    if(StringUtils.isNotBlank(teacher.getTname())){
                        predicate.getExpressions().add(criteriaBuilder.like(root.get("tname"),"%"+teacher.getTname()+"%"));
                    }
                }
                return predicate;
            }
        },pageable);
    }
}

controler层

package com.huang.springboot05.controller;

import com.huang.springboot05.entity.Teacher;
import com.huang.springboot05.service.TeacherService;
import com.huang.springboot05.utils.PageBean;
import com.huang.springboot05.utils.PageUtil;
import com.huang.springboot05.utils.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;

/**
 * @author 宇晨
 * @company
 * @create  2019-02-20 22:15
 */
@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("&gt:",">")*/);
        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 = "http://localhost:8080/springboot/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/listPage以上是关于springboot对JPA的支持的主要内容，如果未能解决你的问题，请参考以下文章 
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