springboot jpa 分页查询(增删改查)总结

Posted 2022-05-12 栗子~~

springboot  jpa 分页查询(增删改查)总结

         jpa 大白话可以把它理解为一个插件，在开发过程中，目的在于可以提供你更加简单的编程模型，简单方便 。

        JPA框架中支持大数据集、事务、并发等容器级事务，使得 JPA 超越了简单持久化框架的局限，在企业级开发中发挥出更大的作用。

      首先添加jpa的 起步依赖

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

    application.properties配置文件添加

#\\u6ce8\\u610f\\u4e2d\\u6587\\u4e71\\u7801
spring.datasource.url=jdbc:oracle:thin:@192.168.0.25:1521:orcl
spring.datasource.username=quartz
spring.datasource.password=quartz
spring.datasource.driver-class-name=oracle.jdbc.driver.OracleDriver
# Specify the DBMS
spring.jpa.database=ORACLE
# Show or not log for each sql query
spring.jpa.show-sql=true
# DDL mode. This is actually a shortcut for the "hibernate.hbm2ddl.auto" property. Default to "create-drop" when using an embedded database, "none" otherwise.
spring.jpa.hibernate.ddl-auto=update
# Hibernate 4 naming strategy fully qualified name. Not supported with Hibernate 5.
spring.jpa.hibernate.naming.strategy=org.hibernate.cfg.ImprovedNamingStrategy
# stripped before adding them to the entity manager)
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.Oracle9Dialect

以上是使用jpa的前置条件,接下来讲述jpa 的具体代码。 

1、自定义sql查询

首先 dao层java代码继承JpaRepository<T, String>,JpaSpecificationExecutor<T>

其中JpaRepository<T, String>里的String代表的是表id的类型，建议该位置跟表id的类型统一

  /**
     * 自定义sql
     * **/
    @Query(value  ="select * from qrtz_db t where t.id = ?1",nativeQuery = true)
    QrtzDb selectDb(String dbId);

    @Query(value = "select * from qrtz_db",nativeQuery = true)
    List<QrtzDb> selectDbs();

    @Query(value = "update qrtz_db set url =?2 where id = ?1 ",nativeQuery = true)
    @Modifying
    int updateDb(String id,String urlTest);

    @Query(value = "select * from qrtz_db t where (t.dbname like '%'||?1||'%' or ?1='')",nativeQuery = true)
    List<QrtzDb> list(String content);

实体类:注意注解的应用(重点),其中如果并不是表中的字段用 @Transient注解进行标识，否则会出现错误

@Entity
@Table(name = "TABLE_LOG")
public class TableLog 
    @Id
    @Column(name = "LOGID")
    private String logid;
    @Column(name = "TABLENAME")
    private String tablename;
    @Column(name = "MSG")
    private String msg;
    @Column(name = "ERRCOUNT")
    private Integer errcount;
    @Column(name = "UPDATELOG")
    private Date updatelog;
    @Transient
    private Date startDay;
    @Transient
    private Date endDay;
    @Column(name = "MONTHDAY")
    private Date monthday;
    @Column(name = "WORKMSG")
    private String workMsg;

    ...Set Get...

jpa 自带增删改查

@Service("dbService")
@Transactional
public class DbServiceImpl implements DbService 
    @Autowired
    private DbDao dbDao;

    @Override
    public void add(QrtzDb qrtzDb) 
        /*有id 改，无id 增*/
        dbDao.save(qrtzDb);
    

    /*删*/
    @Override
    public void delete(String id) 
        dbDao.delete(id);
    
   

jpa的分页查询

Controller层

    @ApiOperation(value="日志列表")
    @PostMapping("/list")
    public Result list(TableLog tablelog, Integer pageNo, Integer pageSize) 
         LOGGER.info("日志列表");
        //pageNo 页数 pageSize 每页条数 Sort.Direction.DESC 降序  最后一个参数代表降序字段
        Pageable pageRequest = new PageRequest(pageNo-1,pageSize, Sort.Direction.DESC,"updatelog");
        Page<TableLog> page = logService.getlist(tablelog,pageRequest);
        Map map = new HashMap();

        map.put("page",page);
        if (StringUtils.isNotBlank(tablelog.getWorkMsg()))
            map.put("workMsg",tablelog.getWorkMsg());
        
        if(tablelog.getUpdatelog() == null)
            map.put("updateDay","");
        else
            map.put("updateDay",tablelog.getUpdatelog());

        

        return Result.ok(map);
    

service层

 @Override
    public Page<TableLog> getlist( final TableLog tablelog, Pageable pageRequest) 

        Page<TableLog> page = logDao.findAll(new Specification<TableLog>() 
            @Override
            public Predicate toPredicate(Root<TableLog> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) 
                List<Predicate> list = new ArrayList<Predicate>();
                if (StringUtils.isNotBlank(tablelog.getWorkMsg()))
                    //相当于 like
                    list.add(criteriaBuilder.like(root.get("workMsg").as(String.class),"%"+tablelog.getWorkMsg()+"%"));
                
                if (tablelog.getStartDay() != null)
                    try 
                        SimpleDateFormat dd = new SimpleDateFormat("yyyy/MM/dd");
                        //相当于between and
                        list.add(criteriaBuilder.between(root.get("updatelog").as(Date.class),  dd.parse(dd.format(tablelog.getStartDay())),  dd.parse(dd.format(tablelog.getEndDay()))));
                    catch (Exception e)
                        e.printStackTrace();
                        LOGGER.error("执行日期转换出错");
                    
                
                if (tablelog.getUpdatelog() != null)
                    try
                        StringBuffer sb = new StringBuffer();
                        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy/MM/dd HH");
                        SimpleDateFormat dd = new SimpleDateFormat("yyyy/MM/dd");
                        //当前时间
                        String time = simpleDateFormat.format(tablelog.getUpdatelog());
                        String t[] = time.split(" ");
                        if (Integer.parseInt(t[1]) < 23)
                            t[1] =  String.valueOf(Integer.parseInt(t[1]) + 1);
                            sb.append(t[0]);
                            sb.append(" "+t[1]);
                        else
                            Calendar calendar = Calendar.getInstance();
                            calendar.setTime(dd.parse(t[0]));
                            int day = calendar.get(Calendar.DATE);
                            calendar.set(Calendar.DATE,day+1);
                            String dat1 = simpleDateFormat.format(calendar.getTime());
                            sb.append(dat1);
                        
                        //下一小时时间
                        String time1 = sb.toString();


                    /*list.add(criteriaBuilder.equal(root.get("updatelog").as(Date.class),tablelog.getUpdatelog()));*/
                    list.add(criteriaBuilder.between(root.get("updatelog").as(Date.class),simpleDateFormat.parse(time),simpleDateFormat.parse(time1)));
                    catch(Exception e)
                        e.printStackTrace();
                        LOGGER.error("执行日期转换出错");
                    
                
                //重点
                Predicate[] p = new Predicate[list.size()];
                return criteriaBuilder.and(list.toArray(p));
            
        , pageRequest);
        return page;
    

以上是我自己总结的jpa相关代码