我就废话不多说了，大家还是直接看代码吧

//执行的是删除信息的操作
 String a=request.getParameter("name");
 a = URLEncoder.encode(a, "ISO-8859-1");
 String name = URLDecoder.decode(a, "UTF-8");
 String num=request.getParameter("num");
 System.out.println("name:"+name+"num:"+num);
 String sql="delete from person_info where name=? and num=?";
 String sz[]={name,num};
 JdbcUtils.update(sql, sz);

 //刷新操作\

 String sqls="select * from person_info";
 ResultSet rs=JdbcUtils.select(sqls, null);
 ArrayList<Person_info> list=new ArrayList<Person_info>();
 try {
 while(rs.next()){
 Person_info pi=new Person_info(rs.getString(1), rs.getString(2), rs.getString(3), rs.getString(4), rs.getString(5), rs.getString(6));
 list.add(pi);
 }
 request.setAttribute("list", list);
 request.getRequestDispatcher("Personnel_definition.jsp").forward(request, response);
 } catch (SQLException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 } 
  
 }

image.png

补充知识：关于分页时怎么实现当本页面最后一条记录被删除时,自动向上一个页面跳转的实现（java实现）

问题详解

在做批量删除时，发现若批量删除整页时，会自动跳到第一页首页，而不是返回删除当前页的上一页，不符合产品要求且使界面交互不好，给用户带来糟糕体验。

思路详解

在controller层传参时要考虑到不仅要传入需要删除的id集合，同时传入pageSize,pageNum以及总条数集合的查询条件（如：本示例会传入groupId(分组id)）,在删除成功后初始化当前页，先根据查询条件查询出总条数数量，在pageSize不等于null或为0的情况下。算出余数[（pageSize*pageNum-count）%pageSize ].若余数为0，则当前页等于pageNum-1;若余数不为0，则当前页=pageNum.将结果当前页传给前台即可。

后台代码实现

controller层#

@Api(description = "分组下的学生",value = "分组下的学生")
@RestController
@RequestMapping("studentGroup")
public class StudentGroupController {
 @Autowired
 private RestStudentGroupService restStudentGroupService;
 
 @RequestMapping(value = "deleteGroupStudent",method = RequestMethod.POST)
 @ApiOperation(value = "删除分组中的学生",notes = "删除分组中的学生")
 public ResponseObj deleteGroupStudent(@RequestParam(value = "groupId",required = true)Long groupId,
   @RequestParam(value = "ids",required = true)String ids,
   @RequestParam(value = "pageSize",required = false)Integer pagesize,
   @RequestParam(value = "pageNum",required = false)Integer pageNum){
 
 return restStudentGroupService.deleteGroupStudent(groupId,ids,pagesize,pageNum);
 }
 }

service层#

@FeignClient(value = ServiceName.VALUE)
public interface RestStudentGroupService {
 
 @RequestMapping(value = "/school/cloud/student/deleteGroupStudent",method = RequestMethod.POST)
 public ResponseObj deleteGroupStudent(@RequestParam(value = "groupId")Long groupId,
   @RequestParam(value = "ids")String ids,
   @RequestParam(value = "pageSize")Integer pagesize,
   @RequestParam(value = "pageNum")Integer pageNum);
   }

serviceImpl层#

@Service
public class RestStudentGroupServiceImpl implements RestStudentGroupService {
 
 @Autowired
 private DubboStudentGroupService dubboStudentGroupService ;
 @Override
 public ResponseObj deleteGroupStudent(Long groupId,String ids,Integer pageSize,Integer pageNum) {
 
 List<Long> idList = TextUtils.split(ids);
 if(groupId == null || idList== null || idList.size() == 0){
 ResponseObj responseObj = ResponseObj.ERROR("参数错误");
 responseObj.setSuccess(true);
 return responseObj;
 }
 ServiceResult<Long> serviceResult = dubboStudentGroupService .deleteCorpGroup(idList, groupId);
 if(!serviceResult.getSuccess()){
 throw new RuntimeException("分组下学生查询失败");
 }
 //应前端要求加此dto，封装传给前台的当前页属性
 CurrenPageDto currenPageDto=new CurrenPageDto();
 //初始化当前页
 Integer currentPage = 1;
 //查出该分组id下的学生数量
 ServiceResult<Long> itemCountLongs = dubboStudentGroupService.getTotalCount(groupId);
 Long itemCountLong= itemCountLongs.getResult();
 Integer itemCount = itemCountLong!=null ? itemCountLong.intValue() : 0;
 //"查询到学生数量：{},pageSize:{}", itemCount,pageSize;
 if(pageSize != null && pageSize != 0){
 //算出余数
 Integer temp = (pageNum*pageSize-itemCount)%pageSize;
 if(temp == 0){
 //余数为0的话就pageNum-1
 currentPage = (pageNum - 1) == 0 ? 1 : (pageNum -1) ;
 }else {
 //余数不为0则等于pageNum
 currentPage = pageNum;
 }
 currenPageDto.setPresentPage(currentPage);
 }
 ResponseObj responseObj = ResponseObj.SUCCESS();
 responseObj.setData(currenPageDto);
 return responseObj;
 }
}

dubbo接口的service层#

①：//删除分组下的学生
ServiceResult<Long> deleteCorpGroup(List<Long> idList,Long groupId);
②：//根据条件查询对应的条目总数
ServiceResult<Long> getTotalCount(Long groupId);

dubbo接口的serviceImpl层#

`①：``//删除分组下的学生`

`@Override`

`public` `ServiceResult<Long> deleteCorpGroup(List<Long> idList, Long groupId) {`

`ServiceResult<Long> result =` `new` `ServiceResult<>();`

`try` `{`

`studentGroupDao.deleteCorpGroup(idList, groupId);`

`}` `catch` `(Exception e) {`

`log.error(``"调用{}方法 异常"``,` `"[RestStudentGroupServiceImpl .deleteCorpGroup]"``);`

`log.error(``"方法使用参数：[idList:{},groupId:{}]"``, idList, groupId);`

`log.error(``"异常信息：{}"``, e);`

`result.setErrMessage(``"调用deleteCorpGroup方法异常，异常信息："` `+ e.getMessage());`

`}`

`return` `result;`

`}`

`②：``//根据条件查询对应的条目总数`

`@Override`

`public` `ServiceResult<Long> getTotalCount(Long groupId) {`

`ServiceResult<Long> result =` `new` `ServiceResult<>();`

`try` `{`

`long` `count = studentGroupDao.getFindCorpGroupDirectoryCount(groupId);`

`result.setResult(count);`

`}` `catch` `(Exception e) {`

`log.error(``"调用{}方法 异常"``,` `"[RestStudentGroupServiceImpl .getTotalCount]"``);`

`log.error(``"方法使用参数：[groupId:{}]"``, groupId);`

`log.error(``"异常信息：{}"``, e);`

`result.setErrMessage(``"调用getTotalCount方法异常，异常信息："` `+ e.getMessage());`

`}`

`return` `result;`

`}`

 |

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<textarea style="margin: 0px; padding: 0px; outline: none; font: 16px / 24px tahoma, arial, 宋体;"></textarea>

#dubbo接口的dao层#

`①：``//删除分组下的学生`

`Long deleteCorpGroup(``@Param``(value =` `"idList"``) List<Long> idList,``@Param``(value =` `"groupId"``) Long groupId);`

`②：``//根据条件查询对应的条目总数`

`Long getFindCorpGroupDirectoryCount(``@Param``(value =` `"groupId"``) Long groupId);`

 |

dubbo接口的sql#

①：//删除分组下的学生
 <delete id="deleteCorpGroup">
 delete from student_group where group_id = #{groupId} and id in
 <foreach collection="idList" index="index" separator="," item="id"
  open="(" close=")">
 #{id}
 </foreach>
 </delete>
②：//根据条件查询对应的条目总数
 <select id="getFindCorpGroupDirectoryCount" resultType="long">
 SELECT COUNT(1)
 FROM student_group 
 where group_id = #{groupId}
 </select>

Entity类(学生分组类)#（get,set函数省略）

|

public class StudentGroup implements java.io.Serializable {

/**

*

*/

private static final long serialVersionUID = 1L;

/**

* @描述:

* @字段:id BIGINT(19)

*/

private Long StudentGroupId;

/**

* @描述:

* @字段:group_id BIGINT(19)

*/

private Long groupId;

/**

* @描述:

* @字段:id BIGINT(19)

* 此id为学生表id

*/

private Long id;

/**

* @描述:创建时间

* @字段:create_time DATETIME(19)

*/

private java.util.Date createTime;

* @描述:创建人用户名

* @字段:create_user_name VARCHAR(``30``)

*/

private String createUserName;

/**

* @描述:创建人用户ID

* @字段:create_user_id BIGINT(19)

*/

private Long createUserId;

/**

* @描述:更新时间

* @字段:update_time DATETIME(19)

*/

private java.util.Date updateTime;

* @描述:更新人用户名

* @字段:update_user_name VARCHAR(``30``)

*/

private String updateUserName;

/**

* @描述:更新人用户ID

* @字段:update_user_id BIGINT(19)

*/

private Long updateUserId;

}

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<textarea style="margin: 0px; padding: 0px; outline: none; font: 16px / 24px tahoma, arial, 宋体;"></textarea>

#Entity类(学生类)#（get,set函数省略）
```c
`public` `clas` `Student` `implements` `java.io.Serializable {`

`/**`

`*`

`*/`

`private` `static` `final` `long` `serialVersionUID = 1L;`

`private` `Long id;`

`private` `String name ;`

`private` `Integer age;`