该篇博客记录采用pagehelper分页插件实现Mybatis分页功能
一、依赖
- pom.xml
com.github.pagehelper
pagehelper-spring-boot-starter
1.2.5
二、配置
- application.yml
# pagehelper
pagehelper:
helperDialect: mysql
reasonable: true
supportMethodsArguments: true
params: count=countSql- CURD通用接口封装
public interface CurdService {
/**
* 分页查询
* 这里统一封装了分页请求和结果，避免直接引入具体框架的分页对象, 如MyBatis或JPA的分页对象
* 从而避免因为替换ORM框架而导致服务层、控制层的分页接口也需要变动的情况，替换ORM框架也不会
* 影响服务层以上的分页接口，起到了解耦的作用
* @param pageRequest 自定义，统一分页查询请求
* @return PageResult 自定义，统一分页查询结果
*/
PageResult findPage(PageRequest pageRequest);
} - 分页请求封装
public class PageRequest {
/**
* 当前页码
*/
private int pageNum = 1;
/**
* 每页数量
*/
private int pageSize = 10;
/**
* 查询参数
*/
private Map params = new HashMap<>();
public int getPageNum() {
return pageNum;
}
public void setPageNum(int pageNum) {
this.pageNum = pageNum;
}
public int getPageSize() {
return pageSize;
}
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
public Map getParams() {
return params;
}
public void setParams(Map params) {
this.params = params;
}
public Object getParam(String key) {
return getParams().get(key);
}
} - 分页结果封装
public class PageResult {
/**
* 当前页码
*/
private int pageNum;
/**
* 每页数量
*/
private int pageSize;
/**
* 记录总数
*/
private long totalSize;
/**
* 页码总数
*/
private int totalPages;
/**
* 分页数据
*/
private List content;
public int getPageNum() {
return pageNum;
}
public void setPageNum(int pageNum) {
this.pageNum = pageNum;
}
public int getPageSize() {
return pageSize;
}
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
public long getTotalSize() {
return totalSize;
}
public void setTotalSize(long totalSize) {
this.totalSize = totalSize;
}
public int getTotalPages() {
return totalPages;
}
public void setTotalPages(int totalPages) {
this.totalPages = totalPages;
}
public List getContent() {
return content;
}
public void setContent(List content) {
this.content = content;
}
}- 分页助手封装
public class MybatisPageHelper {
public static final String findPage = "findPage";
/**
* 分页查询, 约定查询方法名为 “findPage”
* @param pageRequest 分页请求
* @param mapper Dao对象，MyBatis的 Mapper
* @param args 方法参数
* @return
*/
public static PageResult findPage(PageRequest pageRequest, Object mapper) {
return findPage(pageRequest, mapper, findPage);
}
/**
* 调用分页插件进行分页查询
* @param pageRequest 分页请求
* @param mapper Dao对象，MyBatis的 Mapper
* @param queryMethodName 要分页的查询方法名
* @param args 方法参数
* @return
*/
@SuppressWarnings({ "unchecked", "rawtypes" })
public static PageResult findPage(PageRequest pageRequest, Object mapper, String queryMethodName, Object... args) {
// 设置分页参数
int pageNum = pageRequest.getPageNum();
int pageSize = pageRequest.getPageSize();
PageHelper.startPage(pageNum, pageSize);
// 利用反射调用查询方法
Object result = ReflectionUtils.invoke(mapper, queryMethodName, args);
return getPageResult(pageRequest, new PageInfo((List) result));
}
/**
* 将分页信息封装到统一的接口
* @param pageRequest
* @param page
* @return
*/
private static PageResult getPageResult(PageRequest pageRequest, PageInfo pageInfo) {
PageResult pageResult = new PageResult();
pageResult.setPageNum(pageInfo.getPageNum());
pageResult.setPageSize(pageInfo.getPageSize());
pageResult.setTotalSize(pageInfo.getTotal());
pageResult.setTotalPages(pageInfo.getPages());
pageResult.setContent(pageInfo.getList());
return pageResult;
}
}- HTTP返回结果封装
public class HttpResult {
private int code = 200;
private String msg;
private Object data;
public static HttpResult error() {
return error(HttpStatus.SC_INTERNAL_SERVER_ERROR, "未知异常，请联系管理员");
}
public static HttpResult error(String msg) {
return error(HttpStatus.SC_INTERNAL_SERVER_ERROR, msg);
}
public static HttpResult error(int code, String msg) {
HttpResult r = new HttpResult();
r.setCode(code);
r.setMsg(msg);
return r;
}
public static HttpResult ok(String msg) {
HttpResult r = new HttpResult();
r.setMsg(msg);
return r;
}
public static HttpResult ok(Object data) {
HttpResult r = new HttpResult();
r.setData(data);
return r;
}
public static HttpResult ok() {
return new HttpResult();
}
public int getCode() {
return code;
}
public void setCode(int code) {
this.code = code;
}
public String getMsg() {
return msg;
}
public void setMsg(String msg) {
this.msg = msg;
}
public Object getData() {
return data;
}
public void setData(Object data) {
this.data = data;
}
}三、实现
- SysUserController.java
@RestController
@RequestMapping("/user")
public class SysUserController {
@Autowired
private SysUserService sysUserService;
@PostMapping(value="/findPage")
public HttpResult findPage(@RequestBody PageRequest pageRequest) {
return HttpResult.ok(sysUserService.findPage(pageRequest));
}
}- SysUserService.java
public interface SysUserService extends CurdService {
} - SysUserMapper.java
public interface SysUserMapper {
List findPage();
} - SysUserServiceImpl.java
//经过对分页查询业务的封装，只需调用MybatisPageHelper.findPage(pageRequest, sysUserMapper)即可实现分页查询功能
@Service
public class SysUserServiceImpl implements SysUserService {
@Autowired
private SysUserMapper sysUserMapper;
@Override
public PageResult findPage(PageRequest pageRequest) {
return MybatisPageHelper.findPage(pageRequest, sysUserMapper);
}
}- SysUserMapper.xml
id, name, nick_name, avatar, password, salt, email, mobile, status, dept_id, create_by,
create_time, last_update_by, last_update_time, del_flag
四、测试
- 关于如何集成Mybatis，参考：mybatis 生成代码配置 mybatis-generator:generate 的使用详解，前半部分有详细的POM代码