Mybatis+PageHelper分页工具类
一、添加pom依赖
因为使用了sql的解析工具所以需要引入 jsqlparser jar包。
<!-- https://mvnrepository.com/artifact/com.github.pagehelper/pagehelper-spring-boot-starter --> <dependency> <groupId>com.github.pagehelper</groupId> <artifactId>pagehelper-spring-boot-starter</artifactId> <version>1.3.0</version> </dependency> <!-- https://mvnrepository.com/artifact/com.github.jsqlparser/jsqlparser --> <dependency> <groupId>com.github.jsqlparser</groupId> <artifactId>jsqlparser</artifactId> <version>3.2</version> </dependency>
二、创建分页结果对象
package com.dongliang.lcnorder.util.pagehelper; import lombok.Data; import java.io.Serializable; import java.util.List; /** * @author D-L * @version 1.0.0 * @ClassName PageUtils.java * @Description 分页结果对象 * @createTime 2021-06-15 15:55:00 */ @Data public class PageResult<T extends List> implements Serializable{ private static final long serialVersionUID = -7173074737108151950L; //总记录数 private long total=0; //结果集 private List list; //当前页码 private int pageNum=1; //每页显示条数 private int pageSize=10; //总页数 private int totalPage=1; }
三、分页结果处理工具类
package com.dongliang.lcnorder.util.pagehelper; import com.github.pagehelper.Page; import java.util.List; /** * @author D-L * @version 1.0.0 * @ClassName PageUtils.java * @Description 分页结果处理工具类 * @createTime 2021-06-15 16:15:00 */ public class PageUtils { public static <T extends List> PageResult<T> build(T list){ PageResult<T> result = new PageResult<T>(); if(list == null){ return new PageResult<T>(); } if (list instanceof Page) { Page<T> page = (Page<T>) list; result.setPageNum(page.getPageNum()); result.setPageSize(page.getPageSize()); result.setTotal(page.getTotal()); result.setTotalPage(page.getPages()); result.setList(list); } return result; } }
四、请求响应模板
package com.dongliang.lcnorder.util.response; import lombok.AllArgsConstructor; import lombok.Data; import lombok.NoArgsConstructor; import java.io.Serializable; /** * @author D-L * @version 1.0.0 * @ClassName ResponseParams.java * @Description 请求响应模板 * @createTime 2021-06-15 16:41:00 */ @Data @NoArgsConstructor @AllArgsConstructor public class ResponseParams<T> implements Serializable { private static final long serialVersionUID = -7173074737108454L; //状态（0或1） private String status = "0"; // 错误码 private String code = "0x00000000"; //描述信息（成功或失败原因） private String message = ""; //接口名 private String remark = ""; private T data; public ResponseParams success(){ this.status = "1"; this.message = "【调用成功】"; this.code = "0x00000000"; return this; } public ResponseParams success(String code , T data){ this.status = "1"; this.message ="【调用成功】"; this.code = code; this.data = data; return this; } public ResponseParams error(){ this.status = "0"; this.message = "【调用失败】"; this.code = "500"; return this; } public ResponseParams error(String code){ this.status = "0"; this.message = "【调用失败】"; this.code = code; return this; } public ResponseParams(String remark) { this.remark = remark; }
public ResponseParams(T data) {
this.data = data;
}
}
五、自定义异常
package com.dongliang.lcnorder.util.exception; import lombok.Data; import lombok.EqualsAndHashCode; import lombok.NoArgsConstructor; /** * @author D-L * @version 1.0.0 * @ClassName ResponseControllerAdvice.java * @Description 自定义通用异常 * @createTime 2021-06-16 09:37:00 */ @Data @EqualsAndHashCode(callSuper=false) @NoArgsConstructor public class CustomizeException extends RuntimeException { private static final long serialVersionUID = -1514051287932579564L; private String code; private String msg; private String description; public CustomizeException(String msg) { super(msg); this.msg = msg; } public CustomizeException(String code, String msg, String description) { super(msg); this.code = code; this.msg = msg; this.description = description; } }
六、处理全局异常
package com.dongliang.lcnorder.util.response; import com.dongliang.lcnorder.util.exception.CustomizeException; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.ObjectMapper; import org.springframework.core.MethodParameter; import org.springframework.http.MediaType; import org.springframework.http.converter.HttpMessageConverter; import org.springframework.http.server.ServerHttpRequest; import org.springframework.http.server.ServerHttpResponse; import org.springframework.web.bind.annotation.RestControllerAdvice; import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice; /** * @author D-L * @version 1.0.0 * @ClassName ResponseControllerAdvice.java * @Description 处理全局异常 * @createTime 2021-06-16 09:37:00 */ @RestControllerAdvice(basePackages = {"com.dongliang.lcnorder.controller"}) public class ResponseControllerAdvice implements ResponseBodyAdvice<Object> { @Override public boolean supports(MethodParameter methodParameter, Class<? extends HttpMessageConverter<?>> aClass) { // 如果接口返回的类型本身就是 ResponseParams 那就没有必要进行额外的操作，返回false return !methodParameter.getGenericParameterType().equals(ResponseParams.class); } @Override public Object beforeBodyWrite(Object data, MethodParameter methodParameter, MediaType mediaType, Class<? extends HttpMessageConverter<?>> aClass, ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) { // String类型不能直接包装，所以要进行些特别的处理 if (methodParameter.getGenericParameterType().equals(String.class)) { ObjectMapper objectMapper = new ObjectMapper(); try { // 将数据包装在 ResponseParams 里后，再转换为json字符串响应给前端 return objectMapper.writeValueAsString(new ResponseParams<>(data)); } catch (JsonProcessingException e) { // CustomizeException 为自定义异常 throw new CustomizeException("返回String类型错误"); } } // 将原本的数据包装在 ResponseParams 里 return new ResponseParams<>(data); } }
七、接口入参DTO
package com.dongliang.lcnorder.entity.dto; import lombok.Data; import javax.validation.constraints.NotNull; import java.io.Serializable; /** * @author D-L * @version 1.0.0 * @ClassName UserListDto.java * @Description 用户列表入参dto * @createTime 2021-06-15 22:31:00 */ @Data public class UserListDto implements Serializable { private static final long serialVersionUID = 1L; @NotNull(message = "页码不能为空") private Integer pageNum; @NotNull(message = "每页条数不能为空") private Integer pageSize; }
八、使用
/** * 获取用户列表 * @param userListDto 入参 * @return */ @PostMapping("/getUser") public ResponseParams getUser(@Validated @RequestBody UserListDto userListDto){ ResponseParams responseParams = new ResponseParams("查询用户列表"); PageHelper.startPage(userListDto.getPageNum(),userListDto.getPageSize()); List<Users> users = orderService.getUser(); PageResult<List<Users>> pageResult = PageUtils.build(users); return responseParams.success("200" , pageResult); }
九、结果
十、异常结果
