第1步:定义线程容器收纳HttpHeaders和HttpStatus
java
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
public class ResponseUtils {
private static ThreadLocal<HttpHeaders> ThreadLocalHeaders = new InheritableThreadLocal<>();
private static ThreadLocal<HttpStatus> ThreadLocalStatus = new InheritableThreadLocal<>();
public static void addHeaders(String key, String value) {
if (ThreadLocalHeaders.get() == null) {
ThreadLocalHeaders.set(new HttpHeaders());
}
ThreadLocalHeaders.get().add(key, value);
}
public static void setResponseCode(HttpStatus httpStatus) {
ThreadLocalStatus.set(httpStatus);
}
public static HttpHeaders getHeaders() {
return ThreadLocalHeaders.get();
}
public static HttpStatus getResponseCode() {
return ThreadLocalStatus.get();
}
public static void clear() {
if (ThreadLocalHeaders.get() != null) {
ThreadLocalHeaders.remove();
}
if (ThreadLocalStatus.get() != null) {
ThreadLocalStatus.remove();
}
}
}
第2步:分页信息 转储到 线程容器 方法的封装
java
import com.github.pagehelper.PageInfo;
import com.zhangziwa.practisesvr.utils.response.ResponseUtils;
public class PageHeaderUtils {
private static final String PAGE_NUM = "page_num"; // 当前第几页
private static final String PAGE_SIZE = "page_size"; // 每页显示的条数
private static final String PREV_PAGE = "prev_page"; // 上一页页码
private static final String NEXT_PAGE = "next_page"; // 下一页页码
private static final String TOTAL_COUNT = "total_count"; // 总条数
private static final String TOTAL_PAGE = "total_page"; // 总页数
public static <E> void setPageHeader(PageInfo<E> page) {
if (page == null) {
return;
}
ResponseUtils.addHeaders(PAGE_NUM, String.valueOf(page.getPageNum()));
ResponseUtils.addHeaders(PAGE_SIZE, String.valueOf(page.getPageSize()));
ResponseUtils.addHeaders(TOTAL_COUNT, String.valueOf(page.getTotal()));
ResponseUtils.addHeaders(TOTAL_PAGE, String.valueOf(page.getPages() == 0 ? 1 : page.getPages()));
// page.getPages()=1表示就1页,前后页都不存在,故也算特殊场景.也为了page.getPages()+1和page.getPages()-1不会对[1,page.getPages()]越界
if (page.getPages() == 0 || page.getPages() == 1) {
ResponseUtils.addHeaders(PREV_PAGE, "");
ResponseUtils.addHeaders(NEXT_PAGE, "");
} else if (page.getPageNum() == 1) {
ResponseUtils.addHeaders(PREV_PAGE, "");
ResponseUtils.addHeaders(NEXT_PAGE, String.valueOf(page.getPages() + 1));
} else if (page.getPageNum() == page.getPages()) {
ResponseUtils.addHeaders(PREV_PAGE, String.valueOf(page.getPages() - 1));
ResponseUtils.addHeaders(NEXT_PAGE, "");
} else {
ResponseUtils.addHeaders(PREV_PAGE, String.valueOf(page.getPages() - 1));
ResponseUtils.addHeaders(NEXT_PAGE, String.valueOf(page.getPages() + 1));
}
}
}
第3步:分页查询,HttpHeaders和HttpStatus收集到线程容器中
java
public List<Student> listStudents(Integer pageNum, Integer PageSize) {
PageHelper.startPage(PageUtils.getPageNum(pageNum), PageUtils.getPageSize(PageSize), PageUtils.isQueryTotalCount());
PageHelper.orderBy("age asc");
List<Student> students = userMapper.listStudents();
PageInfo<Student> studentPageInfo = PageInfo.of(students);
// 收集分页信息到 ThreadLocal
PageHeaderUtils.setPageHeader(studentPageInfo);
// 收集HttpStatus到 ThreadLocal
// ResponseUtils.setResponseCode(num2HttpStatus("200")); // 为了使用一下num2HttpStatus方法
ResponseUtils.setResponseCode(HttpStatus.OK);
return students;
}
java
public class HttpStatusUtils {
public static HttpStatus num2HttpStatus(String num) {
HttpStatus httpStatus = HttpStatus.NOT_FOUND;
for (HttpStatus status : HttpStatus.values()) {
if (Integer.parseInt(num) == status.value()) {
return status;
}
}
return httpStatus;
}
}
第4步:controller层需为@RestController Restful接口
java
@RestController
@Slf4j
public class SearchController {
@Autowired
UserService userService;
@RequestMapping(value = "/getAllStudents", method = RequestMethod.GET)
public List<Student> login() {
List<Student> students = userService.listStudents(1, 10);
students.forEach(System.out::println);
return students;
}
}
第5步:线程容器收纳HttpHeaders和HttpStatus添加到ServerHttpResponse
java
@ControllerAdvice
public class HttpResponseBodyAdvice implements ResponseBodyAdvice {
@Override
public boolean supports(MethodParameter returnType, Class converterType) {
return true;
}
@Override
public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType, Class clazz,
ServerHttpRequest request, ServerHttpResponse response) {
HttpHeaders headers = response.getHeaders();
// 分页信息添加到ServerHttpResponse
HttpHeaders headersContext = ResponseUtils.getHeaders();
if (nonNull(headersContext) && !headersContext.isEmpty()) {
headers.addAll(headersContext);
}
// 状态码添加到ServerHttpResponse
if (nonNull(ResponseUtils.getResponseCode())) {
response.setStatusCode(ResponseUtils.getResponseCode());
}
return body;
}
}
第6步:测试结果