背景
使用了restful的小伙伴对于导出这些需求本能就是拒绝的~破坏了restful的url的一致性【严格矫正 不是http json就是restful 很多小伙伴都会吧暴露出一个json就直接称为restful 】
正如上文的代码生成器 我们会批量生成一堆代码 其中绝大部分都是RestController
public abstract class AbstractRestController<V extends Vo, S extends So, PK extends Serializable> { protected Class<V> voClazz; @Autowired private Service<V, S, PK> service; public AbstractRestController() { TypeToken<V> voType = new TypeToken<V>(getClass()) { }; voClazz = (Class<V>) voType.getRawType(); } @PostMapping() @ApiOperation(value = "新建实体", notes = "") public Result add(@RequestBody V vo) { service.saveSelective(vo); return ResultGenerator.genSuccessResult(); } @DeleteMapping("/{id}") @ApiOperation(value = "删除实体", notes = "") public Result delete(@PathVariable PK id) { service.deleteById(id); return ResultGenerator.genSuccessResult(); } @PutMapping @ApiOperation(value = "更新实体", notes = "") public Result update(@RequestBody V vo) { service.updateByPrimaryKeySelective(vo); return ResultGenerator.genSuccessResult(); } @GetMapping @ApiOperation(value = "获取实体列表", notes = "") public Result list(S so) { PageHelper.startPage(so.getCurrentPage(), so.getPageSize()); List<V> list = service.findAll(); PageInfo pageInfo = new PageInfo(list); excelExportParam(); return ResultGenerator.genSuccessResult(pageInfo); } protected void excelExportParam() { ExportParams ep = new ExportParams(null, "数据"); ExcelExportParam<V> param = new ExcelExportParam<>(); param.setClazz(voClazz); param.setExcelExport(ExcelExport.NormalExcel); param.setExportParams(ep); param.setFileName("文件.xls"); F6Static.setExcelExportParam(param); } @GetMapping("/{id}") @ApiOperation(value = "获取单个实体", notes = "") public Result detail(@PathVariable PK id) { V vo = service.findById(id); return ResultGenerator.genSuccessResult(vo); } @DeleteMapping("/batch") @ApiOperation(value = "批量删除实体", notes = "") public Result batchDelete(@RequestParam String ids) { service.deleteByIds(ids); return ResultGenerator.genSuccessResult(); } @GetMapping("/batch") @ApiOperation(value = "批量获取实体", notes = "") public Result batchDetail(@RequestParam String ids) { List<V> vos = service.findByIds(ids); return ResultGenerator.genSuccessResult(vos); } @PostMapping("/batch") @ApiOperation(value = "批量新建实体", notes = "") public Result add(@RequestBody List<V> vos) { service.save(vos); return ResultGenerator.genSuccessResult(); } @GetMapping("/count") @ApiOperation(value = "获取实体数目", notes = "") public Result count(@RequestBody V v) { int count = service.selectCount(v); return ResultGenerator.genSuccessResult(count); }那么导出如何做呢？【其实可以理解成导出就是数据的展示 不过此时结果不是json而已】
抛出一个问题那么登录登出呢？传统的方案都是login logout 那么换成restful资源的思路是啥呢？
提示： 登录就是session的新建 登出就是session的删除
实现
基于上述思路 我们自然就想到了那么我们只需要对同一个url返回多种结果不就OK了？【pdf一个版本 json一个版本 xml一个版本 xls一个版本】
bingo！这个是内容协商器的由来
内容协商器并不是Spring创造出来的 事实上这个从http头里面也能看出
1.比如给英语客户返回英语页面 过于客户返回汉语页面
HTTP 协议中定义了质量值(简称 q 值)，允许客户端为每种偏好类别列出多种选项，并为每种偏好选项关联一个优先次序。
Accept-Language: en;q=0.5, fr;q=0.0, nl;q=1.0, tr;q=0.0
其中 q 值的范围从 0.0 ~ 1.0（0.0 是优先级最低的，而 1.0 是优先级最高的）。
注意，偏好的排列顺序并不重要，只有与偏好相关的 q 值才是重要的
2.那么还有其他的一些参数 比如 accept-header
通常是先内容协商器有如下几种方案
1.使用Accept header:
这一种为教科书中通常描述的一种,理想中这种方式也是最好的,但如果你的资源要给用户直接通过浏览器访问(即html展现),那么由于浏览器的差异,发送上来的Accept Header头将是不一样的. 将导致服务器不知要返回什么格式的数据给你. 下面是浏览器的Accept Header
chrome: Accept:application/xml,application/xhtml+xml,textml;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 firefox: Accept:text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 IE8: Accept:image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash, application/x-silverlight, application/x-ms-application, application/x-ms-xbap, application/vnd.ms-xpsdocument, application/xaml+xml, */*
2.使用扩展名
丧失了同一url多种展现的方式,但现在这种在实际环境中是使用最多的.因为更加符合程序员的审美观.
比如/user.json /user.xls /user.xml
使用参数 现在很多open API是使用这种方式,比如淘宝
但是对于不同浏览器可能accept-header并不是特别统一 因此许多实现选择了2 3两种方案
我们在Spring中采用上述两种方案
首先配置内容协商器
代码
@Bean public ViewResolver contentNegotiatingViewResolver( ContentNegotiationManager manager) { // Define the view resolvers ViewResolver beanNameViewResolver = new BeanNameViewResolver(); List<ViewResolver> resolvers = Lists.newArrayList(beanNameViewResolver); ContentNegotiatingViewResolver resolver = new ContentNegotiatingViewResolver(); resolver.setViewResolvers(resolvers); resolver.setContentNegotiationManager(manager); return resolver; } @Override public void configureContentNegotiation(ContentNegotiationConfigurer configurer) { configurer.favorPathExtension(true) .useJaf(false) .favorParameter(true) .parameterName("format") .ignoreAcceptHeader(true) .defaultContentType(MediaType.APPLICATION_JSON) .mediaType("json", MediaType.APPLICATION_JSON) .mediaType("xls", EXCEL_MEDIA_TYPE); }创建对应的转换器
private HttpMessageConverter<Object> createExcelHttpMessageConverter() { ExcelHttpMessageConverter excelHttpMessageConverter = new ExcelHttpMessageConverter(); return excelHttpMessageConverter; }直接使用easy-poi导出数据
/* * Copyright (c) 2017. Lorem ipsum dolor sit amet, consectetur adipiscing elit. * Morbi non lorem porttitor neque feugiat blandit. Ut vitae ipsum eget quam lacinia accumsan. * Etiam sed turpis ac ipsum condimentum fringilla. Maecenas magna. * Proin dapibus sapien vel ante. Aliquam erat volutpat. Pellentesque sagittis ligula eget metus. * Vestibulum commodo. Ut rhoncus gravida arcu. */ package com.f6car.base.web.converter; import cn.afterturn.easypoi.excel.ExcelExportUtil; import com.f6car.base.common.Result; import com.f6car.base.core.ExcelExport; import com.f6car.base.core.ExcelExportParam; import com.github.pagehelper.PageInfo; import com.google.common.collect.Lists; import org.apache.poi.ss.usermodel.Workbook; import org.springframework.http.HttpHeaders; import org.springframework.http.HttpInputMessage; import org.springframework.http.HttpOutputMessage; import org.springframework.http.MediaType; import org.springframework.http.converter.AbstractHttpMessageConverter; import org.springframework.http.converter.GenericHttpMessageConverter; import org.springframework.http.converter.HttpMessageNotReadableException; import org.springframework.http.converter.HttpMessageNotWritableException; import java.io.IOException; import java.lang.reflect.Type; import java.net.URLEncoder; import java.util.Collection; import java.util.Collections; import java.util.Map; import static com.f6car.base.core.F6Static.getExcelExportParam; /** * @author qixiaobo */ public class ExcelHttpMessageConverter extends AbstractHttpMessageConverter<Object> implements GenericHttpMessageConverter<Object> { public static final MediaType EXCEL_MEDIA_TYPE = new MediaType("application", "vnd.ms-excel"); public ExcelHttpMessageConverter() { super(EXCEL_MEDIA_TYPE); } @Override protected boolean supports(Class<?> clazz) { return false; } @Override protected Object readInternal(Class<?> clazz, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException { return null; } @Override protected void writeInternal(Object o, HttpOutputMessage outputMessage) throws IOException, HttpMessageNotWritableException { HttpHeaders headers = outputMessage.getHeaders(); Collection data = getActualData((Result) o); ExcelExportParam excelExportParam = getExcelExportParam(); Workbook workbook; switch (excelExportParam.getExcelExport()) { case NormalExcel: workbook = ExcelExportUtil.exportExcel( excelExportParam.getExportParams(), (Class<?>) excelExportParam.getClazz(), (Collection<?>) data); break; case MapExcel: workbook = ExcelExportUtil.exportExcel( excelExportParam.getExportParams(), excelExportParam.getExcelExportEntities(), (Collection<? extends Map<?, ?>>) data); break; case BigExcel: case MapExcelGraph: case PDFTemplate: case TemplateExcel: case TemplateWord: default: throw new RuntimeException(); } if (workbook != null) { if (excelExportParam.getFileName() != null) { String codedFileName = URLEncoder.encode(excelExportParam.getFileName(), "UTF8"); headers.setContentDispositionFormData("attachment", codedFileName); } workbook.write(outputMessage.getBody()); } } private Collection getActualData(Result r) { if (r != null && r.getData() != null) { Object data = r.getData(); if (data instanceof PageInfo) { return ((PageInfo) data).getList(); } else if (!(data instanceof Collection)) { data = Lists.newArrayList(data); } else { return (Collection) data; } } return Collections.emptyList(); } @Override public boolean canRead(Type type, Class<?> contextClass, MediaType mediaType) { //不支持excel return false; } @Override public Object read(Type type, Class<?> contextClass, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException { return null; } @Override public boolean canWrite(Type type, Class<?> clazz, MediaType mediaType) { return super.canWrite(mediaType) && clazz == Result.class && support(); } private boolean support() { ExcelExportParam param = getExcelExportParam(); if (param == null || param.getExcelExport() == null || param.getExportParams() == null) { return false; } if (param.getExcelExport() == ExcelExport.NormalExcel) { return true; } else { logger.warn(param.getExcelExport() + " not supprot now!"); return false; } } @Override public void write(Object o, Type type, MediaType contentType, HttpOutputMessage outputMessage) throws IOException, HttpMessageNotWritableException { super.write(o, contentType, outputMessage); } }暂时只是针对导出 因此在使用的时候如下
@GetMapping @ApiOperation(value = "获取实体列表", notes = "") public Result list(S so) { PageHelper.startPage(so.getCurrentPage(), so.getPageSize()); List<V> list = service.findAll(); PageInfo pageInfo = new PageInfo(list); excelExportParam(); return ResultGenerator.genSuccessResult(pageInfo); } protected void excelExportParam() { ExportParams ep = new ExportParams(null, "数据"); ExcelExportParam<V> param = new ExcelExportParam<>(); param.setClazz(voClazz); param.setExcelExport(ExcelExport.NormalExcel); param.setExportParams(ep); param.setFileName("文件.xls"); F6Static.setExcelExportParam(param); }当我们访问时如下
http://127.0.0.1:8079/zeus/user
{ "code": 200, "data": { "endRow": 10, "firstPage": 1, "hasNextPage": true, "hasPreviousPage": false, "isFirstPage": true, "isLastPage": false, "lastPage": 8, "list": [ { "cellPhone": "13857445502", "idEmployee": 24201883434352650, "idOwnOrg": 23993199378825296, "idRole": 88, "idWxbStation": "332", "idWxbUser": "207", "isAdmin": 1, "isDel": 0, "isGuideOpen": 0, "limitMac": 0, "openid": "", "password": "96e79218965eb72c92a549dd5a330112", "pkId": 23993199378825296, "username": "lingweiqiche" }, { "cellPhone": "", "idEmployee": 0, "idOwnOrg": 9999, "idRole": 4, "idWxbStation": "", "idWxbUser": "", "isAdmin": 0, "isDel": 0, "isGuideOpen": 0, "limitMac": 0, "openid": "", "password": "96e79218965eb72c92a549dd5a330112", "pkId": 24201883434356532, "username": "007" }, { "cellPhone": "15715139000", "idEmployee": 24351585207523460, "idOwnOrg": 24201883434357600, "idRole": 89, "idWxbStation": "540", "idWxbUser": "298", "isAdmin": 1, "isDel": 0, "isGuideOpen": 0, "limitMac": 0, "openid": "", "password": "96e79218965eb72c92a549dd5a330112", "pkId": 24201883434357600, "username": "15715139000" }, { "cellPhone": "", "idEmployee": 0, "idOwnOrg": 24201883434357600, "idRole": 216, "idWxbStation": "", "idWxbUser": "", "isAdmin": 0, "isDel": 0, "isGuideOpen": 0, "limitMac": 0, "openid": "", "password": "96e79218965eb72c92a549dd5a330112", "pkId": 24201883434357920, "username": "sunlingli" }, { "cellPhone": "", "idEmployee": 24351585207425676, "idOwnOrg": 24201883434359384, "idRole": 90, "idWxbStation": "348", "idWxbUser": "227", "isAdmin": 1, "isDel": 0, "isGuideOpen": 0, "limitMac": 0, "openid": "opzUDs_v13WE500kxYMj6Xg_gFeE", "password": "96e79218965eb72c92a549dd5a330112", "pkId": 24201883434359388, "username": "15952920979" }, { "cellPhone": "", "idEmployee": 0, "idOwnOrg": 24201883434359790, "idRole": 91, "idWxbStation": "315", "idWxbUser": "175", "isAdmin": 1, "isDel": 0, "isGuideOpen": 0, "limitMac": 0, "openid": "", "password": "96e79218965eb72c92a549dd5a330112", "pkId": 24201883434359790, "username": "13809056211" }, { "cellPhone": "18903885585", "idEmployee": 24201883434366164, "idOwnOrg": 24201883434359890, "idRole": 92, "idWxbStation": "317", "idWxbUser": "178", "isAdmin": 1, "isDel": 0, "isGuideOpen": 0, "limitMac": 0, "openid": "", "password": "96e79218965eb72c92a549dd5a330112", "pkId": 24201883434359892, "username": "18903885585" }, { "cellPhone": "", "idEmployee": 24351585207425668, "idOwnOrg": 24201883434359924, "idRole": 93, "idWxbStation": "318", "idWxbUser": "179", "isAdmin": 1, "isDel": 0, "isGuideOpen": 0, "limitMac": 0, "openid": "", "password": "96e79218965eb72c92a549dd5a330112", "pkId": 24201883434359930, "username": "13372299595" }, { "cellPhone": "", "idEmployee": 0, "idOwnOrg": 24201883434360052, "idRole": 94, "idWxbStation": "321", "idWxbUser": "188", "isAdmin": 1, "isDel": 0, "isGuideOpen": 0, "limitMac": 0, "openid": "", "password": "96e79218965eb72c92a549dd5a330112", "pkId": 24201883434360052, "username": "15221250005" }, { "cellPhone": "", "idEmployee": 0, "idOwnOrg": 24201883434360070, "idRole": 95, "idWxbStation": "325", "idWxbUser": "198", "isAdmin": 1, "isDel": 0, "isGuideOpen": 0, "limitMac": 0, "openid": "", "password": "96e79218965eb72c92a549dd5a330112", "pkId": 24201883434360070, "username": "13837251167" } ], "navigateFirstPage": 1, "navigateLastPage": 8, "navigatePages": 8, "navigatepageNums": [ 1, 2, 3, 4, 5, 6, 7, 8 ], "nextPage": 2, "orderBy": "", "pageNum": 1, "pageSize": 10, "pages": 102, "prePage": 0, "size": 10, "startRow": 1, "total": 1012 }, "message": "SUCCESS" }当访问http://127.0.0.1:8079/zeus/user?format=xls 或者http://127.0.0.1:8079/zeus/user.xls
如下效果
由于这边的数据和查询有关 因此我们可以这样操作http://127.0.0.1:8079/zeus/user.xls?pageSize=1000 轻而易举实现了查询结果xls化！
总结
以上所述是小编给大家介绍的SpringBoot中的内容协商器图解，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对武林网网站的支持！