SpringBoot中的内容协商器图解
发布时间：2020-12-14 20:56:00 所属栏目：Java 来源：网络整理
导读：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RestContr
|
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/xml;q=0.9,*/*;q=0.8
IE8:
Accept:image/gif,image/jpeg,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,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,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,"pkId": 24201883434356532,"username": "007"
},{
"cellPhone": "15715139000","idEmployee": 24351585207523460,"idOwnOrg": 24201883434357600,"idRole": 89,"idWxbStation": "540","idWxbUser": "298","pkId": 24201883434357600,"username": "15715139000"
},"idRole": 216,"pkId": 24201883434357920,"username": "sunlingli"
},"idEmployee": 24351585207425676,"idOwnOrg": 24201883434359384,"idRole": 90,"idWxbStation": "348","idWxbUser": "227","openid": "opzUDs_v13WE500kxYMj6Xg_gFeE","pkId": 24201883434359388,"username": "15952920979"
},"idOwnOrg": 24201883434359790,"idRole": 91,"idWxbStation": "315","idWxbUser": "175","pkId": 24201883434359790,"username": "13809056211"
},{
"cellPhone": "18903885585","idEmployee": 24201883434366164,"idOwnOrg": 24201883434359890,"idRole": 92,"idWxbStation": "317","idWxbUser": "178","pkId": 24201883434359892,"username": "18903885585"
},"idEmployee": 24351585207425668,"idOwnOrg": 24201883434359924,"idRole": 93,"idWxbStation": "318","idWxbUser": "179","pkId": 24201883434359930,"username": "13372299595"
},"idOwnOrg": 24201883434360052,"idRole": 94,"idWxbStation": "321","idWxbUser": "188","pkId": 24201883434360052,"username": "15221250005"
},"idOwnOrg": 24201883434360070,"idRole": 95,"idWxbStation": "325","idWxbUser": "198","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编程小技巧网站的支持！ （编辑：李大同） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |
相关内容