SpringBoot中的内容协商器图解
作者：波波维奇
本文通过图文解说加代码的形式给大家介绍了SpringBoot中的内容协商器知识，需要的朋友参考下吧
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脚本之家网站的支持！