SpringBoot中的内容协商器图解
程序员文章站
2024-02-26 15:04:58
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...
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
{
"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 或者
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
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