Flutter网络请求的3种简单实现方法

概述：

app几乎都离不开与服务器的交互，本文主要讲解了flutter网络请求三种方式 flutter自带的httpclient、 第三方库http 和 第三方库dio  的简单实现 get 和 post请求，本文是笔者学习flutter网络模块知识总结，若有问题还望不腻赐教。

一.系统自带httpclient

1.使用中温馨提示

1.1.导入库

import 'dart:io'; // 网络请求
import 'dart:convert'; // 数据解析

1.2.uri的多种初始化方式

// 方法1
uri uri = uri(scheme: 'https', host: 'app.xxx.com', path: homenovicelisturl);
// 方法2
uri uri = uri.https('app.xxx.com', homenovicelisturl);
// uri方法3
uri uri = uri.parse(baseurl + homenovicelisturl);

2.简单使用

2.1.get请求

// 1.1 httpclient - get 

void loaddata_sys_get() async {
print('------loaddata_sys_get--------');

var httpclient = new httpclient();
var params = map<string, string>();

// uri方法1
uri uri =
 uri(scheme: 'https', host: 'app.xxx.com', path: homenovicelisturl);

// uri方法2
// uri uri = uri.https(
// 'app.xxx.com', homenovicelisturl);

// uri方法3
// uri uri = uri.parse(baseurl + homenovicelisturl);

var request = await httpclient.geturl(uri);

var headers = map<string, string>();
headers['loginsource'] = 'ios';
headers['useversion'] = '3.1.0';
headers['isencoded'] = '1';
headers['bundleid'] = 'com.xxx.xxx';

request.headers.add("loginsource", "ios");
request.headers.add("useversion", "3.1.0");
request.headers.add("isencoded", "1");
request.headers.add("bundleid", "com.xxx.xxx");

var response = await request.close();
var responsebody = await response.transform(utf8decoder()).join();

if (response.statuscode == httpstatus.ok) {
 print('请求头：${response.headers}');

 print('111请求成功代发数据为:\n $responsebody');
 print('--------------');
 map data = jsondecode(responsebody);
 print('222请求成功代发数据为:\n $data');
} else {
 print('\n\n\n11111==请求失败${response.statuscode}');
}
}

2.2.post请求

注意点：请求参数需要编码后放在request中

void loaddata_sys_post() async {
print('------loaddata_sys_post--------');

httpclient httpclient = new httpclient();

// queryparameters get请求的查询参数(适用于get请求？？？是吗？？？)
// uri uri = uri(
// scheme: "https", host: "app.xxx.com", path: homeregularlisturl);
// httpclientrequest request = await httpclient.posturl(uri);

var url = baseurl + homeregularlisturl;
httpclientrequest request = await httpclient.posturl(uri.parse(url));

// 设置请求头
request.headers.set("loginsource", "ios");
request.headers.set("useversion", "3.1.0");
request.headers.set("isencoded", "1");
request.headers.set("bundleid", "com.xxx.xxx");
// content-type大小写都ok
request.headers.set('content-type', 'application/json');

/// 添加请求体
/// https://*.com/questions/50278258/http-post-with-json-on-body-flutter-dart/50295533
map jsonmap = {'currentpage': '1'};
request.add(utf8.encode(json.encode(jsonmap)));

httpclientresponse response = await request.close();
string responsebody = await response.transform(utf8.decoder).join();
if (response.statuscode == httpstatus.ok) {
 print('请求成功');
 print(response.headers);
 print(responsebody);
}
}

二.请求第三方库 http

1.使用中温馨提示

1.1.添加依赖

dependencies:
 http: ^0.12.0 #latest version

1.2.导入库

import 'package:http/http.dart' as http; //导入前需要配置

2.简单使用

2.1. get请求

2.2.1. http - get1

 void loaddata_http_get() async {
 print('------loaddata_http_get--------');

 var client = http.client();

 var uri = uri.parse(baseurl + homenovicelisturl);

 http.response response = await client.get(uri);

 if (response.statuscode == httpstatus.ok) {
 print(response.body);
 } else {
 print('请求失败 code 码为${response.statuscode}');
 }
 }

2.2. http - get简便方法（链式编程）

void loaddata_http_get_convenience() async {
 print('------简便方法loaddata_http_get_convenience--------');

 var uri = uri.parse(baseurl + homenovicelisturl);

 http.client().get(uri).then((http.response response) {
 if (response.statuscode == httpstatus.ok) {
 print(response.body);
 } else {
 print('请求失败 code 码为${response.statuscode}');
 }
 });
 }

2.2. post请求

2.2.1.  http - post

 void loaddata_http_post() async {
 print('------ loaddata_http_post --------');

 var headers = map<string, string>();
 headers["loginsource"] = "ios";
 headers["useversion"] = "3.1.0";
 headers["isencoded"] = "1";
 headers["bundleid"] = "com.xxx.xxx";
 headers["loginsource"] = "ios";
 headers["content\-type"] = "application/json";

 map params = {'currentpage': '1'};
 // 嵌套两层都可以，但是具体哪个好还有待确认？？？？
 var jsonparams = utf8.encode(json.encode(params));
 // var jsonparams = json.encode(params);

 var httpclient = http.client();

 var uri = uri.parse(baseurl + homenovicelisturl);

 http.response response =
 await httpclient.post(uri, body: jsonparams, headers: headers);

 if (response.statuscode == httpstatus.ok) {
 print(response.body);
 } else {
 print('请求失败 code 码���${response.statuscode}');
 }
 }

2.2.2. http - post简便方法（链式编程）

 void loaddata_http_post_convenience() async {
 print('------ loaddata_http_post --------');

 var headers = map<string, string>();
 headers["loginsource"] = "ios";
 headers["useversion"] = "3.1.0";
 headers["isencoded"] = "1";
 headers["bundleid"] = "com.xxx.xxx";
 headers["loginsource"] = "ios";
 headers["content\-type"] = "application/json";

 map params = {'currentpage': '1'};
 // 嵌套两层都可以，但是具体哪个好还有待确认？？？？
 var jsonparams = utf8.encode(json.encode(params));
 // var jsonparams = json.encode(params);

 var httpclient = http.client();

 var url = baseurl + homeregularlisturl;

 httpclient.post(url, body: jsonparams, headers: headers).then((response) {
 print("response status: ${response.statuscode}");
 print("response body: ${response.body}");
 }).whencomplete(httpclient.close);
 }

三.请求第三方库 dio

1.使用中温馨提示

1.1.添加依赖

dependencies:
 dio: ^2.0.11 #latest version

1.2.导入库

import 'package:dio/dio.dart';

2.简单使用

2.1. get请求

注意：dio的get请求（baseurl都是在dio.option.baseurl设置的） 请求头可以在dio.option上设置，也可以在新建的option上设置,新建option是可选的

void loaddata_dio_get() async {
 var headers = map<string, string>();
 headers['loginsource'] = 'ios';
 headers['useversion'] = '3.1.0';
 headers['isencoded'] = '1';
 headers['bundleid'] = 'com.xxx.xxx';
 headers['content-type'] = 'application/json';

 dio dio = dio();
 dio.options.headers.addall(headers);
 dio.options.baseurl = baseurl;

 response response = await dio.get(homenovicelisturl);

 if (response.statuscode == httpstatus.ok) {
 print(response.headers);
 print(response.data);
 }
 }

2.2. post请求

注意：

dio.options.method设置是无效
dio dio = dio();
dio.options.method = 'post';

办法：
新建一个options对象，然后在发起请求的时候进行设置：
options option = options(method:'post');
response response = await dio.request(homeregularlisturl,data:{"currentpage": "1"}, options: option);

2.2.1. dio - 方式一（baseurl都是在dio.option.baseurl设置的）

注意：直接在 dio.options设置除methods以外的 请求头参数

void loaddata_dio_dioofoptionssetting() async {
 debugprint(
 ' \n post请求 ======================= 开始请求 =======================\n');
 var headers = map<string, string>();
 headers['loginsource'] = 'ios';
 headers['useversion'] = '3.1.0';
 headers['isencoded'] = '1';
 headers['bundleid'] = 'com.xxx.xxx';
 headers['content-type'] = 'application/json';

 dio dio = dio();
 dio.options.baseurl = baseurl;
 dio.options.connecttimeout = 60000;
 dio.options.receivetimeout = 60000;
 dio.options.headers.addall(headers);
 dio.options.method = 'post';

 options option = options(method: 'post');
 // response response = await dio.request(homeregularlisturl,
 // data: {"currentpage": "1"}, options: option);

 response response = await dio.post(homeregularlisturl,
 data: {"currentpage": "1"}, options: option);

 if (response.statuscode == httpstatus.ok) {
 debugprint('请求参数： ${response.request.queryparameters}');
 debugprint(
  '-------------------请求成功,请求结果如下:-----------------\n \n===请求求url: ${response.request.uri.tostring()} \n \n===请求 ���: \n${response.headers} \n \n===请求结果: \n${response.data}\n');
 debugprint('-------------------请求成功,请求结果打印完毕----------------');
 } else {
 print('请求失败');
 }
 }

2.2.2. dio - 方式二（baseurl都是在dio.option.baseurl设置的）

注意：在新建的option上设置请求头参数

void loaddata_dio_newoptionsetting() async {
 debugprint(' \n======================= 开始请求 =======================\n');
 var headers = map<string, string>();
 headers['loginsource'] = 'ios';
 headers['useversion'] = '3.1.0';
 headers['isencoded'] = '1';
 headers['bundleid'] = 'com.xxx.xxx';
 headers['content-type'] = 'application/json';

 options option = options(method: 'post');
 option.connecttimeout = 60000;
 option.receivetimeout = 60000;
 option.headers.addall(headers);

 dio dio = dio();
 dio.options.baseurl = baseurl;

 response response = await dio.post(homeregularlisturl,
 data: {"currentpage": 1}, options: option);
 // response response = await dio.request(homeregularlisturl,
 // data: {"currentpage": 1}, options: option);

 if (response.statuscode == httpstatus.ok) {
 debugprint('请求参数： ${response.request.queryparameters}');
 debugprint(
  '-------------------请求成功,请求结果如下:-----------------\n \n===请求url: ${response.request.uri.tostring()} \n \n===请求 头: \n${response.headers} \n \n===请求结果: \n${response.data}\n');
 debugprint('-------------------请求成功,请求结果打印完毕----------------');
 } else {
 print('请求失败');
 }
 }

总结

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