JAVA-000

返回Week_02主页

作业要求

第四节课作业实践 2、写一段代码，使用 HttpClient 或 OkHttp 访问 http://localhost:8801 ，代码提交到Github。

简述

使用之前练习的一个 咖啡 Rest API 小程序，同时参考如下链接，写了一个简单的 HttpClient小程序，演练如何使用 HttpClient 访问咖啡Rest API：

• Java HTTP Client
• Introduction to the Java HTTP Client
• Examples and Recipes
• Java HttpClient API Tutorial with Examples

讲解

1. 首先要运行 course4-question2/complex-controller 这个咖啡系统。
2. 然后运行 course4-question2/httpclient-demo 示例工程，其中 OrderClient.java 演示了HttpClient的基本用法。

getCoffeeMenu

Source Code:

public void getCoffeeMenu() throws IOException, InterruptedException {
    System.out.println("\nGet coffee menu");
    String uri = "http://localhost:8801/coffee/";
    HttpClient client = HttpClient.newHttpClient();
    HttpRequest request = HttpRequest.newBuilder()
            .uri(URI.create(uri))
            .build();
    HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
    System.out.println("Response status code: " + response.statusCode());
    System.out.println("Response body: " + response.body());
}

给 http://localhost:8801/coffee/ 发送一个GET请求。

getCoffeeByName

Source Code:

public void getCoffeeByName(String name) throws IOException, InterruptedException {
    System.out.println("\nGet coffee by name: " + name);
    String uri = "http://localhost:8801/coffee/?name=" + name;
    HttpClient client = HttpClient.newHttpClient();
    HttpRequest request = HttpRequest.newBuilder()
            .uri(URI.create(uri))
            .build();
    HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
    System.out.println("Response status code: " + response.statusCode());
    System.out.println("Response body: " + response.body());
}

给 http://localhost:8801/coffee/?name=name 发送一个GET请求。

getCoffeeById

Source Code:

public void getCoffeeById(int id) throws IOException, InterruptedException {
    System.out.println("\nGet coffee by id: " + id);
    String uri = "http://localhost:8801/coffee/" + id;
    HttpClient client = HttpClient.newHttpClient();
    HttpRequest request = HttpRequest.newBuilder()
            .uri(URI.create(uri))
            .header("Accept", "application/json;charset=UTF-8")
            .build();
    HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
    System.out.println("Response status code: " + response.statusCode());
    System.out.println("Response body: " + response.body());
}

给 http://localhost:8801/coffee/id 发送一个GET请求，同时使用Header:

• Accept: application/json;charset=UTF-8

createOrder

Source Code:

public void createOrder(Order order) throws IOException {
    System.out.println("\nCreate an order");
    String uri = "http://localhost:8801/order/";
    ObjectMapper objectMapper = new ObjectMapper();
    String json = objectMapper.writeValueAsString(order);

    HttpClient client = HttpClient.newHttpClient();
    HttpRequest request = HttpRequest.newBuilder()
            .uri(URI.create(uri))
            .header("Content-Type", "application/json")
            .header("Accept", "application/json;charset=UTF-8")
            .POST(HttpRequest.BodyPublishers.ofString(json))
            .build();

    CompletableFuture<HttpResponse<String>> completableFuture =
            client.sendAsync(request, HttpResponse.BodyHandlers.ofString());
    completableFuture.thenApplyAsync(HttpResponse::headers)
            .thenAcceptAsync(System.out::println);
    HttpResponse<String> response = completableFuture.join();
    System.out.println("Response status code: " + response.statusCode());
    System.out.println("Response body: " + response.body());
}

给 http://localhost:8801/order/ 发送一个POST请求，同时使用Header:

• Content-Type”, “application/json
• Accept: application/json;charset=UTF-8

程序运行结果

Get coffee menu
Response status code: 200
Response body: [{"id":1,"createTime":"2020-10-28T14:27:28.993+00:00","updateTime":"2020-10-28T14:27:28.993+00:00","name":"espresso","price":{"amountMinor":2000,"amountMajorInt":20,"amountMajorLong":20,"amountMinorInt":2000,"minorPart":0,"positiveOrZero":true,"amountMinorLong":2000,"negativeOrZero":false,"amountMajor":20,"currencyUnit":{"code":"CNY","numericCode":156,"decimalPlaces":2,"pseudoCurrency":false,"numeric3Code":"156","countryCodes":["CN"],"symbol":"CN¥"},"amount":20.00,"scale":2,"negative":false,"zero":false,"positive":true}},{"id":2,"createTime":"2020-10-28T14:27:29.014+00:00","updateTime":"2020-10-28T14:27:29.014+00:00","name":"latte","price":{"amountMinor":2500,"amountMajorInt":25,"amountMajorLong":25,"amountMinorInt":2500,"minorPart":0,"positiveOrZero":true,"amountMinorLong":2500,"negativeOrZero":false,"amountMajor":25,"currencyUnit":{"code":"CNY","numericCode":156,"decimalPlaces":2,"pseudoCurrency":false,"numeric3Code":"156","countryCodes":["CN"],"symbol":"CN¥"},"amount":25.00,"scale":2,"negative":false,"zero":false,"positive":true}},{"id":3,"createTime":"2020-10-28T14:27:29.015+00:00","updateTime":"2020-10-28T14:27:29.015+00:00","name":"capuccino","price":{"amountMinor":2500,"amountMajorInt":25,"amountMajorLong":25,"amountMinorInt":2500,"minorPart":0,"positiveOrZero":true,"amountMinorLong":2500,"negativeOrZero":false,"amountMajor":25,"currencyUnit":{"code":"CNY","numericCode":156,"decimalPlaces":2,"pseudoCurrency":false,"numeric3Code":"156","countryCodes":["CN"],"symbol":"CN¥"},"amount":25.00,"scale":2,"negative":false,"zero":false,"positive":true}},{"id":4,"createTime":"2020-10-28T14:27:29.015+00:00","updateTime":"2020-10-28T14:27:29.015+00:00","name":"mocha","price":{"amountMinor":3000,"amountMajorInt":30,"amountMajorLong":30,"amountMinorInt":3000,"minorPart":0,"positiveOrZero":true,"amountMinorLong":3000,"negativeOrZero":false,"amountMajor":30,"currencyUnit":{"code":"CNY","numericCode":156,"decimalPlaces":2,"pseudoCurrency":false,"numeric3Code":"156","countryCodes":["CN"],"symbol":"CN¥"},"amount":30.00,"scale":2,"negative":false,"zero":false,"positive":true}},{"id":5,"createTime":"2020-10-28T14:27:29.016+00:00","updateTime":"2020-10-28T14:27:29.016+00:00","name":"macchiato","price":{"amountMinor":3000,"amountMajorInt":30,"amountMajorLong":30,"amountMinorInt":3000,"minorPart":0,"positiveOrZero":true,"amountMinorLong":3000,"negativeOrZero":false,"amountMajor":30,"currencyUnit":{"code":"CNY","numericCode":156,"decimalPlaces":2,"pseudoCurrency":false,"numeric3Code":"156","countryCodes":["CN"],"symbol":"CN¥"},"amount":30.00,"scale":2,"negative":false,"zero":false,"positive":true}}]

Get coffee by id: 2
Response status code: 200
Response body: {"id":2,"createTime":"2020-10-28T14:27:29.014+00:00","updateTime":"2020-10-28T14:27:29.014+00:00","name":"latte","price":{"amountMinor":2500,"amountMajorInt":25,"amountMajorLong":25,"amountMinorInt":2500,"minorPart":0,"positiveOrZero":true,"amountMinorLong":2500,"negativeOrZero":false,"amountMajor":25,"currencyUnit":{"code":"CNY","numericCode":156,"decimalPlaces":2,"pseudoCurrency":false,"numeric3Code":"156","countryCodes":["CN"],"symbol":"CN¥"},"amount":25.00,"scale":2,"negative":false,"zero":false,"positive":true}}

Get coffee by name: latte
Response status code: 200
Response body: {"id":2,"createTime":"2020-10-28T14:27:29.014+00:00","updateTime":"2020-10-28T14:27:29.014+00:00","name":"latte","price":{"amountMinor":2500,"amountMajorInt":25,"amountMajorLong":25,"amountMinorInt":2500,"minorPart":0,"positiveOrZero":true,"amountMinorLong":2500,"negativeOrZero":false,"amountMajor":25,"currencyUnit":{"code":"CNY","numericCode":156,"decimalPlaces":2,"pseudoCurrency":false,"numeric3Code":"156","countryCodes":["CN"],"symbol":"CN¥"},"amount":25.00,"scale":2,"negative":false,"zero":false,"positive":true}}

Create an order
Response status code: 201
Response body: {"id":2,"createTime":"2020-10-28T14:29:45.020+00:00","updateTime":"2020-10-28T14:29:45.020+00:00","customer":"Feng Du","items":[{"id":2,"createTime":"2020-10-28T14:27:29.014+00:00","updateTime":"2020-10-28T14:27:29.014+00:00","name":"latte","price":{"amountMinor":2500,"amountMajorInt":25,"amountMajorLong":25,"amountMinorInt":2500,"minorPart":0,"positiveOrZero":true,"amountMinorLong":2500,"negativeOrZero":false,"amountMajor":25,"currencyUnit":{"code":"CNY","numericCode":156,"decimalPlaces":2,"pseudoCurrency":false,"numeric3Code":"156","countryCodes":["CN"],"symbol":"CN¥"},"amount":25.00,"scale":2,"negative":false,"zero":false,"positive":true}},{"id":4,"createTime":"2020-10-28T14:27:29.015+00:00","updateTime":"2020-10-28T14:27:29.015+00:00","name":"mocha","price":{"amountMinor":3000,"amountMajorInt":30,"amountMajorLong":30,"amountMinorInt":3000,"minorPart":0,"positiveOrZero":true,"amountMinorLong":3000,"negativeOrZero":false,"amountMajor":30,"currencyUnit":{"code":"CNY","numericCode":156,"decimalPlaces":2,"pseudoCurrency":false,"numeric3Code":"156","countryCodes":["CN"],"symbol":"CN¥"},"amount":30.00,"scale":2,"negative":false,"zero":false,"positive":true}}],"state":"INIT"}