'+'(加号)未使用String url使用RestTemplate编码,但解释为''(空格)

Question

我们正在从Java 8迁移到Java 11,因此,从Spring Boot 1.5.6迁移到2.1.2.我们注意到,当使用RestTemplate时,'+'符号不再编码为'%2B'(由SPR-14828更改).这没关系,因为RFC3986没有将'+'列为保留字符,但在Spring Boot端点接收时它仍被解释为''(空格).

我们有一个搜索查询,可以将可选的时间戳作为查询参数.查询看起来像http://example.com/search?beforeTimestamp=2019-01-21T14:56:50%2B00:00.

我们无法弄清楚如何发送编码加号,而不进行双重编码.查询参数2019-01-21T14:56:50+00:00将被解释为2019-01-21T14:56:50 00:00.如果我们要对参数self(2019-01-21T14:56:50%2B00:00)进行编码,那么它将被接收并解释为2019-01-21T14:56:50%252B00:00.

另一个约束是,我们希望在设置restTemplate时将基本URL设置在别处,而不是在执行查询的位置.

或者,有没有办法强制"+"不被端点解释为''？

我写了一个简短的例子,演示了一些实现更严格编码的方法,其缺点是作为评论解释:

package com.example.clientandserver;

import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.util.DefaultUriBuilderFactory;
import org.springframework.web.util.UriComponentsBuilder;
import org.springframework.web.util.UriUtils;

import java.nio.charset.StandardCharsets;
import java.util.HashMap;
import java.util.Map;

@SpringBootApplication
@RestController
public class ClientAndServerApp implements CommandLineRunner {

    public static void main(String[] args) {
        SpringApplication.run(ClientAndServerApp.class, args);
    }

    @Override
    public void run(String... args) {
        String beforeTimestamp = "2019-01-21T14:56:50+00:00";

        // Previously - base url and raw params (encoded automatically). This worked in the earlier version of Spring Boot
        {
            RestTemplate restTemplate = new RestTemplateBuilder().rootUri("http://localhost:8080").build();
            UriComponentsBuilder b = UriComponentsBuilder.fromPath("/search");
            if (beforeTimestamp != null) {
                b.queryParam("beforeTimestamp", beforeTimestamp);
            }
            restTemplate.getForEntity(b.toUriString(), Object.class);
            // Received: 2019-01-21T14:56:50 00:00
            //       Plus sign missing here ^
        }

        // Option 1 - no base url and encoding the param ourselves.
        {
            RestTemplate restTemplate = new RestTemplate();
            UriComponentsBuilder b = UriComponentsBuilder.fromHttpUrl("http://localhost:8080/search");
            if (beforeTimestamp != null) {
                b.queryParam("beforeTimestamp", UriUtils.encode(beforeTimestamp, StandardCharsets.UTF_8));
            }
            restTemplate.getForEntity(b.build(true).toUri(), Object.class).getBody();
            // Received: 2019-01-21T14:56:50+00:00
        }

        // Option 2 - with base url, but templated, so query parameter is not optional.
        {
            RestTemplate restTemplate = new RestTemplateBuilder().rootUri("http://localhost:8080").uriTemplateHandler(new DefaultUriBuilderFactory()).build();
            Map<String, String> params = new HashMap<>();
            params.put("beforeTimestamp", beforeTimestamp);
            restTemplate.getForEntity("/search?beforeTimestamp={beforeTimestamp}", Object.class, params);
            // Received: 2019-01-21T14:56:50+00:00
        }
    }

    @GetMapping("/search")
    public void search(@RequestParam String beforeTimestamp) {
        System.out.println("Received: " + beforeTimestamp);
    }
}

Answer 1

我们意识到可以在编码完成后在拦截器中修改URL。因此，一种解决方案是使用拦截器，该拦截器对查询参数中的加号进行编码。

RestTemplate restTemplate = new RestTemplateBuilder()
        .rootUri("http://localhost:8080")
        .interceptors(new PlusEncoderInterceptor())
        .build();

一个简短的例子：

public class PlusEncoderInterceptor implements ClientHttpRequestInterceptor {

    @Override
    public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException {
        return execution.execute(new HttpRequestWrapper(request) {
            @Override
            public URI getURI() {
                URI u = super.getURI();
                String strictlyEscapedQuery = StringUtils.replace(u.getRawQuery(), "+", "%2B");
                return UriComponentsBuilder.fromUri(u)
                        .replaceQuery(strictlyEscapedQuery)
                        .build(true).toUri();
            }
        }, body);
    }
}