日常问题随笔-RestTemplate发送Get请求通过body传参问题

问题出现

今天在对接其他部门的接口时，发现对方提供了一个GET请求，但是参数却要求通过body传递json格式的数据。这可难住我了，GET请求还能通过body传递参数吗？带着疑问，先试一下吧。我们项目用的RestTemplate，我想起了RestTemplate的exchange方法有个参数HttpEntity，会不会是这里可以传参数进去呢？迅速写了代码

public static String getForJson(String url, Map<String,Object> dataValue) {
    HttpHeaders httpHeaders = new HttpHeaders();
    httpHeaders.setContentType(MediaType.APPLICATION_JSON_UTF8);
    HttpEntity<String> httpEntity = new HttpEntity<>(JSON.toJSONString(dataValue),httpHeaders);
    return SpringContextUtil.getBean(RestTemplate.class).exchange(url, HttpMethod.GET,httpEntity,String.class).getBody();
}

结果

2020-06-18 17:08:37.544|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "GET /cross/appms-internal/v1/portal/app/config/search HTTP/1.1[\r][\n]"
2020-06-18 17:08:37.544|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "Accept: text/plain, application/json, application/*+json, */*[\r][\n]"
2020-06-18 17:08:37.544|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "Content-Type: application/json;charset=UTF-8[\r][\n]"
2020-06-18 17:08:37.544|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "Accept-Charset: big5, big5-hkscs, cesu-8, euc-jp, euc-kr, gb18030, gb2312, gbk, ibm-thai, ibm00858, ibm01140, ibm01141, ibm01142, ibm01143, ibm01144, ibm01145, ibm01146, ibm01147, ibm01148, ibm01149, ibm037, ibm1026, ibm1047, ibm273, ibm277, ibm278, ibm280, ibm284, ibm285, ibm290, ibm297, ibm420, ibm424, ibm437, ibm500, ibm775, ibm850, ibm852, ibm855, ibm857, ibm860, ibm861, ibm862, ibm863, ibm864, ibm865, ibm866, ibm868, ibm869, ibm870, ibm871, ibm918, iso-2022-cn, iso-2022-jp, iso-2022-jp-2, iso-2022-kr, iso-8859-1, iso-8859-13, iso-8859-15, iso-8859-2, iso-8859-3, iso-8859-4, iso-8859-5, iso-8859-6, iso-8859-7, iso-8859-8, iso-8859-9, jis_x0201, jis_x0212-1990, koi8-r, koi8-u, shift_jis, tis-620, us-ascii, utf-16, utf-16be, utf-16le, utf-32, utf-32be, utf-32le, utf-8, windows-1250, windows-1251, windows-1252, windows-1253, windows-1254, windows-1255, windows-1256, windows-1257, windows-1258, windows-31j, x-big5-hkscs-2001, x-big5-solaris, x-euc-jp-linux, x-euc-tw, x-eucjp-open, x-ibm1006, x-ibm1025, x-ibm1046, x-ibm1097, x-ibm1098, x-ibm1112, x-ibm1122, x-ibm1123, x-ibm1124, x-ibm1166, x-ibm1364, x-ibm1381, x-ibm1383, x-ibm300, x-ibm33722, x-ibm737, x-ibm833, x-ibm834, x-ibm856, x-ibm874, x-ibm875, x-ibm921, x-ibm922, x-ibm930, x-ibm933, x-ibm935, x-ibm937, x-ibm939, x-ibm942, x-ibm942c, x-ibm943, x-ibm943c, x-ibm948, x-ibm949, x-ibm949c, x-ibm950, x-ibm964, x-ibm970, x-iscii91, x-iso-2022-cn-cns, x-iso-2022-cn-gb, x-iso-8859-11, x-jis0208, x-jisautodetect, x-johab, x-macarabic, x-maccentraleurope, x-maccroatian, x-maccyrillic, x-macdingbat, x-macgreek, x-machebrew, x-maciceland, x-macroman, x-macromania, x-macsymbol, x-macthai, x-macturkish, x-macukraine, x-ms932_0213, x-ms950-hkscs, x-ms950-hkscs-xp, x-mswin-936, x-pck, x-sjis_0213, x-utf-16le-bom, x-utf-32be-bom, x-utf-32le-bom, x-windows-50220, x-windows-50221, x-windows-874, x-windows-949, x-windows-950, x-windows-iso2022jp[\r][\n]"
2020-06-18 17:08:37.547|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "Host: [\r][\n]"
2020-06-18 17:08:37.547|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "Connection: Keep-Alive[\r][\n]"
2020-06-18 17:08:37.547|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "User-Agent: Apache-HttpClient/4.5.10 (Java/1.8.0_201)[\r][\n]"
2020-06-18 17:08:37.547|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "Accept-Encoding: gzip,deflate[\r][\n]"
2020-06-18 17:08:37.547|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "[\r][\n]"
2020-06-18 17:08:37.734|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 << "HTTP/1.1 400 [\r][\n]"
2020-06-18 17:08:37.735|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 << "Server: nginx[\r][\n]"
2020-06-18 17:08:37.735|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 << "Date: Thu, 18 Jun 2020 09:08:36 GMT[\r][\n]"
2020-06-18 17:08:37.736|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 << "Content-Type: application/json;charset=UTF-8[\r][\n]"
2020-06-18 17:08:37.736|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 << "Transfer-Encoding: chunked[\r][\n]"
2020-06-18 17:08:37.736|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 << "Connection: keep-alive[\r][\n]"
2020-06-18 17:08:37.737|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 << "X-Application-Context: cross-gateway:test:8080[\r][\n]"
2020-06-18 17:08:37.737|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 << "Set-Cookie: Track_id=rBCB8F7rLxRhG2WIFf7OAg==; expires=Fri, 18-Jun-21 09:08:36 GMT; domain=test.cn; path=/[\r][\n]"
2020-06-18 17:08:37.737|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 << "[\r][\n]"
2020-06-18 17:08:37.738|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 << "2b[\r][\n]"
2020-06-18 17:08:37.738|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 << "{"code":4004,"message":"parameter invalid"}[\r][\n]"
2020-06-18 17:08:37.738|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 << "0[\r][\n]"
2020-06-18 17:08:37.739|DEBUG|http-nio-8090-exec-2|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 << "[\r][\n]"

通过日志可以看到请求失败了，对方接口返回了参数无效

{"code":4004,"message":"parameter invalid"}

解决问题

在HTTP1.1中GET请求已经可以在body里发送数据，但是既然用了RestTemplate，就要看一下RestTemplate是否提供了实现，这里我们用的httpclient，默认用的HttpComponentsClientHttpRequestFactory工厂，查看了HttpComponentsClientHttpRequestFactory的createHttpUriRequest方法，发现GET请求是HttpGet，HttpGet继承HttpRequestBase，HttpRequestBase是不支持传递body的。

protected HttpUriRequest createHttpUriRequest(HttpMethod httpMethod, URI uri) {
    switch (httpMethod) {
        case GET:
            return new HttpGet(uri);
        case HEAD:
            return new HttpHead(uri);
        case POST:
            return new HttpPost(uri);
        case PUT:
            return new HttpPut(uri);
        case PATCH:
            return new HttpPatch(uri);
        case DELETE:
            return new HttpDelete(uri);
        case OPTIONS:
            return new HttpOptions(uri);
        case TRACE:
            return new HttpTrace(uri);
        default:
            throw new IllegalArgumentException("Invalid HTTP method: " + httpMethod);
    }
}

查了资料发现HttpEntityEnclosingRequestBase是可以传递body的，那就自定义一个工厂继承HttpComponentsClientHttpRequestFactory，重写createHttpUriRequest方法，当发送的请求是GET请求时，创建自定义的继承HttpEntityEnclosingRequestBase的类，这样GET请求就可以传送body。

@Configuration
public class RestTemplateConfig {
    @Bean
    public RestTemplate restTemplate(ClientHttpRequestFactory clientHttpRequestFactory) {
        return new RestTemplate(clientHttpRequestFactory);
    }

    @Bean
    public ClientHttpRequestFactory httpRequestFactory(HttpClient httpClient) {

        return new HttpComponentsClientHttpRequestCRMFactory(httpClient);

    }

    @Bean
    public HttpClient httpClient() {
        Registry<ConnectionSocketFactory> registry = RegistryBuilder.<ConnectionSocketFactory>create()
                .register("http", PlainConnectionSocketFactory.getSocketFactory())
                .register("https", SSLConnectionSocketFactory.getSocketFactory())
                .build();
        PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager(registry);
        //设置整个连接池最大连接数 根据自己的场景决定
        connectionManager.setMaxTotal(200);
        //路由是对maxTotal的细分
        connectionManager.setDefaultMaxPerRoute(100);
        RequestConfig requestConfig = RequestConfig.custom()
                .setSocketTimeout(10000) //服务器返回数据(response)的时间，超过该时间抛出read timeout
                .setConnectTimeout(5000)//连接上服务器(握手成功)的时间，超出该时间抛出connect timeout
                .setConnectionRequestTimeout(1000)//从连接池中获取连接的超时时间，超过该时间未拿到可用连接，会抛出org.apache.http.conn.ConnectionPoolTimeoutException: Timeout waiting for connection from pool
                .build();
        return HttpClientBuilder.create()
                .setDefaultRequestConfig(requestConfig)
                .setConnectionManager(connectionManager)
                .build();
    }

    private static final class HttpComponentsClientHttpRequestCRMFactory extends HttpComponentsClientHttpRequestFactory {
        public HttpComponentsClientHttpRequestCRMFactory(HttpClient httpClient) {
            super(httpClient);
        }

        @Override
        protected HttpUriRequest createHttpUriRequest(HttpMethod httpMethod, URI uri) {
            if (httpMethod == HttpMethod.GET) {
                return new HttpGetRequestForBody(uri);
            }
            return super.createHttpUriRequest(httpMethod, uri);
        }
    }

    private static final class HttpGetRequestForBody extends HttpEntityEnclosingRequestBase {
        public HttpGetRequestForBody(final URI uri) {
            super.setURI(uri);
        }

        @Override
        public String getMethod() {
            return HttpMethod.GET.name();
        }
    }
}

测试结果

再次测试结果，发现调用正确返回

2020-06-18 17:10:28.403|DEBUG|http-nio-8090-exec-1|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "GET /cross/appms-internal/v1/portal/app/config/search HTTP/1.1[\r][\n]"
2020-06-18 17:10:28.404|DEBUG|http-nio-8090-exec-1|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "Accept: text/plain, application/json, application/*+json, */*[\r][\n]"
2020-06-18 17:10:28.404|DEBUG|http-nio-8090-exec-1|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "Content-Type: application/json;charset=UTF-8[\r][\n]"
2020-06-18 17:10:28.407|DEBUG|http-nio-8090-exec-1|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "Accept-Charset: big5, big5-hkscs, cesu-8, euc-jp, euc-kr, gb18030, gb2312, gbk, ibm-thai, ibm00858, ibm01140, ibm01141, ibm01142, ibm01143, ibm01144, ibm01145, ibm01146, ibm01147, ibm01148, ibm01149, ibm037, ibm1026, ibm1047, ibm273, ibm277, ibm278, ibm280, ibm284, ibm285, ibm290, ibm297, ibm420, ibm424, ibm437, ibm500, ibm775, ibm850, ibm852, ibm855, ibm857, ibm860, ibm861, ibm862, ibm863, ibm864, ibm865, ibm866, ibm868, ibm869, ibm870, ibm871, ibm918, iso-2022-cn, iso-2022-jp, iso-2022-jp-2, iso-2022-kr, iso-8859-1, iso-8859-13, iso-8859-15, iso-8859-2, iso-8859-3, iso-8859-4, iso-8859-5, iso-8859-6, iso-8859-7, iso-8859-8, iso-8859-9, jis_x0201, jis_x0212-1990, koi8-r, koi8-u, shift_jis, tis-620, us-ascii, utf-16, utf-16be, utf-16le, utf-32, utf-32be, utf-32le, utf-8, windows-1250, windows-1251, windows-1252, windows-1253, windows-1254, windows-1255, windows-1256, windows-1257, windows-1258, windows-31j, x-big5-hkscs-2001, x-big5-solaris, x-euc-jp-linux, x-euc-tw, x-eucjp-open, x-ibm1006, x-ibm1025, x-ibm1046, x-ibm1097, x-ibm1098, x-ibm1112, x-ibm1122, x-ibm1123, x-ibm1124, x-ibm1166, x-ibm1364, x-ibm1381, x-ibm1383, x-ibm300, x-ibm33722, x-ibm737, x-ibm833, x-ibm834, x-ibm856, x-ibm874, x-ibm875, x-ibm921, x-ibm922, x-ibm930, x-ibm933, x-ibm935, x-ibm937, x-ibm939, x-ibm942, x-ibm942c, x-ibm943, x-ibm943c, x-ibm948, x-ibm949, x-ibm949c, x-ibm950, x-ibm964, x-ibm970, x-iscii91, x-iso-2022-cn-cns, x-iso-2022-cn-gb, x-iso-8859-11, x-jis0208, x-jisautodetect, x-johab, x-macarabic, x-maccentraleurope, x-maccroatian, x-maccyrillic, x-macdingbat, x-macgreek, x-machebrew, x-maciceland, x-macroman, x-macromania, x-macsymbol, x-macthai, x-macturkish, x-macukraine, x-ms932_0213, x-ms950-hkscs, x-ms950-hkscs-xp, x-mswin-936, x-pck, x-sjis_0213, x-utf-16le-bom, x-utf-32be-bom, x-utf-32le-bom, x-windows-50220, x-windows-50221, x-windows-874, x-windows-949, x-windows-950, x-windows-iso2022jp[\r][\n]"
2020-06-18 17:10:28.407|DEBUG|http-nio-8090-exec-1|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "Content-Length: 59[\r][\n]"
2020-06-18 17:10:28.407|DEBUG|http-nio-8090-exec-1|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "Host: dev-test.com[\r][\n]"
2020-06-18 17:10:28.407|DEBUG|http-nio-8090-exec-1|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "Connection: Keep-Alive[\r][\n]"
2020-06-18 17:10:28.407|DEBUG|http-nio-8090-exec-1|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "User-Agent: Apache-HttpClient/4.5.10 (Java/1.8.0_201)[\r][\n]"
2020-06-18 17:10:28.407|DEBUG|http-nio-8090-exec-1|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "Accept-Encoding: gzip,deflate[\r][\n]"
2020-06-18 17:10:28.408|DEBUG|http-nio-8090-exec-1|org.apache.http.impl.conn.Wire|wire|73|http-outgoing-0 >> "[\r][\n]"
2020-06-18 17:10:28.408|DEBUG|http-nio-8090-exec-1|org.apache.http.impl.conn.Wire|wire|87|http-outgoing-0 >> "{"devIdList":[164359,164893],"pageSize":10,"currentPage":1}"

和第一次的请求相比，这一次请求日志中多了一句

2020-06-18 17:10:28.408|DEBUG|http-nio-8090-exec-1|org.apache.http.impl.conn.Wire|wire|87|http-outgoing-0 >> "{"devIdList":[164359,164893],"pageSize":10,"currentPage":1}"

如果还没看出来，我在整理一下日志

GET /cross/appms-internal/v1/portal/app/config/search HTTP/1.1[\r][\n]
Accept: text/plain, application/json, application/*+json, */*[\r][\n]
Content-Type: application/json;charset=UTF-8[\r][\n]
Accept-Charset: big5, big5-hkscs, cesu-8, euc-jp, euc-kr, gb18030, gb2312, gbk, ibm-thai, ibm00858, ibm01140, ibm01141, ibm01142, ibm01143, ibm01144, ibm01145, ibm01146, ibm01147, ibm01148, ibm01149, ibm037, ibm1026, ibm1047, ibm273, ibm277, ibm278, ibm280, ibm284, ibm285, ibm290, ibm297, ibm420, ibm424, ibm437, ibm500, ibm775, ibm850, ibm852, ibm855, ibm857, ibm860, ibm861, ibm862, ibm863, ibm864, ibm865, ibm866, ibm868, ibm869, ibm870, ibm871, ibm918, iso-2022-cn, iso-2022-jp, iso-2022-jp-2, iso-2022-kr, iso-8859-1, iso-8859-13, iso-8859-15, iso-8859-2, iso-8859-3, iso-8859-4, iso-8859-5, iso-8859-6, iso-8859-7, iso-8859-8, iso-8859-9, jis_x0201, jis_x0212-1990, koi8-r, koi8-u, shift_jis, tis-620, us-ascii, utf-16, utf-16be, utf-16le, utf-32, utf-32be, utf-32le, utf-8, windows-1250, windows-1251, windows-1252, windows-1253, windows-1254, windows-1255, windows-1256, windows-1257, windows-1258, windows-31j, x-big5-hkscs-2001, x-big5-solaris, x-euc-jp-linux, x-euc-tw, x-eucjp-open, x-ibm1006, x-ibm1025, x-ibm1046, x-ibm1097, x-ibm1098, x-ibm1112, x-ibm1122, x-ibm1123, x-ibm1124, x-ibm1166, x-ibm1364, x-ibm1381, x-ibm1383, x-ibm300, x-ibm33722, x-ibm737, x-ibm833, x-ibm834, x-ibm856, x-ibm874, x-ibm875, x-ibm921, x-ibm922, x-ibm930, x-ibm933, x-ibm935, x-ibm937, x-ibm939, x-ibm942, x-ibm942c, x-ibm943, x-ibm943c, x-ibm948, x-ibm949, x-ibm949c, x-ibm950, x-ibm964, x-ibm970, x-iscii91, x-iso-2022-cn-cns, x-iso-2022-cn-gb, x-iso-8859-11, x-jis0208, x-jisautodetect, x-johab, x-macarabic, x-maccentraleurope, x-maccroatian, x-maccyrillic, x-macdingbat, x-macgreek, x-machebrew, x-maciceland, x-macroman, x-macromania, x-macsymbol, x-macthai, x-macturkish, x-macukraine, x-ms932_0213, x-ms950-hkscs, x-ms950-hkscs-xp, x-mswin-936, x-pck, x-sjis_0213, x-utf-16le-bom, x-utf-32be-bom, x-utf-32le-bom, x-windows-50220, x-windows-50221, x-windows-874, x-windows-949, x-windows-950, x-windows-iso2022jp[\r][\n]
Content-Length: 59[\r][\n]
Host: dev-test.com[\r][\n]
Connection: Keep-Alive[\r][\n]
User-Agent: Apache-HttpClient/4.5.10 (Java/1.8.0_201)[\r][\n]
Accept-Encoding: gzip,deflate[\r][\n]
[\r][\n]

{"devIdList":[164359,164893],"pageSize":10,"currentPage":1}

这个就是HTTP协议，可以看到最后一行就是body里的数据，问题也解决了。

日常问题随笔-RestTemplate发送Get请求通过body传参问题

问题出现

解决问题

测试结果

公司刚入职了一名 Java 中级开发，短短 4 行代码居然凑齐了 3 个 bug！我哭了~~

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