restTemplate常见操作

常见的restTemplate操作

//三种方式 xxForObject、xxForEntity、exchange

//封装请求头
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON_UTF8);//封装请求类型
headers.add("Accept", MediaType.APPLICATION_JSON.toString());//封装可接收类型,"Accept", MediaType.APPLICATION_JSON_VALUE
//封装请求参数
ObjectMapper objectMapper = new ObjectMapper();
String jsonStr = objectMapper.writeValueAsString(map); 
//封装请求实体（请求参数、请求头）
HttpEntity<String> entity = new HttpEntity<>(jsonStr, headers);
//发送请求
Map result = restTemplate.postForObject(expressUrl, entity, Map.class);


//发送携带query参数的uri，使用此api进行编码生成uri
UriComponentsBuilder builder = UriComponentsBuilder
                .fromUriString(getUsersUrl)
                .queryParam("nameOrEmail", nameOrEmail);
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
ResponseEntity<String> exchange = restTemplate.exchange(builder.build().encode().toUri(), HttpMethod.PUT, new HttpEntity<>(headers), String.class);


//发送文件
httpHeaders.setAccept(Arrays.asList(MediaType.MULTIPART_FORM_DATA));
httpHeaders.setContentType(MediaType.MULTIPART_FORM_DATA);
//设置请求体，注意是LinkedMultiValueMap
FileSystemResource fileSystemResource = new FileSystemResource(filePath+"/"+fileName);//获取文件资源
MultiValueMap<String, Object> form = new LinkedMultiValueMap<>();//一个key可以存多个value
form.add("file", fileSystemResource);//封装资源文件 
form.add("filename",fileName);//封装文件名称
//用HttpEntity封装整个请求报文
HttpEntity<MultiValueMap<String, Object>> files = new HttpEntity<>(form, headers);
String s = restTemplate.postForObject(url, files, String.class);

https请求报错

Exception in thread "main" org.springframework.web.client.ResourceAccessException: I/O error on GET request for "https://ecs.gac.com.cn:3351/ecs-console/api/bill/searchBillCount": sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target; nested exception is javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
    
cn.kjjk.kjpayservice.KjPayServiceApplicationTests.main(KjPayServiceApplicationTests.java:58)
Caused by: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

处理方法

RestTemplate restTemplate  = new RestTemplate(new HttpsClientRequestFactory());


public class HttpsClientRequestFactory extends SimpleClientHttpRequestFactory {

    @Override
    protected void prepareConnection(HttpURLConnection connection, String httpMethod) {
        try {
            if (!(connection instanceof HttpsURLConnection)) {// http协议
                //throw new RuntimeException("An instance of HttpsURLConnection is expected");
                super.prepareConnection(connection, httpMethod);
            }
            if (connection instanceof HttpsURLConnection) {// https协议，修改协议版本
                SSLContext ctx = SSLContext.getInstance("TLSv1.2");
                X509TrustManager tm = new X509TrustManager() {
                    @Override
                    public void checkClientTrusted(X509Certificate[] chain,
                                                   String authType) throws CertificateException {
                    }
                    @Override
                    public void checkServerTrusted(X509Certificate[] chain,
                                                   String authType) throws CertificateException {
                    }
                    @Override
                    public X509Certificate[] getAcceptedIssuers() {
                        return null;
                    }
                };
                ctx.init(null, new TrustManager[]{tm}, null);
                org.apache.http.conn.ssl.SSLSocketFactory ssf = new org.apache.http.conn.ssl.SSLSocketFactory(ctx, org.apache.http.conn.ssl.SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);
                ((HttpsURLConnection) connection).setSSLSocketFactory(ctx.getSocketFactory());
                HttpsURLConnection httpsConnection = (HttpsURLConnection) connection;

                super.prepareConnection(httpsConnection, httpMethod);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }