使用restTemplate进行http接口调用

restTemplate常用方法

• restTemplate是spring封装的http请求调用模板

get请求

• 普通get请求

        RestTemplate restTemplate = new RestTemplate();
        // url请求的地址，第二个参数接收http返回结果的类型
        String url = restTemplate.getForObject("url", String.class);

• 使用UriComponentsBuilder进行参数拼接

        RestTemplate restTemplate = new RestTemplate();
        UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl("url")
                .queryParam("page", 1)
                .queryParam("limit", 10)
                .queryParam("param1", "value1");

        String resp = restTemplate.getForObject(builder.build().toString(), String.class);

• get请求携带header信息

        RestTemplate restTemplate = new RestTemplate();
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);
        // 请求参数和header
        HttpEntity entity = new HttpEntity<>(headers);
        ResponseEntity<String> responseEntity = restTemplate.exchange("url", HttpMethod.GET, entity, String.class);

post请求

• 提交表单 APPLICATION_FORM_URLENCODED

        RestTemplate restTemplate = new RestTemplate();
        // 设置头信息
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);

        // 设置请求boby
        MultiValueMap<String, String> body = new LinkedMultiValueMap<>();
        body.add("param1", "value1");
        body.add("param2", "value2");

        HttpEntity<MultiValueMap<String, String>> entity = new HttpEntity<>(body, headers);
        String resp = restTemplate.postForObject("url", entity, String.class);

• 发送JSON格式请求

        RestTemplate restTemplate = new RestTemplate();
        // 设置头信息
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);

        // 设置请求boby body也可以换成java对象
        Map<String, String> body = new HashMap<>();
        body.put("param1", "value1");
        body.put("param2", "value2");

        HttpEntity<Map<String, String>> entity = new HttpEntity<>(body, headers);
        String resp = restTemplate.postForObject("url", entity, String.class);

• 发送body加密之后的数据

        RestTemplate restTemplate = new RestTemplate();
        // 设置头信息
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);

        // 设置请求boby body也可以换成java对象
        Map<String, String> body = new HashMap<>();
        body.put("param1", "value1");
        body.put("param2", "value2");
        // 加密body
        String encryptBody="把body进行加密";
        HttpEntity<String> entity = new HttpEntity<>(encryptBody, headers);

        // 添加自定义消息转换器
        restTemplate.getMessageConverters().add(new CustomJacksonHttpMessageConverter());
        String resp = restTemplate.postForObject("url", entity, String.class);

自定义消息转换器

• restTemplate默认的是不是解释html返回类型的数据的
• 自定义信息转换器

import org.springframework.http.MediaType;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;

import java.util.Arrays;

/**
 * @author liouwb
 */
public class CustomJacksonHttpMessageConverter extends MappingJackson2HttpMessageConverter {
    public CustomJacksonHttpMessageConverter() {
        setSupportedMediaTypes(Arrays.asList(MediaType.TEXT_PLAIN, 
                MediaType.APPLICATION_JSON, MediaType.TEXT_HTML, 
                new MediaType("application", "*+json")));
    }
}

• 在使用的时候添加自定义信息转换器

        RestTemplate restTemplate = new RestTemplate();
        // 设置头信息
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);

        // 设置请求boby body也可以换成java对象
        Map<String, String> body = new HashMap<>();
        body.put("param1", "value1");
        body.put("param2", "value2");
        HttpEntity<Map<String, String>> entity = new HttpEntity<>(body, headers);

        // 添加自定义消息转换器
        restTemplate.getMessageConverters().add(new CustomJacksonHttpMessageConverter());
        String resp = restTemplate.postForObject("url", entity, String.class);

springboot项目中使用restTemplate并添加自定义消息转换器

/**
 * @author liouwb
 */
@Configuration
public class RestTemplateConfig {
    @Bean
    public RestTemplate restTemplate(RestTemplateBuilder builder) {
        RestTemplate build = builder.build();
        List<HttpMessageConverter<?>> messageConverters = build.getMessageConverters();
        messageConverters.add(new CustomJacksonHttpMessageConverter());
        return build;
    }
}