RestTemplate详细配置

1. 配置文件如下

<!-- 声明连接池，指定大小 -->
<bean id="pollingConnectionManager"
    class="org.apache.http.impl.conn.PoolingHttpClientConnectionManager">
    <property name="maxTotal" value="${resttemplate.http.connection.max\_total}" />
    <property name="defaultMaxPerRoute" value="${resttemplate.http.default\_max\_per\_route}" />
</bean>

<!-- 声明http client工厂 -->
<bean id="httpClientBuilder" class="org.apache.http.impl.client.HttpClientBuilder"
    factory-method="create">
    <property name="connectionManager" ref="pollingConnectionManager" />
</bean>

<!-- 声明http client -->
<bean id="httpClient" factory-bean="httpClientBuilder"
    factory-method="build" />

<!-- 声明http rquest工厂，指定超时时间 -->
<bean id="clientHttpRequestFactory"
    class="org.springframework.http.client.HttpComponentsClientHttpRequestFactory">
    <constructor-arg ref="httpClient" />
    <property name="connectTimeout" value="${resttemplate.http.connect\_timeout}" />
    <property name="readTimeout" value="${resttemplate.http.read\_timeout}" />
</bean>

<!-- 声明converter，指定编码 -->
<bean id="utf8TextConverter" class="org.springframework.http.converter.StringHttpMessageConverter">
        <property name="supportedMediaTypes">
            <list>
                <value>text/html;charset=UTF-8</value>
            </list>
        </property>
    </bean>

<!-- 最终的RestTemplate -->
<bean id="restTemplate" class="org.springframework.web.client.RestTemplate">
    <constructor-arg ref="clientHttpRequestFactory" />
    <property name="messageConverters">
        <list>
            <ref bean="utf8TextConverter" />
        </list>
    </property>
</bean>

2. 封装RestTemplate

public class HttpClientWrapper {

protected Logger logger = LoggerFactory.getLogger(HttpClientWrapper.class);

@Autowired
protected RestTemplate restTemplate;

protected ObjectMapper mapper = Jackson2ObjectMapperBuilder.json().build();

/\*\*
 \* 请求指定url，并获得返回对象
 \* @param url http://google.com?key1=value1&key2=value2...
 \* @param method GET
 \* @param tClass XXXResponse.class
 \* @return XXXResponse instance
 \*/
public<T> T request(String url, HttpMethod method, Class<T> tClass) {
    JavaType returnType = TypeFactory.defaultInstance().constructType(
            tClass);
    String content = this.requestForString(url, method, null, null);
    if (content != null) {
        try {
            T object = mapper.readValue(content, returnType);
            return object;
        } catch (JsonParseException e) {
            logger.error("JSON parse exception: \\n");
            logger.error("Content: " + content);
            logger.error(e.getMessage(), e);
        } catch (JsonMappingException e) {
            logger.error("JSON mapping exception: \\n");
            logger.error("Content: " + content);
            logger.error(e.getMessage(), e);
        } catch (IOException e) {
            logger.error(e.getMessage(), e);
        }
    } else {
        logger.error("请求返回空, method:{}, url:{}", method, url);
    }

    return null;

}

/\*\*
 \* 记录Request、Response内容和请求耗时
 \*/
private String requestForString(String url, HttpMethod method,
        Map<String, Object> pathVariables, HttpEntity<String> httpEntity) {
    ResponseEntity<String> response = null;

    if (httpEntity == null) {
        httpEntity = new HttpEntity<String>("");
    }

    this.logRequest(url, method, pathVariables, httpEntity);
    long start = System.currentTimeMillis();
    try {
        if (pathVariables == null) {
            response = restTemplate.exchange(url, method, httpEntity,
                    String.class);
        } else {
            response = restTemplate.exchange(url, method, httpEntity,
                    String.class, pathVariables);
        }
    } catch (Exception e) {
        logger.error(e.getMessage(), e);
        return null;
    }
    long end = System.currentTimeMillis();
    logger.info("Time: " + (end - start));

    if (response.getStatusCode() != HttpStatus.OK) {
        logger.error("Http response is NOT 200, URL: " + method + " " + url
                + "; HTTP status: " + response.getStatusCode());
        return null;
    }

    String content = response.getBody();

    return content;
}

protected void logRequest(String url, HttpMethod method,
        Map<String, Object> pathVariables, HttpEntity<String> httpEntity) {

    if (pathVariables != null) {
        URI expanded = new UriTemplate(url).expand(pathVariables);
        url = expanded.toString();
    }

    logger.info("Http Invoke: " + method + " " + url);
    if (!StringUtils.isEmpty(httpEntity.getBody())) {
        logger.info("Body: " + httpEntity.toString());
    }

}