记录工作中对接口的开发

最近工作中分别做了对接别人的接口以及提供接口的工作,在这里做一下总结。

对接别人的接口

主要记录请求http的工具类以及将bean转换为json的工具类
1.请求http工具类,需要引入httpclient-4.5.1.jar以及httpcore-4.4.11.jar

public class HttpUtil {
    /**
     * get请求
     * @return
     */
    public static String doGet(String url) {
        try {
            HttpClient client = new DefaultHttpClient();
            //发送get请求
            HttpGet request = new HttpGet(url);
            HttpResponse response = (HttpResponse) client.execute(request);

            /**请求发送成功,并得到响应**/
            if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                /**读取服务器返回过来的json字符串数据**/
                String strResult = EntityUtils.toString(response.getEntity());

                return strResult;
            }
        }
        catch (IOException e) {
            e.printStackTrace();
        }

        return null;
    }

    /**
     * post请求(用于key-value格式的参数)
     * @param url
     * @param params
     * @return
     */
    public static String doPost(String url, Map params){

        BufferedReader in = null;
        try {
            // 定义HttpClient
            HttpClient client = new DefaultHttpClient();
            // 实例化HTTP方法
            HttpPost request = new HttpPost();
            request.setURI(new URI(url));

            //设置参数
            List<NameValuePair> nvps = new ArrayList<NameValuePair>();
            for (Iterator iter = params.keySet().iterator(); iter.hasNext();) {
                String name = (String) iter.next();
                String value = String.valueOf(params.get(name));
                nvps.add(new BasicNameValuePair(name, value));

                //System.out.println(name +"-"+value);
            }
            request.setEntity(new UrlEncodedFormEntity(nvps, HTTP.UTF_8));

            HttpResponse response = client.execute(request);
            int code = response.getStatusLine().getStatusCode();
            if(code == 200){    //请求成功
                in = new BufferedReader(new InputStreamReader(response.getEntity()
                        .getContent(),"utf-8"));
                StringBuffer sb = new StringBuffer("");
                String line = "";
                String NL = System.getProperty("line.separator");
                while ((line = in.readLine()) != null) {
                    sb.append(line + NL);
                }

                in.close();

                return sb.toString();
            }
            else{   //
                System.out.println("状态码:" + code);
                return null;
            }
        }
        catch(Exception e){
            e.printStackTrace();

            return null;
        }
    }

    /**
     * post请求(用于请求json格式的参数)
     * @param url
     * @param params
     * @return
     */
    public static String doPost(String url, String params) throws Exception {

        CloseableHttpClient httpclient = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost(url);// 创建httpPost
        httpPost.setHeader("Accept", "application/json");
        httpPost.setHeader("Content-Type", "application/json");
        String charSet = "UTF-8";
        StringEntity entity = new StringEntity(params, charSet);
        httpPost.setEntity(entity);
        CloseableHttpResponse response = null;

        try {

            response = httpclient.execute(httpPost);
            StatusLine status = response.getStatusLine();
            int state = status.getStatusCode();
            if (state == HttpStatus.SC_OK) {
                HttpEntity responseEntity = response.getEntity();
                String jsonString = EntityUtils.toString(responseEntity);
                return jsonString;
            }
            else{
                //logger.error("请求返回:"+state+"("+url+")");
                System.out.println("请求返回:"+state+"("+url+")");
            }
        }
        finally {
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            try {
                httpclient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }


}

2.bean转换为json工具类,需要引入jackson-core-asl-1.9.12.jar以及jackson-mapper-asl-1.9.12.jar

@JsonProperty("QaLists")
List<GuoBanImportModel> qaLists;
转换为json的时候JsonProperty注解可以设置字段

public class JsonUtil {

    private static Logger log = LoggerFactory.getLogger(JsonUtil.class);

    private static ObjectMapper objectMapper = new ObjectMapper();
    static{
        //对象的所有字段全部列入
        objectMapper.setSerializationInclusion(Inclusion.ALWAYS);

        //取消默认转换timestamps形式
        objectMapper.configure(SerializationConfig.Feature.WRITE_DATES_AS_TIMESTAMPS,false);

        //忽略空Bean转json的错误
        objectMapper.configure(SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS,false);

        //所有的日期格式都统一为以下的样式,即yyyy-MM-dd HH:mm:ss
        objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));

        //忽略 在json字符串中存在,但是在java对象中不存在对应属性的情况。防止错误
        objectMapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES,false);
    }



    public static <T> String obj2String(T obj){
        if(obj == null){
            return null;
        }
        try {
            return obj instanceof String ? (String)obj :  objectMapper.writeValueAsString(obj);
        } catch (Exception e) {
            log.warn("Parse Object to String error",e);
            return null;
        }
    }

    //格式化
    public static <T> String obj2StringPretty(T obj){
        if(obj == null){
            return null;
        }
        try {
            return obj instanceof String ? (String)obj :  objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(obj);
        } catch (Exception e) {
            log.warn("Parse Object to String error",e);
            return null;
        }
    }


    public static <T> T string2Obj(String str,Class<T> clazz){
        if(StringUtils.isEmpty(str) || clazz == null){
            return null;
        }

        try {
            return clazz.equals(String.class)? (T)str : objectMapper.readValue(str,clazz);
        } catch (Exception e) {
            log.warn("Parse String to Object error",e);
            return null;
        }
    }


    //处理场景:复杂对象包括Map,List,Set
    public static <T> T string2Obj(String str, TypeReference<T> typeReference){
        if(StringUtils.isEmpty(str) || typeReference == null){
            return null;
        }
        try {
            return (T)(typeReference.getType().equals(String.class)? str : objectMapper.readValue(str,typeReference));
        } catch (Exception e) {
            log.warn("Parse String to Object error",e);
            return null;
        }
    }


    //处理场景:可变长参数比较灵活,比如:List<User> userListObj2 = JsonUtil.string2Obj(userListStr,List.class,User.class);
    public static <T> T string2Obj(String str,Class<?> collectionClass,Class<?>... elementClasses){
        JavaType javaType = objectMapper.getTypeFactory().constructParametricType(collectionClass,elementClasses);
        try {
            return objectMapper.readValue(str,javaType);
        } catch (Exception e) {
            log.warn("Parse String to Object error",e);
            return null;
        }
    }
}

提供接口

采用servlet的形式

public class InterfacesServer extends HttpServlet {

    private static final long serialVersionUID = 1L;

    private static final Logger LOGGER = LoggerFactory.getLogger("InterfacesServer");

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        PrintWriter writer = response.getWriter();

        String methodName = request.getRequestURI().split("/")[3];
        LOGGER.info("调用接口名:"+methodName);

        BufferedReader br = null;
        StringBuilder sb = new StringBuilder("");
        try {
            br = request.getReader();
            String str;
            while ((str = br.readLine()) != null) {
                sb.append(str);
            }
            br.close();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (null != br) {
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        String receiveData = sb.toString();//请求传过来的json字符串

        if (StringUtils.isNotBlank(sb.toString())) {
            System.out.println("接收的参数为 :" + sb.toString());
            LOGGER.info("接收的参数为 :" + sb.toString());
        }
        response.setCharacterEncoding("UTF-8");
        response.setContentType("application/json; charset=UTF-8");

        String returnData = "";

        if ("searchNewKnowledge".equals(methodName)){
            ChangChunAddModel model = JSONObject.parseObject(receiveData,ChangChunAddModel.class);
            ServerResponse<List<ChangChunAddModel>> result = searchNewKnowledge(model,request.getRemoteAddr());
            returnData = JSON.toJSONString(result);
        }else if ("searchKnowledge".equals(methodName)){
            KmSearchWSModel model = JSONObject.parseObject(receiveData,KmSearchWSModel.class);
            //ServerResponse<ArrayList<KmSearchWSReturnModel>> result = searchKnowledge(model);
            //returnData = JSON.toJSONString(result);
        }else if ("addKnowledge".equals(methodName)){
            EpistemeModel model = JSONObject.parseObject(receiveData,EpistemeModel.class);
            ServerResponse<T> result = addKnowledge(model, request.getRemoteAddr());
            returnData = JSON.toJSONString(result);
        }

        returnData = URLEncoder.encode(returnData,"UTF-8");
        writer.write(returnData);

        LOGGER.info("返回的参数为:"+returnData);
        System.out.println("---http call success---");
    }

开发中遇到的一些问题:

public String ClobToString(Clob sc) throws SQLException, IOException {
        String reString = "";
        Reader is = sc.getCharacterStream();// 得到流
        BufferedReader br = new BufferedReader(is);
        String s = br.readLine();
        StringBuffer sb = new StringBuffer();
        while (s != null) {// 执行循环将字符串全部取出付值给StringBuffer由StringBuffer转成STRING
            sb.append(s);
            s = br.readLine();
        }
        reString = sb.toString();
        return reString;
    }
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