正文如下
来源：blog.csdn.net/qq_35860138/article/details/82967727
在项目开发中经常会遇到调用第三方接口的情况，比如说调用第三方的天气预报接口。
# 使用流程
1、准备工作：在项目的工具包下导入HttpClientUtil这个工具类，或者也可以使用Spring框架的restTemplate来调用，上面有调用接口的方法【分为Get和Post方式的有参和无参调用】
package com.njsc.credit.util; import java.io.IOException;import java.net.URI;import java.util.ArrayList;import java.util.List;import java.util.Map; import org.apache.http.NameValuePair;import org.apache.http.client.entity.UrlEncodedFormEntity;import org.apache.http.client.methods.CloseableHttpResponse;import org.apache.http.client.methods.HttpGet;import org.apache.http.client.methods.HttpPost;import org.apache.http.client.utils.URIBuilder;import org.apache.http.entity.ContentType;import org.apache.http.entity.StringEntity;import org.apache.http.impl.client.CloseableHttpClient;import org.apache.http.impl.client.HttpClients;import org.apache.http.message.BasicNameValuePair;import org.apache.http.util.EntityUtils; public class HttpClientUtil { /** * 带参数的get请求 * @param url * @param param * @return String */public static String doGet(String url, Map<String, String> param) {// 创建Httpclient对象CloseableHttpClient httpclient = HttpClients.createDefault(); String resultString = "";CloseableHttpResponse response = null;try {// 创建uriURIBuilder builder = new URIBuilder(url);if (param != null) {for (String key : param.keySet()) {builder.addParameter(key, param.get(key));}}URI uri = builder.build();// 创建http GET请求HttpGet httpGet = new HttpGet(uri);// 执行请求response = httpclient.execute(httpGet);// 判断返回状态是否为200if (response.getStatusLine().getStatusCode() == 200) {resultString = EntityUtils.toString(response.getEntity(), "UTF-8");}} catch (Exception e) {e.printStackTrace();} finally {try {if (response != null) {response.close();}httpclient.close();} catch (IOException e) {e.printStackTrace();}}return resultString;} /** * 不带参数的get请求 * @param url * @return String */public static String doGet(String url) {return doGet(url, null);} /** * 带参数的post请求 * @param url * @param param * @return String */public static String doPost(String url, Map<String, String> param) {// 创建Httpclient对象CloseableHttpClient httpClient = HttpClients.createDefault();CloseableHttpResponse response = null;String resultString = "";try {// 创建Http Post请求HttpPost httpPost = new HttpPost(url);// 创建参数列表if (param != null) {List<NameValuePair> paramList = new ArrayList<>();for (String key : param.keySet()) {paramList.add(new BasicNameValuePair(key, param.get(key)));}// 模拟表单UrlEncodedFormEntity entity = new UrlEncodedFormEntity(paramList);httpPost.setEntity(entity);}// 执行http请求response = httpClient.execute(httpPost);resultString = EntityUtils.toString(response.getEntity(), "utf-8");} catch (Exception e) {e.printStackTrace();} finally {try {response.close();} catch (IOException e) {e.printStackTrace();}}return resultString;} /** * 不带参数的post请求 * @param url * @return String */public static String doPost(String url) {return doPost(url, null);} /** * 传送json类型的post请求 * @param url * @param json * @return String */public static String doPostJson(String url, String json) {// 创建Httpclient对象CloseableHttpClient httpClient = HttpClients.createDefault();CloseableHttpResponse response = null;String resultString = "";try {// 创建Http Post请求HttpPost httpPost = new HttpPost(url);// 创建请求内容StringEntity entity = new StringEntity(json, ContentType.APPLICATION_JSON);httpPost.setEntity(entity);// 执行http请求response = httpClient.execute(httpPost);resultString = EntityUtils.toString(response.getEntity(), "utf-8");} catch (Exception e) {e.printStackTrace();} finally {try {response.close();} catch (IOException e) {e.printStackTrace();}}return resultString;}}2、创建url和访问key 以及参数等：
代码如下：
/** * 聚合接口校验身份证 * @param idCard * @param realName * @return boolean */public boolean identityCheck(String idCard, String realName){logger.info("-----------------调用聚合数据 身份证验证API BEGIN--------------->");String key = "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";String url = "http://op.juhe.cn/idcard/query" + "?key=" + key + "&idcard=" + idCard + "&realname=" + realName;logger.info("请求url:" + url);boolean match = false; //是否匹配try {String result = HttpClientUtil.doGet(url);System.out.println("请求结果：" + result);IdentityCheckResult identityCheckResult = JsonUtils.parse(result, IdentityCheckResult.class);IdentityCheck identityCheck = JsonUtils.parse(result, "result", IdentityCheck.class);logger.info(identityCheckResult);logger.info(identityCheck.toString());if(identityCheckResult.correct() && identityCheck.getRes() == 1){match = true;}} catch (Exception e) {e.printStackTrace();}logger.info("<-----------------调用聚合数据 身份证验证API END---------------");return match;}3、请求这个第三方接口：
使用HttpClientUtil工具类中的doGet方法来请求URL，得到结果，现在大多数是一个json字符串，类型为String
4、根据接口返回数据格式来解析数据：
可以看到，返回参数有六个，所以在项目中新建一个bean，包含以上六个字段，用来接住返回数据，如下：
因为接口返回的数据是一个json的字符串，类型实际上是一个String字符串，要解析数据，用工具类JsonUtils的parse方法将字符串转换为Java对象，JsonUtils的代码如下：
package com.eqianxian.commons.utils.json; import java.util.List;import java.util.Map; import com.alibaba.fastjson.JSON;import com.alibaba.fastjson.JSONObject;import com.alibaba.fastjson.serializer.PropertyFilter;import com.alibaba.fastjson.serializer.SerializerFeature; /** * 在系统中统一使用这个，以方便将来切换不同的JSON生成工具 * * @author KelvinZ * */public class JsonUtils {public static final int TYPE_FASTJSON = ;public static final int TYPE_GSON = 1; /** * <pre> * 对象转化为json字符串 * * @param obj 待转化对象 * @return 代表该对象的Json字符串 */public static final String toJson(final Object obj) {return JSON.toJSONString(obj);// return gson.toJson(obj);} /** * <pre> * 对象转化为json字符串 * * @param obj 待转化对象 * @return 代表该对象的Json字符串 */public static final String toJson(final Object obj, SerializerFeature... features) {return JSON.toJSONString(obj, features);// return gson.toJson(obj);} /** * 对象转化为json字符串并格式化 * * @param obj * @param format 是否要格式化 * @return */public static final String toJson(final Object obj, final boolean format) {return JSON.toJSONString(obj, format);} /** * 对象对指定字段进行过滤处理，生成json字符串 * * @param obj * @param fields 过滤处理字段 * @param ignore true做忽略处理，false做包含处理 * @param features json特征，为null忽略 * @return */public static final String toJson(final Object obj, final String[] fields, final boolean ignore,SerializerFeature... features) {if (fields == null || fields.length < 1) {return toJson(obj);}if (features == null)features = new SerializerFeature[] { SerializerFeature.QuoteFieldNames };return JSON.toJSONString(obj, new PropertyFilter() {public boolean apply(Object object, String name, Object value) {for (int i = ; i < fields.length; i++) {if (name.equals(fields[i])) {return !ignore;}}return ignore;}}, features);} /** * <pre> * 解析json字符串中某路径的值 * * @param json * @param path * @return */("unchecked")public static final <E> E parse(final String json, final String path) {String[] keys = path.split(",");JSONObject obj = JSON.parseObject(json);for (int i = ; i < keys.length - 1; i++) {obj = obj.getJSONObject(keys[i]);}return (E) obj.get(keys[keys.length - 1]);} /** * <pre> * json字符串解析为对象 * * @param json 代表一个对象的Json字符串 * @param clazz 指定目标对象的类型，即返回对象的类型 * @return 从json字符串解析出来的对象 */public static final <T> T parse(final String json, final Class<T> clazz) {return JSON.parseObject(json, clazz);} /** * <pre> * json字符串解析为对象 * * @param json json字符串 * @param path 逗号分隔的json层次结构 * @param clazz 目标类 */public static final <T> T parse(final String json, final String path, final Class<T> clazz) {String[] keys = path.split(",");JSONObject obj = JSON.parseObject(json);for (int i = ; i < keys.length - 1; i++) {obj = obj.getJSONObject(keys[i]);}String inner = obj.getString(keys[keys.length - 1]);return parse(inner, clazz);} /** * 将制定的对象经过字段过滤处理后，解析成为json集合 * * @param obj * @param fields * @param ignore * @param clazz * @param features * @return */public static final <T> List<T> parseArray(final Object obj, final String[] fields, boolean ignore,final Class<T> clazz, final SerializerFeature... features) {String json = toJson(obj, fields, ignore, features);return parseArray(json, clazz);} /** * <pre> * 从json字符串中解析出一个对象的集合，被解析字符串要求是合法的集合类型 * （形如:["k1":"v1","k2":"v2",..."kn":"vn"]） * * @param json - [key-value-pair...] * @param clazz * @return */public static final <T> List<T> parseArray(final String json, final Class<T> clazz) {return JSON.parseArray(json, clazz);} /** * <pre> * 从json字符串中按照路径寻找，并解析出一个对象的集合，例如： * 类Person有一个属性name，要从以下json中解析出其集合： * { * "page_info":{ * "items":{ * "item":[{"name":"KelvinZ"},{"name":"Jobs"},...{"name":"Gates"}] * } * } * 使用方法：parseArray(json, "page_info,items,item", Person.class)， * 将根据指定路径，正确的解析出所需集合，排除外层干扰 * * @param json json字符串 * @param path 逗号分隔的json层次结构 * @param clazz 目标类 * @return */public static final <T> List<T> parseArray(final String json, final String path, final Class<T> clazz) {String[] keys = path.split(",");JSONObject obj = JSON.parseObject(json);for (int i = ; i < keys.length - 1; i++) {obj = obj.getJSONObject(keys[i]);}String inner = obj.getString(keys[keys.length - 1]);List<T> ret = parseArray(inner, clazz);return ret;} /** * <pre> * 有些json的常见格式错误这里可以处理，以便给后续的方法处理 * 常见错误：使用了\" 或者 "{ 或者 }"，腾讯的页面中常见这种格式 * * @param invalidJson 包含非法格式的json字符串 * @return */public static final String correctJson(final String invalidJson) {String content = invalidJson.replace("\\\"", "\"").replace("\"{", "{").replace("}\"", "}");return content;} /** * 格式化Json * * @param json * @return */public static final String formatJson(String json) {Map<?, ?> map = (Map<?, ?>) JSON.parse(json);return JSON.toJSONString(map, true);} /** * 获取json串中的子json * * @param json * @param path * @return */public static final String getSubJson(String json, String path) {String[] keys = path.split(",");JSONObject obj = JSON.parseObject(json);for (int i = ; i < keys.length - 1; i++) {obj = obj.getJSONObject(keys[i]);System.out.println(obj.toJSONString());}return obj != null ? obj.getString(keys[keys.length - 1]) : null;} }
