实现accessToken接口

src/main/java/io/github/dbstarll/weixin/sdk/SecretHolder.java

@@ -0,0 +1,11 @@
+package io.github.dbstarll.weixin.sdk;
+
+public interface SecretHolder {
+    /**
+     * 根据AppId获得Secret.
+     *
+     * @param appId appId
+     * @return appId对应的secret
+     */
+    String getSecret(String appId);
+}

src/main/java/io/github/dbstarll/weixin/sdk/WeChatApi.java

@@ -0,0 +1,80 @@
+package io.github.dbstarll.weixin.sdk;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import io.github.dbstarll.utils.http.client.request.RelativeUriResolver;
+import io.github.dbstarll.utils.json.jackson.JsonApiClient;
+import io.github.dbstarll.utils.net.api.ApiException;
+import org.apache.hc.client5.http.classic.HttpClient;
+import org.apache.hc.core5.http.ClassicHttpRequest;
+import org.apache.hc.core5.http.io.support.ClassicRequestBuilder;
+
+import java.io.IOException;
+
+import static org.apache.commons.lang3.Validate.notBlank;
+import static org.apache.commons.lang3.Validate.notNull;
+
+public class WeChatApi extends JsonApiClient {
+    private final SecretHolder secretHolder;
+
+    /**
+     * 构造WeChatApi.
+     *
+     * @param httpClient   httpClient
+     * @param objectMapper objectMapper
+     * @param secretHolder SecretHolder
+     */
+    public WeChatApi(final HttpClient httpClient, final ObjectMapper objectMapper, final SecretHolder secretHolder) {
+        super(httpClient, true, objectMapper);
+        this.secretHolder = notNull(secretHolder, "secretHolder not set");
+        setUriResolver(new RelativeUriResolver("https://api.weixin.qq.com"));
+    }
+
+    @Override
+    protected <T> T postProcessing(final ClassicHttpRequest request, final T executeResult) throws ApiException {
+        final T superResult = super.postProcessing(request, executeResult);
+        if (superResult instanceof ObjectNode) {
+            final ObjectNode node = (ObjectNode) superResult;
+            final int errcode = node.path("errcode").asInt(0);
+            if (errcode != 0) {
+                throw new WeChatResponseException(errcode, node.path("errmsg").asText());
+            }
+        }
+        return superResult;
+    }
+
+    /**
+     * 登录凭证校验.
+     *
+     * @param appId 小程序 appId
+     * @param code  登录时获取的 code
+     * @return 登录凭证
+     * @throws IOException  in case of a problem or the connection was aborted
+     * @throws ApiException in case of an api error
+     */
+    public ObjectNode session(final String appId, final String code) throws IOException, ApiException {
+        return execute(auth(post("/sns/jscode2session")
+                .addParameter("grant_type", "authorization_code")
+                .addParameter("js_code", notBlank(code, "code not set")), appId), ObjectNode.class);
+    }
+
+    /**
+     * 获取小程序全局唯一后台接口调用凭据，token有效期为7200s，开发者需要进行妥善保存.
+     *
+     * @param appId 小程序唯一凭证，即 AppID，可在「微信公众平台 - 设置 - 开发设置」页中获得
+     * @return 接口调用凭据
+     * @throws IOException  in case of a problem or the connection was aborted
+     * @throws ApiException in case of an api error
+     */
+    public ObjectNode accessToken(final String appId) throws IOException, ApiException {
+        return execute(auth(get("/cgi-bin/token")
+                .addParameter("grant_type", "client_credential"), appId), ObjectNode.class);
+    }
+
+    private ClassicHttpRequest auth(final ClassicRequestBuilder builder, final String appId) {
+        return builder
+                .addParameter("appid", notBlank(appId, "appId not set"))
+                .addParameter("secret", notBlank(secretHolder.getSecret(appId), "secret not found for {}", appId))
+                .build();
+    }
+}

src/main/java/io/github/dbstarll/weixin/sdk/WeChatResponseException.java

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+package io.github.dbstarll.weixin.sdk;
+
+import io.github.dbstarll.utils.net.api.ApiResponseException;
+import org.apache.commons.lang3.StringUtils;
+import org.apache.hc.client5.http.HttpResponseException;
+
+public class WeChatResponseException extends ApiResponseException {
+    private static final String RID_SPLIT_TOKEN = " rid: ";
+
+    private final String rid;
+
+    /**
+     * 构建WeChatResponseException.
+     *
+     * @param errCode 错误码
+     * @param errMsg  错误信息
+     */
+    public WeChatResponseException(final int errCode, final String errMsg) {
+        super(new HttpResponseException(errCode, StringUtils.substringBefore(errMsg, RID_SPLIT_TOKEN)));
+        this.rid = StringUtils.substringAfter(errMsg, RID_SPLIT_TOKEN);
+    }
+
+    /**
+     * 获得rid信息.
+     *
+     * @return rid信息
+     */
+    public final String getRid() {
+        return rid;
+    }
+}

src/test/java/io/github/dbstarll/weixin/sdk/WeChatApiTest.java

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+package io.github.dbstarll.weixin.sdk;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import io.github.dbstarll.utils.http.client.HttpClientFactory;
+import org.apache.hc.client5.http.classic.HttpClient;
+import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.function.ThrowingConsumer;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrowsExactly;
+
+class WeChatApiTest {
+    private void useClient(final ThrowingConsumer<HttpClient> consumer) throws Throwable {
+        try (CloseableHttpClient client = new HttpClientFactory().build()) {
+            consumer.accept(client);
+        }
+    }
+
+    private void useApi(final ThrowingConsumer<WeChatApi> consumer, final SecretHolder secretHolder) throws Throwable {
+        useClient(httpClient -> consumer.accept(new WeChatApi(httpClient, new ObjectMapper(), secretHolder)));
+    }
+
+    @Test
+    void nullSecretHolder() {
+        final Exception e = assertThrowsExactly(NullPointerException.class,
+                () -> useApi(api -> {
+                }, null));
+        assertEquals("secretHolder not set", e.getMessage());
+    }
+
+    @Test
+    void accessToken() throws Throwable {
+        useApi(api -> {
+            final WeChatResponseException e = assertThrowsExactly(WeChatResponseException.class, () -> api.accessToken("appId"));
+            assertEquals(40013, e.getStatusCode());
+            assertEquals("invalid appid", e.getReasonPhrase());
+            assertNotNull(e.getRid());
+        }, appId -> "secret");
+    }
+}