fix(common): 修复日期解析 int 溢出问题

weixin-java-common/src/main/java/me/chanjar/weixin/common/util/json/WxDateTypeAdapter.java

@@ -35,7 +35,9 @@ public Date read(JsonReader in) throws IOException {
         in.nextNull();
         return null;
       case NUMBER:
-        return new Date(in.nextInt() * 1000);
+        // 微信返回的是秒级时间戳，需转为毫秒；此处必须用 long 读取并运算，
+        // 否则 in.nextInt() * 1000 会发生 int 溢出，导致解析出错误的时间
+        return new Date(in.nextLong() * 1000L);
       default:
         throw new JsonParseException("Expected NUMBER but was " + peek);
     }

weixin-java-common/src/test/java/me/chanjar/weixin/common/util/json/WxDateTypeAdapterTest.java

@@ -0,0 +1,76 @@
+package me.chanjar.weixin.common.util.json;
+
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
+import org.testng.annotations.Test;
+
+import java.io.IOException;
+import java.io.StringReader;
+import java.io.StringWriter;
+import java.util.Date;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * WxDateTypeAdapter 的单元测试.
+ *
+ * @author liyong
+ */
+public class WxDateTypeAdapterTest {
+
+  private final WxDateTypeAdapter adapter = new WxDateTypeAdapter();
+
+  private Date read(String json) throws IOException {
+    JsonReader reader = new JsonReader(new StringReader(json));
+    reader.setLenient(true);
+    return adapter.read(reader);
+  }
+
+  private String write(Date date) throws IOException {
+    StringWriter out = new StringWriter();
+    JsonWriter writer = new JsonWriter(out);
+    writer.setLenient(true);
+    adapter.write(writer, date);
+    return out.toString();
+  }
+
+  /**
+   * 秒级时间戳转成毫秒时如果按 int 运算会溢出，导致解析出的时间错误（甚至早于 1970 年）。
+   */
+  @Test
+  public void testReadCurrentTimestamp() throws IOException {
+    long seconds = 1481013459L;
+    Date date = read(String.valueOf(seconds));
+    assertThat(date).isNotNull();
+    assertThat(date.getTime()).isEqualTo(seconds * 1000L);
+  }
+
+  @Test
+  public void testReadTimestampAfterYear2038() throws IOException {
+    long seconds = 4102444800L;
+    Date date = read(String.valueOf(seconds));
+    assertThat(date).isNotNull();
+    assertThat(date.getTime()).isEqualTo(seconds * 1000L);
+  }
+
+  @Test
+  public void testReadNull() throws IOException {
+    assertThat(read("null")).isNull();
+  }
+
+  @Test
+  public void testWrite() throws IOException {
+    long seconds = 1481013459L;
+    assertThat(write(new Date(seconds * 1000L))).isEqualTo(String.valueOf(seconds));
+    assertThat(write(null)).isEqualTo("null");
+  }
+
+  /**
+   * 序列化与反序列化应当可以互相还原。
+   */
+  @Test
+  public void testWriteThenRead() throws IOException {
+    Date now = new Date(1600000000L * 1000L);
+    assertThat(read(write(now))).isEqualTo(now);
+  }
+}