diff --git a/build.gradle b/build.gradle
index 5f8c5e3..4d0b90e 100644
--- a/build.gradle
+++ b/build.gradle
@@ -19,6 +19,20 @@ sourceCompatibility = 1.8
 
 def grpc_java_version = '1.14.0'
 
+tasks.withType(JavaCompile) {
+    options.encoding = "UTF-8"
+}
+
+javadoc {
+    source = sourceSets.main.allJava
+    classpath = configurations.compile
+    options {
+        encoding 'UTF-8'
+        charSet 'UTF-8'
+        title "BDChain Java SDK API"
+    }
+}
+
 protobuf {
     protoc {
         artifact = "com.google.protobuf:protoc:3.6.0"
diff --git a/src/main/java/bdchain/api/AccountingChainClient.java b/src/main/java/bdchain/api/AccountingChainClient.java
index 124b6e1..b146b4c 100644
--- a/src/main/java/bdchain/api/AccountingChainClient.java
+++ b/src/main/java/bdchain/api/AccountingChainClient.java
@@ -15,6 +15,14 @@ import java.util.logging.Logger;
 
 // import bdchain.api.grpc.AccountingChainGrpc.AccountingChainStub;
 
+/**
+ * 记账链客户端
+ *
+ * <p>如有更灵活的需求可直接使用{@link bdchain.api.grpc.AccountingChainGrpc}类。
+ *
+ * @see <a href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#api-1">记账链API</a>
+ * @author nex
+ */
 public class AccountingChainClient {
 
   private static final Logger logger = Logger.getLogger(AccountingChainClient.class.getName());
@@ -22,26 +30,32 @@ public class AccountingChainClient {
   private final ManagedChannel channel;
   private final AccountingChainFutureStub futureStub;
   private final AccountingChainBlockingStub blockingStub;
-  //  private final AccountingChainStub asyncStub;
+//  private final AccountingChainStub asyncStub;
 
-  /** Construct client for accessing AccountingChain server at {@code host:port}. */
+  /** 构造客户端来访问{@code host:port}的记账链服务。 */
   public AccountingChainClient(String host, int port) {
     this(ManagedChannelBuilder.forAddress(host, port).usePlaintext());
   }
 
-  /** Construct client for accessing AccountingChain server using the existing channel. */
+  /** 用已有的{@link io.grpc.Channel}对象构造客户端来访问记账链服务。 */
   public AccountingChainClient(ManagedChannelBuilder<?> channelBuilder) {
     channel = channelBuilder.build();
     AccountingChainGrpc.newFutureStub(channel);
     futureStub = AccountingChainGrpc.newFutureStub(channel);
     blockingStub = AccountingChainGrpc.newBlockingStub(channel);
-    //    asyncStub = AccountingChainGrpc.newStub(channel);
+//    asyncStub = AccountingChainGrpc.newStub(channel);
   }
 
+  /** 关闭客户端的网络连接。 */
   public void shutdown() throws InterruptedException {
     channel.shutdown().awaitTermination(5, TimeUnit.SECONDS);
   }
 
+  /**
+   * <a
+   * href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#blocknumber">返回最新区块的区块号</a>
+   * （非阻塞）
+   */
   public ListenableFuture<BlockNumberResponse> blockNumber(String ledger) {
 
     info("*** blockNumber: ledger={0}", ledger);
@@ -56,6 +70,11 @@ public class AccountingChainClient {
     }
   }
 
+  /**
+   * <a
+   * href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#blocknumber">返回最新区块的区块号</a>
+   * （阻塞）
+   */
   public BlockNumberResponse blockNumberSync(String ledger) {
 
     info("*** blockNumberSync: ledger={0}", ledger);
@@ -70,6 +89,11 @@ public class AccountingChainClient {
     }
   }
 
+  /**
+   * <a
+   * href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#getblockbynumber">返回区块号所指定区块的信息</a>
+   * （非阻塞）
+   */
   public ListenableFuture<Block> getBlockByNumber(
       String ledger, long number, boolean fullTransaction) {
 
@@ -92,6 +116,11 @@ public class AccountingChainClient {
     }
   }
 
+  /**
+   * <a
+   * href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#getblockbynumber">返回区块号所指定区块的信息</a>
+   * （阻塞）
+   */
   public Block getBlockByNumberSync(String ledger, long number, boolean fullTransaction) {
 
     info(
@@ -113,6 +142,11 @@ public class AccountingChainClient {
     }
   }
 
+  /**
+   * <a
+   * href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#getblockbyhash">返回哈希所指定区块的信息</a>
+   * （非阻塞）
+   */
   public ListenableFuture<Block> getBlockByHash(
       String ledger, String hash, boolean fullTransaction) {
 
@@ -135,6 +169,11 @@ public class AccountingChainClient {
     }
   }
 
+  /**
+   * <a
+   * href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#getblockbyhash">返回哈希所指定区块的信息</a>
+   * （阻塞）
+   */
   public Block getBlockByHashSync(String ledger, String hash, boolean fullTransaction) {
 
     info(
@@ -156,6 +195,11 @@ public class AccountingChainClient {
     }
   }
 
+  /**
+   * <a
+   * href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#gettransactionbyhash">返回哈希所指定事务的信息</a>
+   * （非阻塞）
+   */
   public ListenableFuture<Transaction> getTransactionByHash(String ledger, String hash) {
 
     info("*** getTransactionByHash: ledger={0} hash={1}", ledger, hash);
@@ -174,6 +218,11 @@ public class AccountingChainClient {
     }
   }
 
+  /**
+   * <a
+   * href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#gettransactionbyhash">返回哈希所指定事务的信息</a>
+   * （阻塞）
+   */
   public Transaction getTransactionByHashSync(String ledger, String hash) {
 
     info("*** getTransactionByHashSync: ledger={0} hash={1}", ledger, hash);
@@ -192,6 +241,11 @@ public class AccountingChainClient {
     }
   }
 
+  /**
+   * <a
+   * href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#gettransactionbyblocknum">返回区块号与事务index所指定事务的信息</a>
+   * （非阻塞）
+   */
   public ListenableFuture<Transaction> getTransactionByBlockNumberAndIndex(
       String ledger, long block_number, int index) {
 
@@ -214,6 +268,11 @@ public class AccountingChainClient {
     }
   }
 
+  /**
+   * <a
+   * href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#gettransactionbyblocknum">返回区块号与事务index所指定事务的信息</a>
+   * （阻塞）
+   */
   public Transaction getTransactionByBlockNumberAndIndexSync(
       String ledger, long block_number, int index) {
 
@@ -236,6 +295,11 @@ public class AccountingChainClient {
     }
   }
 
+  /**
+   * <a
+   * href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#gettransactionbyblockhas">返回区块的哈希与事务的index所指定事务的信息</a>
+   * （非阻塞）
+   */
   public ListenableFuture<Transaction> getTransactionByBlockHashAndIndex(
       String ledger, String block_hash, int index) {
 
@@ -258,6 +322,11 @@ public class AccountingChainClient {
     }
   }
 
+  /**
+   * <a
+   * href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#gettransactionbyblockhas">返回区块的哈希与事务的index所指定事务的信息</a>
+   * （阻塞）
+   */
   public Transaction getTransactionByBlockHashAndIndexSync(
       String ledger, String block_hash, int index) {
 
diff --git a/src/main/java/bdchain/api/TransactionLedgerClient.java b/src/main/java/bdchain/api/TransactionLedgerClient.java
index a66cae5..421baa2 100644
--- a/src/main/java/bdchain/api/TransactionLedgerClient.java
+++ b/src/main/java/bdchain/api/TransactionLedgerClient.java
@@ -16,6 +16,14 @@ import java.util.logging.Logger;
 
 // import bdchain.api.grpc.TransactionLedgerGrpc.TransactionLedgerStub;
 
+/**
+ * 事务账本客户端
+ *
+ * <p>如有更灵活的需求可直接使用{@link bdchain.api.grpc.TransactionLedgerGrpc}类。
+ *
+ * @see <a href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#api">事务账本API</a>
+ * @author nex
+ */
 public class TransactionLedgerClient {
 
   private static final Logger logger = Logger.getLogger(TransactionLedgerClient.class.getName());
@@ -25,12 +33,12 @@ public class TransactionLedgerClient {
   private final TransactionLedgerBlockingStub blockingStub;
   //  private final TransactionLedgerStub asyncStub;
 
-  /** Construct client for accessing TransactionLedger server at {@code host:port}. */
+  /** 构造客户端来访问{@code host:port}的事务账本服务。 */
   public TransactionLedgerClient(String host, int port) {
     this(ManagedChannelBuilder.forAddress(host, port).usePlaintext());
   }
 
-  /** Construct client for accessing TransactionLedger server using the existing channel. */
+  /** 用已有的{@link io.grpc.Channel}对象构造客户端来访问事务账本服务。 */
   public TransactionLedgerClient(ManagedChannelBuilder<?> channelBuilder) {
     channel = channelBuilder.build();
     futureStub = TransactionLedgerGrpc.newFutureStub(channel);
@@ -38,10 +46,15 @@ public class TransactionLedgerClient {
     //    asyncStub = TransactionLedgerGrpc.newStub(channel);
   }
 
+  /** 关闭客户端的网络连接。 */
   public void shutdown() throws InterruptedException {
     channel.shutdown().awaitTermination(5, TimeUnit.SECONDS);
   }
 
+  /**
+   * <a href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#createledger">创建账本</a>
+   * （非阻塞）
+   */
   public ListenableFuture<CreateLedgerResponse> createLedger(String name) {
 
     info("*** createLedger: name={0}", name);
@@ -56,6 +69,10 @@ public class TransactionLedgerClient {
     }
   }
 
+  /**
+   * <a href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#createledger">创建账本</a>
+   * （阻塞）
+   */
   public CreateLedgerResponse createLedgerSync(String name) {
 
     info("*** createLedgerSync: name={0}", name);
@@ -70,6 +87,10 @@ public class TransactionLedgerClient {
     }
   }
 
+  /**
+   * <a href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#getledgers">返回账本列表</a>
+   * （非阻塞）
+   */
   public ListenableFuture<GetLedgersResponse> getLedgers() {
 
     info("*** getLedgers");
@@ -82,6 +103,10 @@ public class TransactionLedgerClient {
     }
   }
 
+  /**
+   * <a href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#getledgers">返回账本列表</a>
+   * （阻塞）
+   */
   public GetLedgersResponse getLedgersSync() {
 
     info("*** getLedgersSync");
@@ -94,6 +119,11 @@ public class TransactionLedgerClient {
     }
   }
 
+  /**
+   * <a
+   * href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#sendtransaction">发送新事务</a>
+   * （非阻塞）
+   */
   public ListenableFuture<SendTransactionResponse> sendTransaction(
       String ledger, TransactionType type, String from, String to, byte[] data) {
 
@@ -120,6 +150,11 @@ public class TransactionLedgerClient {
     }
   }
 
+  /**
+   * <a
+   * href="https://phabricator.internetapi.cn/w/public/bdchain/grpc-api/#sendtransaction">发送新事务</a>
+   * （阻塞）
+   */
   public SendTransactionResponse sendTransactionSync(
       String ledger, TransactionType type, String from, String to, byte[] data) {