public interface Interceptor {
  Object intercept(Invocation invocation) throws Throwable;
  Object plugin(Object target);
  void setProperties(Properties properties);
}

<plugins>
    <plugin interceptor="com.xx.xx.xxxInterceptor">
        <property name="param1" value="value1"/>
    </plugin>
</plugins>

@Intercepts({ @Signature(type = Executor.class, method = "update", args = { MappedStatement.class, Object.class }),
        @Signature(type = Executor.class, method = "query", args = { MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class }) })

MapperMethod.java
public Object execute(SqlSession sqlSession, Object[] args) {
  Object result;
  if (SqlCommandType.INSERT == command.getType()) {
    Object param = method.convertArgsToSqlCommandParam(args);
    result = rowCountResult(sqlSession.insert(command.getName(), param));
  } else if (SqlCommandType.UPDATE == command.getType()) {
    Object param = method.convertArgsToSqlCommandParam(args);
    result = rowCountResult(sqlSession.update(command.getName(), param));
  } else if (SqlCommandType.DELETE == command.getType()) {
    Object param = method.convertArgsToSqlCommandParam(args);
    result = rowCountResult(sqlSession.delete(command.getName(), param));
  } else if (SqlCommandType.SELECT == command.getType()) {
    if (method.returnsVoid() && method.hasResultHandler()) {
      executeWithResultHandler(sqlSession, args);
      result = null;
    } else if (method.returnsMany()) {
      result = executeForMany(sqlSession, args);
    } else if (method.returnsMap()) {
      result = executeForMap(sqlSession, args);
    } else {
      Object param = method.convertArgsToSqlCommandParam(args);
      result = sqlSession.selectOne(command.getName(), param);
    }
  } else if (SqlCommandType.FLUSH == command.getType()) {
      result = sqlSession.flushStatements();
  } else {
    throw new BindingException("Unknown execution method for: " + command.getName());
  }
  if (result == null && method.getReturnType().isPrimitive() && !method.returnsVoid()) {
    throw new BindingException("Mapper method '" + command.getName()
        + " attempted to return null from a method with a primitive return type (" + method.getReturnType() + ").");
  }
  return result;
}

DefaultSqlSession.java
@Override
public <E> List<E> selectList(String statement, Object parameter, RowBounds rowBounds) {
  try {
    // 從configuration對(duì)象中使用被調(diào)用方法的全路徑，獲取對(duì)應(yīng)的MappedStatement
    MappedStatement ms = configuration.getMappedStatement(statement);
    return executor.query(ms, wrapCollection(parameter), rowBounds, Executor.NO_RESULT_HANDLER);
  } catch (Exception e) {
    throw ExceptionFactory.wrapException("Error querying database.  Cause: " + e, e);
  } finally {
    ErrorContext.instance().reset();
  }
}

SimpleExecutor.java
@Override
public <E> List<E> doQuery(MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler, BoundSql boundSql) throws SQLException {
  Statement stmt = null;
  try {
    Configuration configuration = ms.getConfiguration();
    // 創(chuàng)建StatementHandler，對(duì)應(yīng)第7步
    StatementHandler handler = configuration.newStatementHandler(wrapper, ms, parameter, rowBounds, resultHandler, boundSql);
    // 獲取連接，再調(diào)用conncetion.prepareStatement創(chuàng)建prepareStatement，設(shè)置參數(shù)
    stmt = prepareStatement(handler, ms.getStatementLog());
    // 執(zhí)行prepareStatement
    return handler.<E>query(stmt, resultHandler);
  } finally {
    closeStatement(stmt);
  }
}

Configuration.java
public StatementHandler newStatementHandler(Executor executor, MappedStatement mappedStatement, Object parameterObject, RowBounds rowBounds, ResultHandler resultHandler, BoundSql boundSql) {
  StatementHandler statementHandler = new RoutingStatementHandler(executor, mappedStatement, parameterObject, rowBounds, resultHandler, boundSql);
  // 使用責(zé)任鏈的形式創(chuàng)建代理
  statementHandler = (StatementHandler) interceptorChain.pluginAll(statementHandler);
  return statementHandler;
}
 
InterceptorChain.java
public Object pluginAll(Object target) {
  for (Interceptor interceptor : interceptors) {
    target = interceptor.plugin(target);
  }
  return target;
}

<select id="selectUserList" resultMap="BaseResultMap" parameterType="com.xxx.internet.demo.entity.UserInfo">
        SELECT
        *
        FROM
        `t_user_info`
        <where>
            <if test="phone != null">
                `phone` = #{phone}
            </if>
<!--            明文字段-->
            <if test="secret != null">
                AND `secret` = #{secret}
            </if>
<!--            加密后字段-->
            <if test="secretCiper != null">
                AND `secret_ciper` = #{secretCiper}
            </if>
            <if test="name">
                AND `name` = #{name}
            </if>
        </where>
        ORDER BY `update_time` DESC
    </select>

/**
 * 通過(guò)注解來(lái)表明，我們需要對(duì)那個(gè)字段進(jìn)行加密
 */
@Target({ ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
@Inherited
@Documented
public @interface TEncrypt {
    /**
     * 加密時(shí)從srcKey到destKey
     * @return
     */
    String[] srcKey() default {};
 
    /**
     * 解密時(shí)從destKey到srcKey
     * @return
     */
    String[] destKey() default {};
}

UserMapper.java
public interface UserMapper {
    @TEncrypt(srcKey = {"secret"}, destKey = {"secretCiper"})
    List<UserInfo> selectUserList(UserInfo userInfo);
    }

<mapper namespace="com.xxx.internet.demo.mapper.UserMapper">
    <resultMap id="BaseResultMap" type="com.xxx.internet.demo.entity.UserInfo">
        <id column="id" jdbcType="BIGINT" property="id" />
        <id column="phone" jdbcType="VARCHAR" property="phone"/>
        <id column="secret" jdbcType="VARCHAR" property="secret"/>
<!--        加密后映射-->
        <id column="secret_ciper" jdbcType="VARCHAR" property="secretCiper"/>
        <id column="name" jdbcType="VARCHAR" property="name" />
    </resultMap>
 
    <select id="selectUserList" resultMap="BaseResultMap" parameterType="com.xxx.internet.demo.entity.UserInfo">
        SELECT
        *
        FROM
        `t_user_info`
        <where>
            <if test="phone != null">
                `phone` = #{phone}
            </if>
<!--            明文字段-->
            <if test="secret != null">
                AND `secret` = #{secret}
            </if>
<!--            加密后字段-->
            <if test="secretCiper != null">
                AND `secret_ciper` = #{secretCiper}
            </if>
            <if test="name">
                AND `name` = #{name}
            </if>
        </where>
        ORDER BY `update_time` DESCv
    </select>
</mapper>

@Intercepts({ @Signature(type = Executor.class, method = "update", args = { MappedStatement.class, Object.class }),
        @Signature(type = Executor.class, method = "query", args = { MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class }) })
public class ExecutorEncryptInterceptor implements Interceptor {
    private static final ObjectFactory        DEFAULT_OBJECT_FACTORY         = new DefaultObjectFactory();
 
    private static final ObjectWrapperFactory DEFAULT_OBJECT_WRAPPER_FACTORY = new DefaultObjectWrapperFactory();
 
    private static final ReflectorFactory     REFLECTOR_FACTORY              = new DefaultReflectorFactory();
 
    private static final List<String>         COLLECTION_NAME  = Arrays.asList("list");
 
    private static final String               COUNT_SUFFIX                   = "_COUNT";
 
    @Override
    public Object intercept(Invocation invocation) throws Throwable {
 
        // 獲取攔截器攔截的設(shè)置參數(shù)對(duì)象DefaultParameterHandler
        final Object[] args = invocation.getArgs();
        MappedStatement mappedStatement = (MappedStatement) args[0];
        Object parameterObject = args[1];
 
        // id字段對(duì)應(yīng)執(zhí)行的SQL的方法的全路徑，包含類(lèi)名和方法名
        String id = mappedStatement.getId();
        String className = id.substring(0, id.lastIndexOf("."));
        String methodName = id.substring(id.lastIndexOf(".") + 1);
 
        // 分頁(yè)插件會(huì)生成一個(gè)count語(yǔ)句，這個(gè)語(yǔ)句的參數(shù)也要做處理
        if (methodName.endsWith(COUNT_SUFFIX)) {
            methodName = methodName.substring(0, methodName.lastIndexOf(COUNT_SUFFIX));
        }
 
        // 動(dòng)態(tài)加載類(lèi)并獲取類(lèi)中的方法
        final Method[] methods = Class.forName(className).getMethods();
 
        // 遍歷類(lèi)的所有方法并找到此次調(diào)用的方法
        for (Method method : methods) {
            if (method.getName().equalsIgnoreCase(methodName) && method.isAnnotationPresent(TEncrypt.class)) {
 
                // 獲取方法上的注解以及注解對(duì)應(yīng)的參數(shù)
                TEncrypt paramAnnotation = method.getAnnotation(TEncrypt.class);
 
                // 支持加密的操作，這里只修改參數(shù)
                if (parameterObject instanceof Map) {
                    List<String> paramAnnotations = findParams(method);
                    parameterMapHandler((Map) parameterObject, paramAnnotation, mappedStatement.getSqlCommandType(), paramAnnotations);
                } else {
                    encryptParam(parameterObject, paramAnnotation, mappedStatement.getSqlCommandType());
                }
            }
        }
 
        return invocation.proceed();
    }
}

PageRowBounds rowBounds = new PageRowBounds(0, 10);
List<User> list = userMapper.selectIf(1, rowBounds);
long total = rowBounds.getTotal();