优化代码，默认属性名为小驼峰命名，数据库列名为下划线命名。

pom.xml

@@ -21,12 +21,6 @@
             <version>0.1.0-SNAPSHOT</version>
         </dependency>
 
-        <dependency>
-            <groupId>org.apache.commons</groupId>
-            <artifactId>commons-lang3</artifactId>
-            <version>3.16.0</version>
-        </dependency>
-
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>

src/main/java/xyz/zhouxy/jdbc/DbRecord.java

@@ -18,9 +18,9 @@ package xyz.zhouxy.jdbc;
 
 import com.google.common.annotations.Beta;
 import com.google.common.base.Preconditions;
-import org.apache.commons.lang3.StringUtils;
 import xyz.zhouxy.plusone.commons.collection.AbstractMapWrapper;
 import xyz.zhouxy.plusone.commons.util.OptionalTools;
+import xyz.zhouxy.plusone.commons.util.StringTools;
 
 import java.util.*;
 
@@ -28,11 +28,11 @@ import java.util.*;
 public class DbRecord extends AbstractMapWrapper<String, Object, DbRecord> {
 
     public DbRecord() {
-        super(new HashMap<>(), k -> Preconditions.checkArgument(StringUtils.isNotBlank(k), "Key must has text."), null);
+        super(new HashMap<>(), k -> Preconditions.checkArgument(StringTools.isNotBlank(k), "Key must has text."), null);
     }
 
     public DbRecord(Map<String, Object> map) {
-        super(map, k -> Preconditions.checkArgument(StringUtils.isNotBlank(k), "Key must has text."), null);
+        super(map, k -> Preconditions.checkArgument(StringTools.isNotBlank(k), "Key must has text."), null);
     }
 
     public Optional<String> getValueAsString(String key) {

src/main/java/xyz/zhouxy/jdbc/DefaultBeanResultMap.java

@@ -33,6 +33,8 @@ import java.util.stream.Collectors;
 
 import javax.annotation.Nullable;
 
+import com.google.common.base.CaseFormat;
+
 public class DefaultBeanResultMap<T> implements ResultMap<T> {
 
     private final Constructor<T> constructor;
@@ -50,24 +52,28 @@ public class DefaultBeanResultMap<T> implements ResultMap<T> {
     public static <T> DefaultBeanResultMap<T> of(Class<T> beanType, @Nullable Map<String, String> propertyColMap)
             throws SQLException {
         try {
-            BeanInfo beanInfo = Introspector.getBeanInfo(beanType);
+            // 获取无参构造器
-            PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
-            Map<String, PropertyDescriptor> colPropertyMap;
-            if (propertyColMap != null && !propertyColMap.isEmpty()) {
-                colPropertyMap = Arrays.stream(propertyDescriptors)
-                        .collect(Collectors.toMap(p -> {
-                            String propertyName = p.getName();
-                            String colName = propertyColMap.get(propertyName);
-                            return colName != null ? colName : propertyName;
-                        }, Function.identity(), (a, b) -> b));
-            }
-            else {
-                colPropertyMap = Arrays.stream(propertyDescriptors)
-                        .collect(Collectors.toMap(PropertyDescriptor::getName, Function.identity(), (a, b) -> b));
-            }
-
             Constructor<T> constructor = beanType.getDeclaredConstructor();
             constructor.setAccessible(true); // NOSONAR
+
+            // 构建 column name 和 PropertyDescriptor 的 映射
+            BeanInfo beanInfo = Introspector.getBeanInfo(beanType);
+            PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
+
+            Function<? super PropertyDescriptor, String> keyMapper;
+            if (propertyColMap == null || propertyColMap.isEmpty()) {
+                keyMapper = p -> CaseFormat.LOWER_CAMEL.to(CaseFormat.LOWER_UNDERSCORE, p.getName());
+            }
+            else {
+                keyMapper = p -> {
+                    String propertyName = p.getName();
+                    String colName = propertyColMap.get(propertyName);
+                    return colName != null ? colName
+                            : CaseFormat.LOWER_CAMEL.to(CaseFormat.LOWER_UNDERSCORE, propertyName);
+                };
+            }
+            Map<String, PropertyDescriptor> colPropertyMap = Arrays.stream(propertyDescriptors).collect(
+                    Collectors.toMap(keyMapper, Function.identity(), (a, b) -> b));
             return new DefaultBeanResultMap<>(constructor, colPropertyMap);
         }
         catch (IntrospectionException e) {

src/test/java/xyz/zhouxy/jdbc/test/SimpleJdbcTemplateTests.java

@@ -22,13 +22,11 @@ import org.junit.jupiter.api.Test;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Lists;
 import com.zaxxer.hikari.HikariConfig;
 import com.zaxxer.hikari.HikariDataSource;
 
 import xyz.zhouxy.jdbc.DbRecord;
-import xyz.zhouxy.jdbc.DefaultBeanResultMap;
 import xyz.zhouxy.jdbc.ResultMap;
 import xyz.zhouxy.jdbc.SimpleJdbcTemplate;
 import xyz.zhouxy.jdbc.SimpleJdbcTemplate.JdbcExecutor;
@@ -229,7 +227,7 @@ class SimpleJdbcTemplateTests {
         Optional<TestBean> t = jdbcTemplate.queryFirst(
                 "SELECT * FROM test_table WHERE id = ?",
                 buildParams(22915),
-                ResultMap.beanResultMap(TestBean.class, ImmutableMap.of("usageDate", "usage_date", "usageDuration", "usage_duration")));
+                ResultMap.beanResultMap(TestBean.class));
         log.info("t: {}", t);
     }
 }