Merge pull request #3814 from TomShiDi/json-getbypath-type-improve

feature: JSON的getByPath方法新增更为通用的指定出参类型重载

hutool-json/src/main/java/cn/hutool/json/JSON.java

@@ -97,6 +97,32 @@ public interface JSON extends Cloneable, Serializable, IJSONTypeConverter {
 	 */
 	<T> T getByPath(String expression, Class<T> resultType);
 
+	/**
+	 * 通过表达式获取JSON中嵌套的对象<br>
+	 * <ol>
+	 * <li>.表达式，可以获取Bean对象中的属性（字段）值或者Map中key对应的值</li>
+	 * <li>[]表达式，可以获取集合等对象中对应index的值</li>
+	 * </ol>
+	 * <p>
+	 * 表达式栗子：
+	 *
+	 * <pre>
+	 * persion
+	 * persion.name
+	 * persons[3]
+	 * person.friends[5].name
+	 * </pre>
+	 * <p>
+	 * 获取表达式对应值后转换为对应类型的值
+	 *
+	 * @param expression 表达式
+	 * @param targetType 返回值类型
+	 * @return 对象
+	 * @see BeanPath#get(Object)
+	 * @since 5.8.34
+	 */
+	<T> T getByPath(String expression, TypeReference<T> targetType);
+
 	/**
 	 * 格式化打印JSON，缩进为4个空格
 	 *

hutool-json/src/main/java/cn/hutool/json/JSONArray.java

@@ -3,6 +3,7 @@ package cn.hutool.json;
 import cn.hutool.core.bean.BeanPath;
 import cn.hutool.core.collection.CollUtil;
 import cn.hutool.core.lang.Filter;
+import cn.hutool.core.lang.TypeReference;
 import cn.hutool.core.lang.Validator;
 import cn.hutool.core.lang.mutable.Mutable;
 import cn.hutool.core.lang.mutable.MutableObj;
@@ -13,6 +14,7 @@ import cn.hutool.json.serialize.JSONWriter;
 
 import java.io.StringWriter;
 import java.io.Writer;
+import java.lang.reflect.Type;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Iterator;
@@ -195,7 +197,7 @@ public class JSONArray implements JSON, JSONGetter<Integer>, List<Object>, Rando
 	 */
 	public String join(String separator) throws JSONException {
 		return StrJoiner.of(separator)
-				.append(this, InternalJSONUtil::valueToString).toString();
+			.append(this, InternalJSONUtil::valueToString).toString();
 	}
 
 	@Override
@@ -218,6 +220,11 @@ public class JSONArray implements JSON, JSONGetter<Integer>, List<Object>, Rando
 		return JSONConverter.jsonConvert(resultType, getByPath(expression), getConfig());
 	}
 
+	@Override
+	public <T> T getByPath(String expression, TypeReference<T> targetType) {
+		return JSONConverter.jsonConvert(targetType, getByPath(expression), getConfig());
+	}
+
 	@Override
 	public void putByPath(String expression, Object value) {
 		BeanPath.create(expression).set(this, value);

hutool-json/src/main/java/cn/hutool/json/JSONObject.java

@@ -3,6 +3,7 @@ package cn.hutool.json;
 import cn.hutool.core.bean.BeanPath;
 import cn.hutool.core.collection.CollectionUtil;
 import cn.hutool.core.lang.Filter;
+import cn.hutool.core.lang.TypeReference;
 import cn.hutool.core.lang.mutable.MutablePair;
 import cn.hutool.core.map.CaseInsensitiveMap;
 import cn.hutool.core.map.MapUtil;
@@ -14,6 +15,7 @@ import cn.hutool.json.serialize.JSONWriter;
 
 import java.io.StringWriter;
 import java.io.Writer;
+import java.lang.reflect.Type;
 import java.math.BigDecimal;
 import java.math.BigInteger;
 import java.util.Collection;
@@ -161,8 +163,8 @@ public class JSONObject extends MapWrapper<String, Object> implements JSON, JSON
 	@Deprecated
 	public JSONObject(Object source, boolean ignoreNullValue, boolean isOrder) {
 		this(source, JSONConfig.create()//
-				.setIgnoreCase((source instanceof CaseInsensitiveMap))//
+			.setIgnoreCase((source instanceof CaseInsensitiveMap))//
-				.setIgnoreNullValue(ignoreNullValue)
+			.setIgnoreNullValue(ignoreNullValue)
 		);
 	}
 
@@ -320,6 +322,11 @@ public class JSONObject extends MapWrapper<String, Object> implements JSON, JSON
 		return JSONConverter.jsonConvert(resultType, getByPath(expression), getConfig());
 	}
 
+	@Override
+	public <T> T getByPath(String expression, TypeReference<T> targetType) {
+		return JSONConverter.jsonConvert(targetType, getByPath(expression), getConfig());
+	}
+
 	@Override
 	public void putByPath(String expression, Object value) {
 		BeanPath.create(expression).set(this, value);
@@ -561,7 +568,7 @@ public class JSONObject extends MapWrapper<String, Object> implements JSON, JSON
 	 */
 	public Writer write(Writer writer, int indentFactor, int indent, Filter<MutablePair<Object, Object>> filter) throws JSONException {
 		final JSONWriter jsonWriter = JSONWriter.of(writer, indentFactor, indent, config)
-				.beginObj();
+			.beginObj();
 		this.forEach((key, value) -> jsonWriter.writeField(new MutablePair<>(key, value), filter));
 		jsonWriter.end();
 		// 此处不关闭Writer，考虑writer后续还需要填内容

hutool-json/src/test/java/cn/hutool/json/JSONPathTest.java

@@ -1,8 +1,12 @@
 package cn.hutool.json;
 
 import static org.junit.jupiter.api.Assertions.*;
+
+import cn.hutool.core.lang.TypeReference;
 import org.junit.jupiter.api.Test;
 
+import java.util.List;
+
 /**
  * JSON路径单元测试
  *
@@ -27,4 +31,23 @@ public class JSONPathTest {
 		Long accountId = JSONUtil.getByPath(json, "$.accountId", 0L);
 		assertEquals(111L, accountId.longValue());
 	}
+
+	@Test
+	public void getByPathTest3(){
+		String str = "[{'accountId':1},{'accountId':2},{'accountId':3}]";
+		JSON json = JSONUtil.parse(str);
+		// 返回指定泛型的对象 List<Long>
+		List<Long> accountIds = json.getByPath("$.accountId", new TypeReference<List<Long>>() {
+		});
+		assertNotNull(accountIds);
+		assertArrayEquals(new Long[]{1L, 2L, 3L}, accountIds.toArray());
+
+		str = "{\"accountInfos\": [{\"accountId\":1},{\"accountId\":2},{\"accountId\":3}]}";
+		json = JSONUtil.parse(str);
+		// 返回指定泛型的对象 List<Long>
+		accountIds = json.getByPath("$.accountInfos.accountId", new TypeReference<List<Long>>() {
+		});
+		assertNotNull(accountIds);
+		assertArrayEquals(new Long[]{1L, 2L, 3L}, accountIds.toArray());
+	}
 }