fix code to replace join

hutool-core/src/main/java/cn/hutool/core/collection/ArrayIter.java

@@ -7,46 +7,68 @@ import java.util.NoSuchElementException;
 
 /**
  * 数组Iterator对象
- * @author Looly
  *
  * @param <E> 元素类型
+ * @author Looly
  * @since 4.1.1
  */
 public class ArrayIter<E> implements Iterator<E>, Iterable<E>, Serializable {
 	private static final long serialVersionUID = 1L;
 
-	/** 数组 */
+	/**
+	 * 数组
+	 */
 	private final Object array;
-	/** 起始位置 */
+	/**
+	 * 起始位置
+	 */
 	private int startIndex;
-	/** 结束位置 */
+	/**
+	 * 结束位置
+	 */
 	private int endIndex;
-	/** 当前位置 */
+	/**
+	 * 当前位置
+	 */
 	private int index;
 
 	/**
 	 * 构造
+	 *
 	 * @param array 数组
 	 * @throws IllegalArgumentException array对象不为数组抛出此异常
 	 * @throws NullPointerException     array对象为null
 	 */
-	public ArrayIter(final Object array) {
+	public ArrayIter(E[] array) {
+		this((Object) array);
+	}
+
+	/**
+	 * 构造
+	 *
+	 * @param array 数组
+	 * @throws IllegalArgumentException array对象不为数组抛出此异常
+	 * @throws NullPointerException     array对象为null
+	 */
+	public ArrayIter(Object array) {
 		this(array, 0);
 	}
 
 	/**
 	 * 构造
+	 *
 	 * @param array      数组
 	 * @param startIndex 起始位置，当起始位置小于0或者大于结束位置，置为0。
 	 * @throws IllegalArgumentException array对象不为数组抛出此异常
 	 * @throws NullPointerException     array对象为null
 	 */
-	public ArrayIter(final Object array, final int startIndex) {
+	public ArrayIter(Object array, int startIndex) {
 		this(array, startIndex, -1);
 	}
 
 	/**
 	 * 构造
+	 *
 	 * @param array      数组
 	 * @param startIndex 起始位置，当起始位置小于0或者大于结束位置，置为0。
 	 * @param endIndex   结束位置，当结束位置小于0或者大于数组长度，置为数组长度。
@@ -82,6 +104,7 @@ public class ArrayIter<E> implements Iterator<E>, Iterable<E>, Serializable{
 
 	/**
 	 * 不允许操作数组元素
+	 *
 	 * @throws UnsupportedOperationException always
 	 */
 	@Override
@@ -91,6 +114,7 @@ public class ArrayIter<E> implements Iterator<E>, Iterable<E>, Serializable{
 
 	// Properties
 	// -----------------------------------------------------------------------
+
 	/**
 	 * 获得原始数组对象
 	 *

hutool-core/src/main/java/cn/hutool/core/collection/IterUtil.java

@@ -6,10 +6,8 @@ import cn.hutool.core.lang.Filter;
 import cn.hutool.core.lang.func.Func1;
 import cn.hutool.core.map.MapUtil;
 import cn.hutool.core.text.StrJoiner;
-import cn.hutool.core.util.ArrayUtil;
 import cn.hutool.core.util.ObjectUtil;
 import cn.hutool.core.util.ReflectUtil;
-import cn.hutool.core.util.StrUtil;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -246,7 +244,7 @@ public class IterUtil {
 	 * @return 连接后的字符串
 	 */
 	public static <T> String join(Iterator<T> iterator, CharSequence conjunction) {
-		return join(iterator, conjunction, null, null);
+		return StrJoiner.of(conjunction).append(iterator).toString();
 	}
 
 	/**
@@ -262,17 +260,11 @@ public class IterUtil {
 	 * @since 4.0.10
 	 */
 	public static <T> String join(Iterator<T> iterator, CharSequence conjunction, String prefix, String suffix) {
-		return join(iterator, conjunction, (item) -> {
-			if (ArrayUtil.isArray(item)) {
-				return ArrayUtil.join(ArrayUtil.wrap(item), conjunction, prefix, suffix);
-			} else if (item instanceof Iterable) {
-				return CollUtil.join((Iterable<?>) item, conjunction, prefix, suffix);
-			} else if (item instanceof Iterator) {
-				return join((Iterator<?>) item, conjunction, prefix, suffix);
-			} else {
-				return StrUtil.wrap(String.valueOf(item), prefix, suffix);
-			}
-		});
+		return StrJoiner.of(conjunction, prefix, suffix)
+				// 每个元素都添加前后缀
+				.setWrapElement(true)
+				.append(iterator)
+				.toString();
 	}
 
 	/**
@@ -291,7 +283,7 @@ public class IterUtil {
 			return null;
 		}
 
-		return new StrJoiner(conjunction).append(iterator, func).toString();
+		return StrJoiner.of(conjunction).append(iterator, func).toString();
 	}
 
 	/**

hutool-core/src/main/java/cn/hutool/core/io/resource/ClassPathResource.java

@@ -1,7 +1,5 @@
 package cn.hutool.core.io.resource;
 
-import java.net.URL;
-
 import cn.hutool.core.io.FileUtil;
 import cn.hutool.core.lang.Assert;
 import cn.hutool.core.util.ClassUtil;
@@ -9,6 +7,8 @@ import cn.hutool.core.util.ObjectUtil;
 import cn.hutool.core.util.StrUtil;
 import cn.hutool.core.util.URLUtil;
 
+import java.net.URL;
+
 /**
  * ClassPath单一资源访问类<br>
  * 传入路径path必须为相对路径，如果传入绝对路径，Linux路径会去掉开头的“/”，而Windows路径会直接报错。<br>

hutool-core/src/main/java/cn/hutool/core/text/StrJoiner.java

@@ -22,11 +22,38 @@ public class StrJoiner implements Appendable {
 	private CharSequence delimiter;
 	private CharSequence prefix;
 	private CharSequence suffix;
-	/**
-	 * appendable中是否包含内容
-	 */
+	// 前缀和后缀是否包装每个元素，true表示包装每个元素，false包装整个字符串
+	private boolean wrapElement;
+	// null元素处理逻辑
+	private NullMode nullMode = NullMode.NULL_STRING;
+	// 当结果为空时默认返回的拼接结果
+	private String emptyResult = StrUtil.EMPTY;
+
+	// appendable中是否包含内容，用于判断增加内容时，是否首先加入分隔符
 	private boolean hasContent;
 
+	/**
+	 * 使用指定分隔符创建{@link StrJoiner}
+	 *
+	 * @param delimiter 分隔符
+	 * @return {@link StrJoiner}
+	 */
+	public static StrJoiner of(CharSequence delimiter) {
+		return new StrJoiner(delimiter);
+	}
+
+	/**
+	 * 使用指定分隔符创建{@link StrJoiner}
+	 *
+	 * @param delimiter 分隔符
+	 * @param prefix    前缀
+	 * @param suffix    后缀
+	 * @return {@link StrJoiner}
+	 */
+	public static StrJoiner of(CharSequence delimiter, CharSequence prefix, CharSequence suffix) {
+		return new StrJoiner(delimiter, prefix, suffix);
+	}
+
 	/**
 	 * 构造
 	 *
@@ -69,11 +96,7 @@ public class StrJoiner implements Appendable {
 					 CharSequence prefix, CharSequence suffix) {
 		if (null != appendable) {
 			this.appendable = appendable;
-			final String initStr = appendable.toString();
-			if (StrUtil.isNotEmpty(initStr) && false == StrUtil.endWith(initStr, delimiter)) {
-				// 用户传入的Appendable中已经存在内容，且末尾不是分隔符
-				this.hasContent = true;
-			}
+			checkHasContent(appendable);
 		}
 
 		this.delimiter = delimiter;
@@ -115,14 +138,72 @@ public class StrJoiner implements Appendable {
 	}
 
 	/**
-	 * 追加{@link Iterator}中的元素到拼接器中
+	 * 设置前缀和后缀是否包装每个元素
 	 *
-	 * @param <T>       元素类型
-	 * @param iterable  元素列表
+	 * @param wrapElement true表示包装每个元素，false包装整个字符串
 	 * @return this
 	 */
-	public <T> StrJoiner append(Iterable<T> iterable) {
-		return append(IterUtil.getIter(iterable));
+	public StrJoiner setWrapElement(boolean wrapElement) {
+		this.wrapElement = wrapElement;
+		return this;
+	}
+
+	/**
+	 * 设置{@code null}元素处理逻辑
+	 *
+	 * @param nullMode 逻辑枚举，可选忽略、转换为""或转换为null字符串
+	 * @return this
+	 */
+	public StrJoiner setNullMode(NullMode nullMode) {
+		this.nullMode = nullMode;
+		return this;
+	}
+
+	/**
+	 * 设置当没有任何元素加入时，默认返回的字符串，默认""
+	 *
+	 * @param emptyResult 默认字符串
+	 * @return this
+	 */
+	public StrJoiner setEmptyResult(String emptyResult) {
+		this.emptyResult = emptyResult;
+		return this;
+	}
+
+	/**
+	 * 追加对象到拼接器中
+	 *
+	 * @param <T> 元素类型
+	 * @param obj 对象，支持数组、集合等
+	 * @return this
+	 */
+	public <T> StrJoiner append(Object obj) {
+		if (null == obj) {
+			append((CharSequence) null);
+		} else if (ArrayUtil.isArray(obj)) {
+			append(new ArrayIter<>(obj));
+		} else if (obj instanceof Iterator) {
+			append((Iterator<?>) obj);
+		} else if (obj instanceof Iterable) {
+			append(((Iterable<?>) obj).iterator());
+		} else {
+			append(String.valueOf(obj));
+		}
+		return this;
+	}
+
+	/**
+	 * 追加数组中的元素到拼接器中
+	 *
+	 * @param <T>   元素类型
+	 * @param array 元素数组
+	 * @return this
+	 */
+	public <T> StrJoiner append(T[] array) {
+		if(null == array){
+			return this;
+		}
+		return append(new ArrayIter<>(array));
 	}
 
 	/**
@@ -133,16 +214,22 @@ public class StrJoiner implements Appendable {
 	 * @return this
 	 */
 	public <T> StrJoiner append(Iterator<T> iterator) {
-		return append(iterator, (t)->{
-			if(ArrayUtil.isArray(t)){
-				return new StrJoiner(this.delimiter).append((Iterator<?>) new ArrayIter<>(t)).toString();
-			} else if(t instanceof Iterator){
-				return new StrJoiner(this.delimiter).append((Iterator<?>)t).toString();
-			} else if(t instanceof Iterable){
-				return new StrJoiner(this.delimiter).append((Iterable<?>)t).toString();
+		if(null == iterator){
+			return this;
 		}
-			return String.valueOf(t);
-		});
+		return append(iterator, (t) -> StrJoiner.of(this.delimiter).append(t).toString());
+	}
+
+	/**
+	 * 追加数组中的元素到拼接器中
+	 *
+	 * @param <T>       元素类型
+	 * @param array     元素数组
+	 * @param toStrFunc 元素对象转换为字符串的函数
+	 * @return this
+	 */
+	public <T> StrJoiner append(T[] array, Function<T, ? extends CharSequence> toStrFunc) {
+		return append((Iterator<T>) new ArrayIter<>(array), toStrFunc);
 	}
 
 	/**
@@ -176,8 +263,26 @@ public class StrJoiner implements Appendable {
 
 	@Override
 	public StrJoiner append(CharSequence csq) {
+		if (null == csq) {
+			switch (this.nullMode) {
+				case IGNORE:
+					return this;
+				case TO_EMPTY:
+					csq = StrUtil.EMPTY;
+					break;
+				case NULL_STRING:
+					csq = StrUtil.NULL;
+			}
+		}
 		try {
-			prepare().append(csq);
+			final Appendable appendable = prepare();
+			if (wrapElement && StrUtil.isNotEmpty(this.prefix)) {
+				appendable.append(prefix);
+			}
+			appendable.append(csq);
+			if (wrapElement && StrUtil.isNotEmpty(this.suffix)) {
+				appendable.append(suffix);
+			}
 		} catch (IOException e) {
 			throw new IORuntimeException(e);
 		}
@@ -185,35 +290,46 @@ public class StrJoiner implements Appendable {
 	}
 
 	@Override
-	public StrJoiner append(CharSequence csq, int start, int end) {
-		try {
-			prepare().append(csq, start, end);
-		} catch (IOException e) {
-			throw new IORuntimeException(e);
-		}
-		return this;
+	public StrJoiner append(CharSequence csq, int startInclude, int endExclude) {
+		return append(StrUtil.sub(csq, startInclude, endExclude));
 	}
 
 	@Override
 	public StrJoiner append(char c) {
-		try {
-			prepare().append(c);
-		} catch (IOException e) {
-			throw new IORuntimeException(e);
-		}
-		return this;
+		return append(String.valueOf(c));
 	}
 
 	@Override
 	public String toString() {
-		if (StrUtil.isNotEmpty(this.suffix)) {
+		if(null == this.appendable){
+			return emptyResult;
+		}
+		if (false == wrapElement && StrUtil.isNotEmpty(this.suffix)) {
 			try {
-				appendable.append(this.suffix);
+				this.appendable.append(this.suffix);
 			} catch (IOException e) {
 				throw new IORuntimeException(e);
 			}
 		}
-		return appendable.toString();
+		return this.appendable.toString();
+	}
+
+	/**
+	 * {@code null}处理的模式
+	 */
+	public enum NullMode {
+		/**
+		 * 忽略{@code null}，即null元素不加入拼接的字符串
+		 */
+		IGNORE,
+		/**
+		 * {@code null}转为""
+		 */
+		TO_EMPTY,
+		/**
+		 * {@code null}转为null字符串
+		 */
+		NULL_STRING
 	}
 
 	/**
@@ -226,12 +342,33 @@ public class StrJoiner implements Appendable {
 		if (hasContent) {
 			this.appendable.append(delimiter);
 		} else {
+			if (null == this.appendable) {
 				this.appendable = new StringBuilder();
-			if (StrUtil.isNotEmpty(this.prefix)) {
+			}
+			if (false == wrapElement && StrUtil.isNotEmpty(this.prefix)) {
 				this.appendable.append(this.prefix);
 			}
 			this.hasContent = true;
 		}
 		return this.appendable;
 	}
+
+	/**
+	 * 检查用户传入的{@link Appendable} 是否已经存在内容，而且不能以分隔符结尾
+	 *
+	 * @param appendable {@link Appendable}
+	 */
+	private void checkHasContent(Appendable appendable) {
+		if (appendable instanceof CharSequence) {
+			final CharSequence charSequence = (CharSequence) appendable;
+			if (charSequence.length() > 0 && StrUtil.endWith(charSequence, delimiter)) {
+				this.hasContent = true;
+			}
+		} else {
+			final String initStr = appendable.toString();
+			if (StrUtil.isNotEmpty(initStr) && false == StrUtil.endWith(initStr, delimiter)) {
+				this.hasContent = true;
+			}
+		}
+	}
 }

hutool-core/src/main/java/cn/hutool/core/util/ArrayUtil.java

@@ -2,7 +2,6 @@ package cn.hutool.core.util;
 
 import cn.hutool.core.collection.CollUtil;
 import cn.hutool.core.collection.CollectionUtil;
-import cn.hutool.core.collection.IterUtil;
 import cn.hutool.core.comparator.CompareUtil;
 import cn.hutool.core.exceptions.UtilException;
 import cn.hutool.core.lang.Assert;
@@ -10,6 +9,7 @@ import cn.hutool.core.lang.Editor;
 import cn.hutool.core.lang.Filter;
 import cn.hutool.core.lang.Matcher;
 import cn.hutool.core.map.MapUtil;
+import cn.hutool.core.text.StrJoiner;
 
 import java.lang.reflect.Array;
 import java.nio.ByteBuffer;
@@ -1116,36 +1116,22 @@ public class ArrayUtil extends PrimitiveArrayUtil {
 	 *
 	 * @param <T>       被处理的集合
 	 * @param array     数组
-	 * @param conjunction 分隔符
+	 * @param delimiter 分隔符
 	 * @param prefix    每个元素添加的前缀，null表示不添加
 	 * @param suffix    每个元素添加的后缀，null表示不添加
 	 * @return 连接后的字符串
 	 * @since 4.0.10
 	 */
-	public static <T> String join(T[] array, CharSequence conjunction, String prefix, String suffix) {
+	public static <T> String join(T[] array, CharSequence delimiter, String prefix, String suffix) {
 		if (null == array) {
 			return null;
 		}
 
-		final StringBuilder sb = new StringBuilder();
-		boolean isFirst = true;
-		for (T item : array) {
-			if (isFirst) {
-				isFirst = false;
-			} else {
-				sb.append(conjunction);
-			}
-			if (ArrayUtil.isArray(item)) {
-				sb.append(join(ArrayUtil.wrap(item), conjunction, prefix, suffix));
-			} else if (item instanceof Iterable<?>) {
-				sb.append(CollUtil.join((Iterable<?>) item, conjunction, prefix, suffix));
-			} else if (item instanceof Iterator<?>) {
-				sb.append(IterUtil.join((Iterator<?>) item, conjunction, prefix, suffix));
-			} else {
-				sb.append(StrUtil.wrap(StrUtil.toString(item), prefix, suffix));
-			}
-		}
-		return sb.toString();
+		return StrJoiner.of(delimiter, prefix, suffix)
+				// 每个元素都添加前后缀
+				.setWrapElement(true)
+				.append(array)
+				.toString();
 	}
 
 	/**
@@ -1159,26 +1145,7 @@ public class ArrayUtil extends PrimitiveArrayUtil {
 	 * @since 5.3.3
 	 */
 	public static <T> String join(T[] array, CharSequence conjunction, Editor<T> editor) {
-		if (null == array) {
-			return null;
-		}
-
-		final StringBuilder sb = new StringBuilder();
-		boolean isFirst = true;
-		for (T item : array) {
-			if (isFirst) {
-				isFirst = false;
-			} else {
-				sb.append(conjunction);
-			}
-			if (null != editor) {
-				item = editor.edit(item);
-			}
-			if (null != item) {
-				sb.append(StrUtil.toString(item));
-			}
-		}
-		return sb.toString();
+		return StrJoiner.of(conjunction).append(array, (t)-> String.valueOf(editor.edit(t))).toString();
 	}
 
 	/**
@@ -1190,38 +1157,13 @@ public class ArrayUtil extends PrimitiveArrayUtil {
 	 */
 	public static String join(Object array, CharSequence conjunction) {
 		if (null == array) {
-			throw new NullPointerException("Array must be not null!");
+			return null;
 		}
 		if (false == isArray(array)) {
 			throw new IllegalArgumentException(StrUtil.format("[{}] is not a Array!", array.getClass()));
 		}
 
-		final Class<?> componentType = array.getClass().getComponentType();
-		if (componentType.isPrimitive()) {
-			final String componentTypeName = componentType.getName();
-			switch (componentTypeName) {
-				case "long":
-					return join((long[]) array, conjunction);
-				case "int":
-					return join((int[]) array, conjunction);
-				case "short":
-					return join((short[]) array, conjunction);
-				case "char":
-					return join((char[]) array, conjunction);
-				case "byte":
-					return join((byte[]) array, conjunction);
-				case "boolean":
-					return join((boolean[]) array, conjunction);
-				case "float":
-					return join((float[]) array, conjunction);
-				case "double":
-					return join((double[]) array, conjunction);
-				default:
-					throw new UtilException("Unknown primitive type: [{}]", componentTypeName);
-			}
-		} else {
-			return join((Object[]) array, conjunction);
-		}
+		return StrJoiner.of(conjunction).append(array).toString();
 	}
 
 	/**

hutool-core/src/main/java/cn/hutool/core/util/PrimitiveArrayUtil.java

@@ -1593,8 +1593,9 @@ public class PrimitiveArrayUtil {
 	 *
 	 * @param array       数组
 	 * @param conjunction 分隔符
-	 * @return 连接后的字符串
+	 * @deprecated 请使用 {@link ArrayUtil#join(Object, CharSequence)}
 	 */
+	@Deprecated
 	public static String join(int[] array, CharSequence conjunction) {
 		if (null == array) {
 			return null;
@@ -1618,8 +1619,9 @@ public class PrimitiveArrayUtil {
 	 *
 	 * @param array       数组
 	 * @param conjunction 分隔符
-	 * @return 连接后的字符串
+	 * @deprecated 请使用 {@link ArrayUtil#join(Object, CharSequence)}
 	 */
+	@Deprecated
 	public static String join(long[] array, CharSequence conjunction) {
 		if (null == array) {
 			return null;
@@ -1643,8 +1645,9 @@ public class PrimitiveArrayUtil {
 	 *
 	 * @param array       数组
 	 * @param conjunction 分隔符
-	 * @return 连接后的字符串
+	 * @deprecated 请使用 {@link ArrayUtil#join(Object, CharSequence)}
 	 */
+	@Deprecated
 	public static String join(short[] array, CharSequence conjunction) {
 		if (null == array) {
 			return null;
@@ -1668,8 +1671,9 @@ public class PrimitiveArrayUtil {
 	 *
 	 * @param array       数组
 	 * @param conjunction 分隔符
-	 * @return 连接后的字符串
+	 * @deprecated 请使用 {@link ArrayUtil#join(Object, CharSequence)}
 	 */
+	@Deprecated
 	public static String join(char[] array, CharSequence conjunction) {
 		if (null == array) {
 			return null;
@@ -1693,8 +1697,9 @@ public class PrimitiveArrayUtil {
 	 *
 	 * @param array       数组
 	 * @param conjunction 分隔符
-	 * @return 连接后的字符串
+	 * @deprecated 请使用 {@link ArrayUtil#join(Object, CharSequence)}
 	 */
+	@Deprecated
 	public static String join(byte[] array, CharSequence conjunction) {
 		if (null == array) {
 			return null;
@@ -1719,7 +1724,9 @@ public class PrimitiveArrayUtil {
 	 * @param array       数组
 	 * @param conjunction 分隔符
 	 * @return 连接后的字符串
+	 * @deprecated 请使用 {@link ArrayUtil#join(Object, CharSequence)}
 	 */
+	@Deprecated
 	public static String join(boolean[] array, CharSequence conjunction) {
 		if (null == array) {
 			return null;
@@ -1744,7 +1751,9 @@ public class PrimitiveArrayUtil {
 	 * @param array       数组
 	 * @param conjunction 分隔符
 	 * @return 连接后的字符串
+	 * @deprecated 请使用 {@link ArrayUtil#join(Object, CharSequence)}
 	 */
+	@Deprecated
 	public static String join(float[] array, CharSequence conjunction) {
 		if (null == array) {
 			return null;
@@ -1769,7 +1778,9 @@ public class PrimitiveArrayUtil {
 	 * @param array       数组
 	 * @param conjunction 分隔符
 	 * @return 连接后的字符串
+	 * @deprecated 请使用 {@link ArrayUtil#join(Object, CharSequence)}
 	 */
+	@Deprecated
 	public static String join(double[] array, CharSequence conjunction) {
 		if (null == array) {
 			return null;

hutool-core/src/test/java/cn/hutool/core/collection/IterUtilTest.java

@@ -32,6 +32,7 @@ public class IterUtilTest {
 		String join1 = IterUtil.join(list1.iterator(), ":");
 		Assert.assertEquals("1:2:3:4", join1);
 
+		// 包装每个节点
 		ArrayList<String> list2 = CollUtil.newArrayList("1", "2", "3", "4");
 		String join2 = IterUtil.join(list2.iterator(), ":", "\"", "\"");
 		Assert.assertEquals("\"1\":\"2\":\"3\":\"4\"", join2);
@@ -44,6 +45,13 @@ public class IterUtilTest {
 		Assert.assertEquals("1:2:3:4", join);
 	}
 
+	@Test
+	public void joinWithNullTest() {
+		ArrayList<String> list = CollUtil.newArrayList("1", null, "3", "4");
+		String join = IterUtil.join(list.iterator(), ":", String::valueOf);
+		Assert.assertEquals("1:null:3:4", join);
+	}
+
 	@Test
 	public void testToListMap() {
 		Map<String, List<String>> expectedMap = new HashMap<>();

hutool-core/src/test/java/cn/hutool/core/io/ClassPathResourceTest.java

@@ -1,30 +1,30 @@
 package cn.hutool.core.io;
 
+import cn.hutool.core.io.resource.ClassPathResource;
+import cn.hutool.core.util.StrUtil;
+import org.junit.Assert;
+import org.junit.Test;
+
 import java.io.IOException;
 import java.util.Properties;
 
-import org.junit.Assert;
-import org.junit.Test;
-
-import cn.hutool.core.io.resource.ClassPathResource;
-import cn.hutool.core.util.StrUtil;
-
 /**
  * ClassPath资源读取测试
- * @author Looly
  *
+ * @author Looly
  */
 public class ClassPathResourceTest {
 
 	@Test
-	public void readStringTest() throws IOException{
+	public void readStringTest() {
 		ClassPathResource resource = new ClassPathResource("test.properties");
 		String content = resource.readUtf8Str();
 		Assert.assertTrue(StrUtil.isNotEmpty(content));
 	}
 
 	@Test
-	public void readStringTest2() throws IOException{
+	public void readStringTest2() {
+		// 读取classpath根目录测试
 		ClassPathResource resource = new ClassPathResource("/");
 		String content = resource.readUtf8Str();
 		Assert.assertTrue(StrUtil.isNotEmpty(content));
@@ -41,7 +41,7 @@ public class ClassPathResourceTest {
 	}
 
 	@Test
-	public void readFromJarTest() throws IOException{
+	public void readFromJarTest() {
 		//测试读取junit的jar包下的LICENSE-junit.txt文件
 		final ClassPathResource resource = new ClassPathResource("LICENSE-junit.txt");
 

hutool-core/src/test/java/cn/hutool/core/text/StrJoinerTest.java

@@ -0,0 +1,30 @@
+package cn.hutool.core.text;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class StrJoinerTest {
+
+	@Test
+	public void joinIntArrayTest(){
+		int[] a = {1,2,3,4,5};
+		final StrJoiner append = StrJoiner.of(",").append(a);
+		Assert.assertEquals("1,2,3,4,5", append.toString());
+	}
+
+	@Test
+	public void joinEmptyTest(){
+		List<String> list = new ArrayList<>();
+		final StrJoiner append = StrJoiner.of(",").append(list);
+		Assert.assertEquals("", append.toString());
+	}
+
+	@Test
+	public void noJoinTest(){
+		final StrJoiner append = StrJoiner.of(",");
+		Assert.assertEquals("", append.toString());
+	}
+}