diff --git a/comm/src/main/java/cn/yizems/util/ktx/comm/java/NullUtil.java b/comm/src/main/java/cn/yizems/util/ktx/comm/java/NullUtil.java
new file mode 100644
index 0000000..ce46c6f
--- /dev/null
+++ b/comm/src/main/java/cn/yizems/util/ktx/comm/java/NullUtil.java
@@ -0,0 +1,81 @@
+package cn.yizems.util.ktx.comm.java;
+
+public class NullUtil<T> {
+
+    protected T data;
+
+    public NullUtil(T data) {
+        this.data = data;
+    }
+
+    public static <T> NullUtil<T> of(T t) {
+        return new NullUtil<T>(t);
+    }
+
+
+    public T get() {
+        return data;
+    }
+
+    public boolean isNull(){
+        return data == null;
+    }
+
+    public <R> NullUtil<R> map(Mapper<T, R> mapper) {
+        if (data == null) {
+            return new NullUtil<R>(null);
+        }
+        return new NullUtil<R>(mapper.apply(data));
+    }
+
+    public T getOrElse(T defaultValue) {
+        if (data == null) {
+            return defaultValue;
+        }
+        return data;
+    }
+
+    public T getOrThrow() throws NullPointerException {
+        if (data == null) {
+            throw new NullPointerException("data is null");
+        }
+        return data;
+    }
+
+    public void onNull(EmptyConsumer consumer) {
+        if (data == null) {
+            consumer.accept();
+        }
+    }
+    public void notNull(NotNullConsumer<T> consumer) {
+        if (data != null) {
+            consumer.accept(data);
+        }
+    }
+
+    public interface Mapper<T, R> {
+        R apply(T t);
+    }
+
+    public interface NotNullConsumer<T> {
+        void accept(T t);
+    }
+
+    public interface EmptyConsumer {
+        void accept();
+    }
+
+    public StringNullUtil toStringUtil() {
+        if (data instanceof String) {
+            return new StringNullUtil((String) data);
+        }
+
+        if (data instanceof CharSequence) {
+            return new StringNullUtil(data.toString());
+        }
+        if (data == null) {
+            return new StringNullUtil(null);
+        }
+        return new StringNullUtil(data.toString());
+    }
+}
diff --git a/comm/src/main/java/cn/yizems/util/ktx/comm/java/StringNullUtil.java b/comm/src/main/java/cn/yizems/util/ktx/comm/java/StringNullUtil.java
new file mode 100644
index 0000000..a884dd9
--- /dev/null
+++ b/comm/src/main/java/cn/yizems/util/ktx/comm/java/StringNullUtil.java
@@ -0,0 +1,211 @@
+package cn.yizems.util.ktx.comm.java;
+
+import java.util.Locale;
+
+public class StringNullUtil extends NullUtil<String> {
+
+    private boolean mutable = false;
+
+    public StringNullUtil(String data) {
+        super(data);
+    }
+
+    public StringNullUtil mutable() {
+        this.mutable = true;
+        return this;
+    }
+
+    public static StringNullUtil of(CharSequence t) {
+        if (t == null) {
+            return new StringNullUtil(null);
+        }
+        return new StringNullUtil(t.toString());
+    }
+
+    public boolean isNullOrEmpty() {
+        return data == null || data.length() == 0;
+    }
+
+    public boolean isNullOrBlank() {
+        return data == null || data.trim().length() == 0;
+    }
+
+    public StringNullUtil trim() {
+        if (data == null) {
+            return new StringNullUtil(null);
+        }
+        if (mutable) {
+            data = data.trim();
+            return this;
+        }
+        return new StringNullUtil(data.trim());
+    }
+
+    public StringNullUtil toUpperCase() {
+        if (data == null) {
+            return new StringNullUtil(null);
+        }
+        if (mutable) {
+            data = data.toUpperCase();
+            return this;
+        }
+        return new StringNullUtil(data.toUpperCase());
+    }
+
+    public StringNullUtil toLowerCase() {
+        if (data == null) {
+            return new StringNullUtil(null);
+        }
+        if (mutable) {
+            data = data.toLowerCase();
+            return this;
+        }
+        return new StringNullUtil(data.toLowerCase());
+    }
+
+    public StringNullUtil replace(CharSequence target, CharSequence replacement) {
+        if (data == null) {
+            return new StringNullUtil(null);
+        }
+        if (mutable) {
+            data = data.replace(target, replacement);
+            return this;
+        }
+        return new StringNullUtil(data.replace(target, replacement));
+    }
+
+    public StringNullUtil replaceAll(String regex, String replacement) {
+        if (data == null) {
+            return new StringNullUtil(null);
+        }
+        if (mutable) {
+            data = data.replaceAll(regex, replacement);
+            return this;
+        }
+        return new StringNullUtil(data.replaceAll(regex, replacement));
+    }
+
+    public int length() {
+        if (data == null) {
+            return 0;
+        }
+        return data.length();
+    }
+
+    public StringNullUtil substring(int beginIndex) {
+        if (data == null) {
+            return new StringNullUtil(null);
+        }
+        if (mutable) {
+            data = data.substring(beginIndex);
+            return this;
+        }
+        return new StringNullUtil(data.substring(beginIndex));
+    }
+
+    public int indexOf(String str) {
+        if (data == null) {
+            return -1;
+        }
+        return data.indexOf(str);
+    }
+
+    public int indexOf(String str, int fromIndex) {
+        if (data == null) {
+            return -1;
+        }
+        return data.indexOf(str, fromIndex);
+    }
+
+    public int lastIndexOf(String str) {
+        if (data == null) {
+            return -1;
+        }
+        return data.lastIndexOf(str);
+    }
+
+    public int lastIndexOf(String str, int fromIndex) {
+        if (data == null) {
+            return -1;
+        }
+        return data.lastIndexOf(str, fromIndex);
+    }
+
+    public StringNullUtil format(Object... args) {
+        if (data == null) {
+            return new StringNullUtil(null);
+        }
+        if (mutable) {
+            data = String.format(data, args);
+            return this;
+        }
+        return new StringNullUtil(String.format(data, args));
+    }
+
+    public StringNullUtil format(String locale, Object... args) {
+        if (data == null) {
+            return new StringNullUtil(null);
+        }
+        if (mutable) {
+            data = String.format(locale, data, args);
+            return this;
+        }
+        return new StringNullUtil(String.format(locale, data, args));
+    }
+
+    public StringNullUtil format(Locale locale, String format, Object... args) {
+        if (data == null) {
+            return new StringNullUtil(null);
+        }
+        if (mutable) {
+            data = String.format(locale, data, args);
+            return this;
+        }
+        return new StringNullUtil(String.format(locale, data, args));
+    }
+
+    public static StringNullUtil valueOf(Boolean b) {
+        if (b == null) return new StringNullUtil(null);
+        return new StringNullUtil(String.valueOf(b));
+    }
+
+    public static StringNullUtil valueOf(char c) {
+        return new StringNullUtil(String.valueOf(c));
+    }
+
+    public static StringNullUtil valueOf(char[] data) {
+        if (data == null) return new StringNullUtil(null);
+        return new StringNullUtil(String.valueOf(data));
+    }
+
+    public static StringNullUtil valueOf(char[] data, int offset, int count) {
+        if (data == null) return new StringNullUtil(null);
+        return new StringNullUtil(String.valueOf(data, offset, count));
+    }
+
+    public static StringNullUtil valueOf(Double d) {
+        if (d == null) return new StringNullUtil(null);
+        return new StringNullUtil(String.valueOf(d));
+    }
+
+    public static StringNullUtil valueOf(Float f) {
+        if (f == null) return new StringNullUtil(null);
+        return new StringNullUtil(String.valueOf(f));
+    }
+
+    public static StringNullUtil valueOf(Integer i) {
+        if (i == null) return new StringNullUtil(null);
+        return new StringNullUtil(String.valueOf(i));
+    }
+
+    public static StringNullUtil valueOf(Long l) {
+        if (l == null) return new StringNullUtil(null);
+        return new StringNullUtil(String.valueOf(l));
+    }
+
+    public static StringNullUtil valueOf(Object obj) {
+        if (obj == null) return new StringNullUtil(null);
+        return new StringNullUtil(String.valueOf(obj));
+    }
+
+}