finished util: StringHelper

src/main/java/util/ByteHelper.java

@@ -53,6 +53,12 @@ public class ByteHelper {
         // System.arraycopy(buffer,startInt,firstbyte,0,firstbyte.length);
         // return firstbyte[0];
     }
+    public static byte getFirstByte(byte[] buffer, int startInt) throws ByteHelperException {
+        if(startInt >= buffer.length || startInt < 0){
+            throw new ByteHelperException("buffer out of bounds");
+        }
+        return buffer[startInt];
+    }
 
     /**
      * 从byte[]数组指定开始位置获取长度为len的字节数组
@@ -93,6 +99,11 @@ public class ByteHelper {
         System.arraycopy(buffer,startInt,lenbytes,0,len);
         return lenbytes;
     }
+    public static byte[] getLenBytes(byte[] buffer, int startInt,int len){
+        byte[] lenbytes=new byte[len];
+        System.arraycopy(buffer,startInt,lenbytes,0,len);
+        return lenbytes;
+    }
 
     /**
      * 无符号int转byte[]

src/main/java/util/StringHelper.java

@@ -1,5 +1,10 @@
 package util;
 
+import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.LinkedList;
+
 /*
  * @Author: Wang Feng
  * @Description:
@@ -7,8 +12,27 @@ package util;
  * @Date: 11:27 2021/3/10
  * @Copyright: MIN-Group；国家重大科技基础设施——未来网络北大实验室；深圳市信息论与未来网络重点实验室
  */
+
 public class StringHelper {
 
+    private static byte toHexChar(byte n){
+        return (byte) "0123456789ABCDEF".toCharArray()[n&0xf];
+    }
+
+    private static byte fromHexToChar(byte c){
+        byte res;
+        if((c>='0') && (c<='9')){
+            res= (byte) (c-'0');
+        }else if((c>='a') && (c<='f')){
+            res= (byte) (c-'a'+10);
+        }else if((c>='A') && (c<='F')){
+            res= (byte) (c-'A'+10);
+        }else {
+            res=100;
+        }
+        return res;
+    }
+
     /**
      * 对字符串实施百分号编码
      * // @Description:
@@ -24,7 +48,28 @@ public class StringHelper {
      * @return
      */
     public static String escape(String str){
-        return "";
+        byte[] strBytes=str.getBytes(StandardCharsets.UTF_8);
+        int len=strBytes.length;
+        ByteBuffer byteBuffer = null;
+        int index=0;
+        for(int i=0;i<len;i++){
+            byte ch=strBytes[i];
+            if((ch>='a'&&ch<='z')||
+                    (ch>='A'&&ch<='Z')||
+                    (ch>='0'&&ch<='9')||
+                    ch=='-'||ch=='.'||ch=='_'||ch=='~'){
+                byteBuffer.put(index,ch);
+                index++;
+            }else{
+                byteBuffer.put(index,(byte)'%');
+                index++;
+                byteBuffer.put(index,toHexChar((byte) ((ch & 0xf0) >> 4)));
+                index++;
+                byteBuffer.put(index,toHexChar((byte) (ch & 0xf)));
+                index++;
+            }
+        }
+        return new String(byteBuffer.array());
     }
 
     /**
@@ -33,7 +78,31 @@ public class StringHelper {
      * @return
      */
     public static String unescape(String str){
-        return "";
+        byte[] strBytes=str.getBytes(StandardCharsets.UTF_8);
+        int len=strBytes.length;
+        byte[] resBytes=new byte[len];
+        int index=0;
+        for (int i = 0; i < len; i++) {
+            byte ch=strBytes[i];
+            if((ch=='%')&&(i+2<len)){
+                byte high=fromHexToChar(strBytes[i+1]);
+                byte low=fromHexToChar(strBytes[i+2]);
+
+                // 如果是无效的hex字符，则保持原样输出
+                if((high==100)||(low==100)){
+                    resBytes[index]=ch;
+                    index++;
+                }else {
+                    resBytes[index]= (byte) ((high << 4) | low);
+                    index++;
+                }
+                i+=2;
+            }else{
+                resBytes[index]=ch;
+                index++;
+            }
+        }
+        return new String(ByteHelper.getLenBytes(resBytes,0,index));
     }