1、数据类型转换类

1.1、字节数组转为布尔数组

  1.  // 101110101   转为布尔数组
  2. static public boolean[] toBitsArray(byte[] bytes, int bitCount) {
  3.     boolean[] dst = new boolean[bitCount];
  4.     for (int i = 0; i < dst.length; i++) {
  5.         dst[i] = (bytes[i / 8] & (1 << (i % 8))) != 0;
  6.     }
  7.     return dst;
  8. }

1.2、字节数组转为浮点型

  1. public static float toFloatLittleEndian(byte[] bytes) {
  2.         return Float.intBitsToFloat(
  3.                 ((bytes[0] & 0xff) << 8) |
  4.                         (bytes[1] & 0xff) |
  5.                         ((bytes[2] & 0xff) << 24) |
  6.                         ((bytes[3] & 0xff) << 16));
  7.     }
  9.     public static float toFloatBigEndian(byte[] bytes) {
  10.         return Float.intBitsToFloat(
  11.                 ((bytes[0] & 0xff) << 24) |
  12.                         ((bytes[1] & 0xff) << 16) |
  13.                         ((bytes[2] & 0xff) << 8) |
  14.                         ((bytes[3] & 0xff)));
  15.     }
  17.     public static float toFloatBigEndianBySwap(byte[] bytes) {
  18.         return Float.intBitsToFloat(
  19.                 ((bytes[0] & 0xff) << 16) |
  20.                         ((bytes[1] & 0xff) << 24) |
  21.                         (bytes[2] & 0xff) |
  22.                         ((bytes[3] & 0xff) << 8));
  23.     }
  25.     public static float toFloatLittleEndianBySwap(byte[] bytes) {
  26.         return Float.intBitsToFloat(
  27.                 (bytes[0] & 0xff) |
  28.                         (bytes[1] & 0xff) << 8 |
  29.                         (bytes[2] & 0xff) << 16 |
  30.                         (bytes[3] & 0xff) << 24);
  31.     }

1.3、字节数组转为整数

  1. //两个字节不带符合
  2. public static int byteArrayToInt(byte[] data) {
  3.         return (data[0] & 255) << 8 | data[1] & 255;
  4.     }
  6. // 两个字节 带符号
  7.     public static short byteArrayToShort(byte[] data) {
  8.         return (short) ((data[0] & 255) << 8 | data[1] & 255);
  9.     }

2、枚举类示例

  1. public enum FunctionCode {
  3.     /**
  4.      * 读线圈状态
  5.      */
  6.     READ_COIL_STATUS("0x01") {
  7.         @Override
  8.         public SimpleModbusRequest buildRequest(int offset, int num) {
  9.             return new ReadCoilsRequest(offset, num);
  10.         }
  11.     },
  12.     /**
  13.      * 未知功能码
  14.      */
  15.     UNKNOWN("0x00") {
  16.         @Override
  17.         public SimpleModbusRequest buildRequest(int offset, int num) {
  18.             return null;
  19.         }
  20.     };
  22.     private final String code;
  24.     public String getCode() {
  25.         return code;
  26.     }
  28.     public static FunctionCode isCode(String code) {
  29.         Class<FunctionCode> codeClass = FunctionCode.class;
  30.         FunctionCode functionCode = UNKNOWN;
  31.         try {
  32.             for (FunctionCode ele : codeClass.getEnumConstants()) {
  33.                 if (codeClass.getMethod("getCode").invoke(ele).equals(code)) {
  34.                     functionCode = ele;
  35.                     break;
  36.                 }
  37.             }
  38.         } catch (Exception e) {
  39.             e.printStackTrace();
  40.         }
  41.         return functionCode;
  42.     }
  44.     FunctionCode(String code) {
  45.         this.code = code;
  46.     }
  48.     public abstract SimpleModbusRequest buildRequest(int offset, int num);
  49. }

3、打印进度条

  1. Random random = new Random();
  2. for (int i = 0; i <=100 ; i++) {
  3.     Thread.sleep(random.nextInt(100));
  4.     System.out.print("\r"+i+"%");
  5. }

4、CompletableFuture

参考

6、Map API

  1. map.computeIfAbsent(key, k -> new ArrayList<>()）

7、反射

7.1、给属性赋值,获取值

  1. PropertyDescriptor pd = new PropertyDescriptor(name, cls);
  2. Method setMethod = pd.getWriteMethod();
  3. setMethod.invoke(object, value);
  6. Method getMethod=pd.getReadMethod();
  7. getMethod.invoke(object)
  9.  // apache 工具包 beanutils
  10. BeanUtils.setProperty(ipNetToMediaEntry, name, variable.toString());