Java常用方法函数总结

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判断字符串为空的方法

public static boolean isNull(String... obj){                for(String s : obj){                      if(s == null || "".equals(s)){                     return true;                   }                }                return false;            }

判断一个字符是否包含在一个数组字符中

private boolean isInStringArray(String string, ArrayList<String> arrayList) {        for (String oneString : arrayList) {            if (string.equals(oneString)) {                return true;            }        }        return false;    }

android判断EditText输入的数字、中文还是字母方法

String txt = edInput.getText().toString();  Pattern p = Pattern.compile("[0-9]*");   Matcher m = p.matcher(txt);   if(m.matches() ){   Toast.makeText(Main.this,"输入的是数字", Toast.LENGTH_SHORT).show();   }   p=Pattern.compile("[a-zA-Z]");   m=p.matcher(txt);   if(m.matches()){   Toast.makeText(Main.this,"输入的是字母", Toast.LENGTH_SHORT).show();   }   p=Pattern.compile("[\u4e00-\u9fa5]");   m=p.matcher(txt);   if(m.matches()){   Toast.makeText(Main.this,"输入的是汉字", Toast.LENGTH_SHORT).show();   }

String txt = edInput.getText().toString();  Pattern p = Pattern.compile("[0-9]*");   Matcher m = p.matcher(txt);   if(m.matches() ){   Toast.makeText(Main.this,"输入的是数字", Toast.LENGTH_SHORT).show();   }   p=Pattern.compile("[a-zA-Z]");   m=p.matcher(txt);   if(m.matches()){   Toast.makeText(Main.this,"输入的是字母", Toast.LENGTH_SHORT).show();   }   p=Pattern.compile("[\u4e00-\u9fa5]");   m=p.matcher(txt);   if(m.matches()){   Toast.makeText(Main.this,"输入的是汉字", Toast.LENGTH_SHORT).show();   }

华为手机管家黑名单判定流程

public static byte[] imsiToKey(String imsi) {        if (imsi == null) {            return null;        }        int len = imsi.length();        int lenKey = len / 2 + 1;        boolean even = len % 2 != 0;        byte[] key = new byte[lenKey];        for (int i = 0; i < lenKey; i++) {            if (i == 0) {                key[0] = (byte) (0x00 + (imsi.charAt(0) - '0') * 16 + 9);            } else if (i == (lenKey - 1) && !even) {                key[i] = (byte) (0x00 + 0xF0 + (imsi.charAt(len - 1) - '0'));            } else {                key[i] = (byte) (0x00 + (imsi.charAt(i * 2) - '0') * 16 + (imsi.charAt(i * 2 - 1) - '0'));            }        }        MTKlog.i(TAG, "imsiToKey is : " + key.toString());        return key;    }

转16进制

public static String bytesToHexString(byte[] src) {        StringBuilder stringBuilder = new StringBuilder();        if (src == null || src.length <= 0) {            return null;        }        for (int i = 0; i < src.length; i++) {            int v = src[i] & 0xFF;            String hv = Integer.toHexString(v);            if (hv.length() < 2) {                stringBuilder.append(0);            }            stringBuilder.append(hv);        }        return stringBuilder.toString();    }

如何把 int、short 变量与 byte[] 的转换

private static byte[] intToByteArray(int data) {    return ByteBuffer.allocate(4).order(ByteOrder.LITTLE_ENDIAN).putInt(data).array();} private static byte[] shortToByteArray(short data) {    return ByteBuffer.allocate(2).order(ByteOrder.LITTLE_ENDIAN).putShort(data).array();}  private static short byteArrayToShort(byte[] b) {    return ByteBuffer.wrap(b).order(ByteOrder.LITTLE_ENDIAN).getShort();}     private static int byteArrayToInt(byte[] b) {    return ByteBuffer.wrap(b).order(ByteOrder.LITTLE_ENDIAN).getInt();}

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