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HomeDatabaseMysql TutorialOracle 10进制转换2进制

写了个Oracle转换函数,发现当数据为负数的时候,无法转换,因为业务前端入库的数据是32位,当JAVA进行有符号转换为INT类型的时候

写了个Oracle转换函数,发现当数据为负数的时候,无法转换,,因为业务前端入库的数据是32位,当JAVA进行有符号转换为INT类型的时候,会产生负数,而我要再次转换为二进制进行位的判断,网上找了好多,都不能做有符号数字的转换,因此按照负数的二进制表示法重新写了个函数:

负数的二进制方法的表示方法:例如 -5  
第一步:首先要把5变成101的二进制形式
第二步:再者就是安位取反,(形成前面全是1)010
第三步:在最后加1 形成:11111111 11111111 11111111 11111011

CREATE OR REPLACE FUNCTION NUMBER_2_BIT(V_NUM NUMBER) RETURN VARCHAR IS
  V_RTN VARCHAR(2000);
  V_N1  NUMBER;
  V_N2  NUMBER;
BEGIN
  V_N1 := ABS(V_NUM);
  --如果为正数
  IF SIGN(V_NUM) > 0 THEN
    LOOP
      V_N2  := MOD(V_N1, 2);
      V_N1  := ABS(TRUNC(V_N1 / 2));
      V_RTN := TO_CHAR(V_N2) || V_RTN;
      EXIT WHEN V_N1 = 0;
    END LOOP;
   
    --dbms_output.put_line('正数结果'||V_RTN);
    
    --补全32位高位0
    SELECT lpad(V_RTN,32,0)
    INTO   V_RTN
    FROM dual;
   
     --dbms_output.put_line('正数补全结果'||V_RTN);
   
  ELSE
    --转换为二进制同时按位取反
    LOOP
      V_N2 := MOD(V_N1, 2);
      IF V_N2 = 1 THEN
        V_N2 := 0;
      ELSIF V_N2 = 0 THEN
        V_N2 := 1;
      END IF;
      V_N1  := ABS(TRUNC(V_N1 / 2));
      V_RTN := TO_CHAR(V_N2) || V_RTN;
      EXIT WHEN V_N1 = 0;
    END LOOP;
   
    --dbms_output.put_line('负数结果'||V_RTN);
   
    --补全32位高位1
    SELECT lpad(V_RTN,32,1)
    INTO   V_RTN
    FROM dual;
   
    --dbms_output.put_line('负数补全1结果'||V_RTN);
   
    --二进制转换为10机制,同时+1
    SELECT SUM(data1) + 1
    INTO V_N1
      FROM (SELECT substr(V_RTN, rownum, 1) * power(2, length(V_RTN) - rownum) data1
              FROM dual
            CONNECT BY rownum    
    -- dbms_output.put_line('转换为十进制数结果'||V_RTN);
    
    ----转换为二进制
    LOOP
      V_N2 := MOD(V_N1, 2);
      V_N1  := ABS(TRUNC(V_N1 / 2));
      V_RTN := TO_CHAR(V_N2) || V_RTN;
      EXIT WHEN V_N1 = 0;
    END LOOP;
   
    --dbms_output.put_line('负数转换结果'||V_RTN);
   
    --补全32位高位0
    SELECT lpad(V_RTN,32,0)
    INTO   V_RTN
    FROM dual;
   
    --dbms_output.put_line('负数补全0结果'||V_RTN);
   
  END IF;

  RETURN V_RTN;
END;

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