Java字符串转换成算术表达式计算并输出结果，java算术,package cn.a

Java字符串转换成算术表达式计算并输出结果，java算术,package cn.a

package cn.anycall.test;  import java.math.BigDecimal;  public class TestSHU {      /**        * 两个字符类型的小数进行相加为a+b;        *         * @param a        * @param b        * @return        */        public static String addBigDecimal(String a, String b) {             double a1 = Double.parseDouble(a);             double b1 = Double.parseDouble(b);             BigDecimal a2 = BigDecimal.valueOf(a1);             BigDecimal b2 = BigDecimal.valueOf(b1);             BigDecimal c2 = a2.add(b2);             String c1 = c2 + "";             return c1;         }        /**        * 两个字符类型的小数进行相减为a-b;        *         * @param a        * @param b        * @return        */        public static String reduceBigDecimal(String a, String b) {             double a1 = Double.parseDouble(a);             double b1 = Double.parseDouble(b);             BigDecimal a2 = BigDecimal.valueOf(a1);             BigDecimal b2 = BigDecimal.valueOf(b1);             BigDecimal c2 = a2.subtract(b2);             String c1 = c2 + "";             return c1;         }        /**        * 两个字符类型的数相乘 a*b=c；        *         * @param a        * @param b        * @return        */        public static String multipliedString(String a, String b) {             double a1 = Double.parseDouble(a);             double b1 = Double.parseDouble(b);             BigDecimal a2 = BigDecimal.valueOf(a1);             BigDecimal b2 = BigDecimal.valueOf(b1);             BigDecimal c2 = a2.multiply(b2);             String c1 = c2 + "";             return c1;         }        /**        * 两个字符类型的数相除 a/b=c；        *         * @param a        * @param b        * @return        */        public static String divideString(String a, String b) {             double a1 = Double.parseDouble(a);             double b1 = Double.parseDouble(b);             BigDecimal a2 = BigDecimal.valueOf(a1);             BigDecimal b2 = BigDecimal.valueOf(b1);             BigDecimal c2 = a2.divide(b2,a2.scale());             String c1 = c2 + "";             return c1;         }        public static String yunsuanjibie(String s) {          String r = "";          int p = 0;          for (int i = 0; i < s.length(); i++) {              if (s.charAt(i) == '+' || s.charAt(i) == '-' || s.charAt(i) == '*'                      || s.charAt(i) == '/') {                  p++;              }          }          String k[] = new String[2 * p + 1];          int k1 = 0;          int first = 0;          for (int i = 0; i < s.length(); i++) {              if (s.charAt(i) == '+' || s.charAt(i) == '-' || s.charAt(i) == '*'                      || s.charAt(i) == '/') {                  k[k1] = s.substring(first, i);                  k1++;                  k[k1] = "" + s.charAt(i);                  k1++;                  first = i + 1;              }          }          k[k1] = s.substring(first, s.length());          int kp = p;          while (kp > 0) {              for (int i = 0; i < k.length; i++) {                  if (k[i].equals("*") || k[i].equals("/")) {                      int l;                      for (l = i - 1; l > -1; l--) {                          if (!(k[l].equals("p")))                              break;                      }                      int q;                      for (q = i + 1; q < k.length; q++) {                          if (!(k[l].equals("p")))                              break;                      }                      if (k[i].equals("*")) {                          k[i] = ""+ multipliedString(k[l],k[q]);                          k[l] = "p";                          k[q] = "p";                          kp--;                      } else {                          k[i] = ""+divideString(k[l],k[q]);                          k[l] = "p";                          k[q] = "p";                          kp--;                      }                      break;                  }              }              for (int i = 0; i < 2 * p + 1; i++) {                  if (k[i].equals("+") || k[i].equals("-")) {                      int l;                      for (l = i - 1; l > -1; l--) {                          if (!(k[l].equals("p")))                              break;                      }                      int q;                      for (q = i + 1; q < k.length; q++) {                          if (!(k[q].equals("p")))                              break;                      }                      if (k[i].equals("+")) {                          k[i] = ""+addBigDecimal(k[l],k[q]);                          k[l] = "p";                          k[q] = "p";                          kp--;                      } else {                          k[i] = ""+reduceBigDecimal(k[l],k[q]);                          k[l] = "p";                          k[q] = "p";                          kp--;                      }                      break;                  }              }              for (int i = 0; i < k.length; i++) {                  if (!(k[i].equals("p"))) {                      r = k[i];                      break;                  }              }          }          return r;      }      public static void sizeyunsuan(String s) {          while (true) {              int first = 0;              int last = 0;              for (int i = 0; i < s.length(); i++) {                  if (s.charAt(i) == '(')                      first = i;                  if (s.charAt(i) == ')') {                      last = i;                      break;                  }              }              if (last == 0) {                  System.out.println(yunsuanjibie(s));                  return;              } else {                  String s1 = s.substring(0, first);                  String s2 = s.substring(first + 1, last);                  String s3 = s.substring(last + 1, s.length());                  s = s1 + yunsuanjibie(s2) + s3;              }          }      }      public static void main(String[] args) {          String s = "1.4+2*32/(3-2.1)";          sizeyunsuan(s);      }  }