库位码排序优化

库位码就是形如( A01-002-004 ) 的数据，前面一个大写字母，后面跟着一个整数。然后就是用 - 隔开再跟整数。上面说到的整数前面都可能有n个0填充 (排序时应该忽略)

比较规则：先比较第一个字母大小，然后依次比较后面的整数。

库位码比较器 (优化思路：1、避免产生新的字符串对象。2、不需要解析为整数) （下面程序解决了脏数据报错的问题）

package com.example.demo.bean;
import java.util.Comparator;
public class StoreLocalCodeComparator implements Comparator {
public char splitChar;
public StoreLocalCodeComparator(char splitChar) {
this.splitChar = splitChar;
}
public static Comparator compatibleNull(boolean first, char splitChar) {
if(first) {
return Comparator.nullsFirst(new StoreLocalCodeComparator(splitChar));
} else {
return Comparator.nullsLast(new StoreLocalCodeComparator(splitChar));
}
}
/**
* @param s1 非0开始的位置
* @param e1 split 的位置
* @param one
* @param s2 非0开始的位置
* @param e2 split 的位置
* @param two
* @return
*/
private int partCompare(int s1, int e1, String one,
int s2, int e2, String two) {
int i1 = e1 - s1;
int i2 = e2 - s2;
int i = i1 - i2;
if(i == 0) {
while(s1 < e1) {
int t = one.charAt(s1) - two.charAt(s2);
if(t != 0) {
return t;
}
s1++;
s2++;
}
return 0;
}
return i;
}
private int findSplitChar(int start, String s) {
int size = s.length();
for(;start ) {
if(s.charAt(start) == splitChar) {
return start;
}
}
return start;
}
private int findFirstNoZeroNumIndex(int start, String s) {
int size = s.length();
for(;start ) {
char c = s.charAt(start);
if(c > '0' && c <= '9') {
break;
}
}
return start;
}
@Override
public int compare(String one, String two) {
int l1 = one.length(), l2 = two.length();
if(l1 == 0 || l2 == 0) {
return l1 - l2;
}
int c = one.charAt(0) - two.charAt(0);
int s1, s2, e1 = 1, e2 = 1;
boolean end = false;
while(c == 0 && !end) {
s1 = findFirstNoZeroNumIndex(e1, one);
s2 = findFirstNoZeroNumIndex(e2, two);
if(s1 == l1 || s2 == l2) {
end = true;
}
e1 = findSplitChar(s1, one);
e2 = findSplitChar(s2, two);
c = partCompare(s1, e1, one, s2, e2, two);
}
return c;
}
}

测试：（经过测试1百万的数据在内存中排序在2秒内，测试程序如下，感兴趣的可以测试一下）

package com.example.demo;
import com.example.demo.bean.StoreLocalCodeComparator;
import org.junit.Test;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.concurrent.ThreadLocalRandom;
public class SortTest {
public List initData(int size, boolean hasDirty) {
List list = new ArrayList<>();
for(int i = 0;i ) {
list.add(randomCreateData(100, hasDirty));
}
return list;
}
private String dirtyData(int maxSize) {
ThreadLocalRandom tlr = ThreadLocalRandom.current();
int f = tlr.nextInt(2, maxSize);
int i = tlr.nextInt(0, 6);
if(i == 0) {
return null;
} else if(i == 1) {
return "";
} else if(i == 2) {
return " ";
} else if(i == 3) {
String s = "";
for(int j = 0;j ) {
s += " ";
}
return s;
} else if(i == 4) {
return "" + (char)tlr.nextInt(33, 127);
} else {
String s = "";
for (int j = 0; j ) {
s += (char) tlr.nextInt(33, 127);
}
return s;
}
}
private String randomCreateData(int numSize, boolean hasDirty) {
ThreadLocalRandom tlr = ThreadLocalRandom.current();
if(hasDirty && tlr.nextInt(100000) == 0) {
return dirtyData(15);
}
StringBuilder sb = new StringBuilder();
sb.append((char) tlr.nextInt(65, 91));
addZero(sb, 3);
sb.append(tlr.nextInt(1, numSize));
sb.append('-');
addZero(sb, 3);
sb.append(tlr.nextInt(1, numSize));
sb.append('-');
addZero(sb, 3);
sb.append(tlr.nextInt(1, numSize));
return sb.toString();
}
/**
* @param sb
* @param maxSize
*/
private void addZero(StringBuilder sb, int maxSize) {
ThreadLocalRandom tlr = ThreadLocalRandom.current();
int size = tlr.nextInt(0, maxSize);
for(int i = 0;i <= size;i++) {
sb.append('0');
}
}
private void writeToFile(List list, String filePath) throws IOException{
try(FileWriter fw = new FileWriter(filePath)) {
for (int i = 0; i ) {
fw.write(list.get(i) + "\n");
}
}
}
/**
* 将一百万数据排序后导出检查
* @throws IOException
*/
@Test
public void test2() throws IOException {
Comparator comparator = StoreLocalCodeComparator.compatibleNull(true, '-');
List list = initData(1000000, false);
long start = System.currentTimeMillis();
list.sort(comparator);
System.out.println("耗时: " + (System.currentTimeMillis() - start));
String path = System.getProperty("java.io.tmpdir") + "test.txt";
writeToFile(list, path);
System.out.println(path);
}
/**
* 连续10次测试一百万数据。
* @throws IOException
*/
@Test
public void test() throws IOException {
Comparator comparator = StoreLocalCodeComparator.compatibleNull(true, '-');
List list = null;
for(int i = 0;i <10;i++) {
try {
list = initData(1000000, true);
long start = System.currentTimeMillis();
list.sort(comparator);
System.out.println("耗时: " + (System.currentTimeMillis() - start));
} catch (Exception e) {
String path = System.getProperty("java.io.tmpdir") + "current_error.txt";
writeToFile(list, path);
System.out.println(path);
e.printStackTrace();
}
}
//通过前面50条数据校验
int size = Math.min(50, list.size());
for(int i = 0;i ) {
System.out.println(list.get(i));
}
}
}