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ArrangementTest
This commit is contained in:
Looly
parent
bad0c4c982
commit
6cbdf89fe6
@ -16,8 +16,6 @@
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package cn.hutool.v7.core.math;
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import cn.hutool.v7.core.array.ArrayUtil;
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import java.io.Serial;
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import java.io.Serializable;
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import java.util.*;
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@ -74,7 +72,7 @@ public class Arrangement implements Serializable {
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long result = 1;
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// 从 n 到 n-m+1 逐个乘
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for (int i = 0; i < m; i++) {
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long next = result * (n - i);
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final long next = result * (n - i);
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// 溢出检测
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if (next < result) {
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throw new ArithmeticException("Overflow computing A(" + n + "," + m + ")");
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@ -149,11 +147,11 @@ public class Arrangement implements Serializable {
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return Collections.singletonList(new String[0]);
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}
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long estimated = count(datas.length, m);
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int capacity = estimated > Integer.MAX_VALUE ? Integer.MAX_VALUE : (int) estimated;
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final long estimated = count(datas.length, m);
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final int capacity = estimated > Integer.MAX_VALUE ? Integer.MAX_VALUE : (int) estimated;
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List<String[]> result = new ArrayList<>(capacity);
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boolean[] visited = new boolean[datas.length];
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final List<String[]> result = new ArrayList<>(capacity);
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final boolean[] visited = new boolean[datas.length];
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dfs(new String[m], 0, visited, result);
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return result;
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}
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@ -194,7 +192,7 @@ public class Arrangement implements Serializable {
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* @param m 选择的元素个数
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* @return 排列迭代器
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*/
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public Iterable<String[]> iterate(int m) {
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public Iterable<String[]> iterate(final int m) {
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return () -> new ArrangementIterator(datas, m);
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}
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@ -208,10 +206,18 @@ public class Arrangement implements Serializable {
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private final String[] datas;
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private final int m;
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private final int n;
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private final boolean[] visited;
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private final String[] buffer;
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private final Deque<Integer> stack = new ArrayDeque<>();
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boolean end = false;
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// 每一层记录当前尝试的下标，-1表示还未尝试
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private final int[] indices;
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private int depth;
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private boolean end;
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// 预取下一个元素
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private String[] nextItem;
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private boolean nextPrepared;
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/**
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* 构造函数
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@ -219,62 +225,137 @@ public class Arrangement implements Serializable {
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* @param datas 数据数组
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* @param m 选择的元素个数
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*/
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ArrangementIterator(String[] datas, int m) {
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ArrangementIterator(final String[] datas, final int m) {
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this.datas = datas;
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this.m = m;
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this.visited = new boolean[datas.length];
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this.buffer = new String[m];
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// 初始化 dfs 栈
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stack.push(0);
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this.n = datas.length;
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this.visited = new boolean[n];
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this.nextItem = null;
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this.nextPrepared = false;
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if (m < 0 || m > n) {
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// 无效或无解，直接结束
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this.indices = new int[Math.max(1, m)];
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this.buffer = new String[Math.max(1, m)];
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this.depth = -1;
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this.end = true;
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} else if (m == 0) {
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// m == 0: 只返回一个空数组
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this.indices = new int[0];
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this.buffer = new String[0];
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this.depth = 0;
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this.end = false;
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} else {
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this.indices = new int[m];
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Arrays.fill(this.indices, -1);
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this.buffer = new String[m];
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this.depth = 0;
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this.end = false;
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}
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}
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@Override
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public boolean hasNext() {
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return !end;
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if (end) {
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return false;
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}
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if (nextPrepared) {
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return nextItem != null;
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}
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prepareNext();
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return nextItem != null;
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}
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@Override
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public String[] next() {
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while (!stack.isEmpty()) {
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int depth = stack.size() - 1;
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if (end && !nextPrepared) {
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throw new NoSuchElementException();
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}
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if (!nextPrepared) {
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prepareNext();
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}
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if (nextItem == null) {
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throw new NoSuchElementException();
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}
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final String[] ret = nextItem;
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// 清除预取缓存，下一次需要重新准备
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nextItem = null;
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nextPrepared = false;
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// 如果m == 0，该项是唯一项，迭代结束
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if (m == 0) {
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end = true;
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}
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return ret;
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}
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int idx = stack.pop();
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if (idx >= datas.length) {
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// 这一层遍历结束
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if (!stack.isEmpty()) {
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int prev = stack.pop();
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stack.push(prev + 1);
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/**
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* 将状态推进到下一个可返回的排列并把它放入 nextItem。
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* 如果无更多排列，则将 end=true 并把 nextItem 置为 null。
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*/
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private void prepareNext() {
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// 已经准备过或已结束
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if (nextPrepared || end) {
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nextPrepared = true;
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return;
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}
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// special-case m == 0
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if (m == 0) {
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nextItem = new String[0];
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nextPrepared = true;
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// do not set end here; end will be set after returning this element in next()
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return;
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}
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// 非递归模拟DFS，直到找到一个可返回的排列或穷尽
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while (depth >= 0) {
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final int start = indices[depth] + 1;
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boolean found = false;
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for (int i = start; i < n; i++) {
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if (!visited[i]) {
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// 如果当前层之前有选过一个元素，要先取消之前选中的 visited
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if (indices[depth] != -1) {
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visited[indices[depth]] = false;
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}
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indices[depth] = i;
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visited[i] = true;
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buffer[depth] = datas[i];
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found = true;
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break;
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}
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}
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if (!found) {
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// 本层没有可用元素，回溯
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if (indices[depth] != -1) {
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visited[indices[depth]] = false;
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indices[depth] = -1;
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}
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depth--;
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continue;
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}
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// 如果该元素未使用
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if (!visited[idx]) {
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visited[idx] = true;
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buffer[depth] = datas[idx];
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if (depth == m - 1) {
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// 输出一个排列
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visited[idx] = false;
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// 下一次从 idx+1 继续
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stack.push(idx + 1);
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return Arrays.copyOf(buffer, m);
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} else {
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// 继续下一层
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stack.push(idx + 1); // 当前层下一个起点
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stack.push(0); // 下一层起点
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continue;
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// 若已达到输出深度，准备输出（但不抛出）
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if (depth == m - 1) {
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nextItem = Arrays.copyOf(buffer, m);
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// 取消当前visited，为下一次在同一层寻找下一个候选做准备
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visited[indices[depth]] = false;
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// 保持 depth 不变（下一次 prepare 会从 indices[depth]+1 开始寻找）
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nextPrepared = true;
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return;
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} else {
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// 向下一层深入：初始化下一层为-1并继续循环
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depth++;
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if (depth < m) {
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indices[depth] = -1;
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}
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}
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// 已访问则跳过
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stack.push(idx + 1);
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}
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// 若循环结束，说明已经穷尽所有可能
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end = true;
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return null;
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nextItem = null;
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nextPrepared = true;
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}
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}
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@ -286,7 +367,7 @@ public class Arrangement implements Serializable {
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* @param visited 标记数组，记录哪些索引已经被使用了
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* @param result 结果集
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*/
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private void dfs(String[] current, int depth, boolean[] visited, List<String[]> result) {
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private void dfs(final String[] current, final int depth, final boolean[] visited, final List<String[]> result) {
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if (depth == current.length) {
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result.add(Arrays.copyOf(current, current.length));
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return;
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@ -20,6 +20,7 @@ import cn.hutool.v7.core.lang.Console;
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import org.junit.jupiter.api.Disabled;
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import org.junit.jupiter.api.Test;
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import java.util.ArrayList;
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import java.util.List;
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import static org.junit.jupiter.api.Assertions.*;
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@ -152,4 +153,51 @@ public class ArrangementTest {
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assertArrayEquals(new String[]{"1", "2"}, all.get(3));
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assertArrayEquals(new String[]{"1", "2", "3"}, all.get(9));
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}
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// ----------------------------------------------------
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// 迭代器测试
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// ----------------------------------------------------
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@Test
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public void iteratorTest() {
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final Arrangement arrangement = new Arrangement(new String[]{"1", "2", "3"});
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// 测试 m=2 的情况
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final List<String[]> iterResult = new ArrayList<>();
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for (final String[] perm : arrangement.iterate(2)) {
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iterResult.add(perm);
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}
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assertEquals(6, iterResult.size());
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assertArrayEquals(new String[]{"1", "2"}, iterResult.get(0));
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assertArrayEquals(new String[]{"1", "3"}, iterResult.get(1));
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assertArrayEquals(new String[]{"2", "1"}, iterResult.get(2));
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assertArrayEquals(new String[]{"2", "3"}, iterResult.get(3));
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assertArrayEquals(new String[]{"3", "1"}, iterResult.get(4));
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assertArrayEquals(new String[]{"3", "2"}, iterResult.get(5));
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}
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@Test
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public void iteratorFullTest() {
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final Arrangement arrangement = new Arrangement(new String[]{"1", "2", "3"});
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// 测试全排列的情况
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final List<String[]> iterResult = new ArrayList<>();
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for (final String[] perm : arrangement.iterate(3)) {
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iterResult.add(perm);
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}
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assertEquals(6, iterResult.size());
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}
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@Test
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public void iteratorBoundaryTest() {
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final Arrangement arrangement = new Arrangement(new String[]{"1", "2", "3"});
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// 测试 m > n 的情况
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final List<String[]> iterResult = new ArrayList<>();
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for (final String[] perm : arrangement.iterate(5)) {
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iterResult.add(perm);
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}
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assertTrue(iterResult.isEmpty());
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}
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}
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@ -133,7 +133,7 @@ public class Excel03SaxReader implements HSSFListener, ExcelSaxReader<Excel03Sax
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* @throws POIException IO异常包装
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*/
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public Excel03SaxReader read(final POIFSFileSystem fs, final String idOrRidOrSheetName) throws POIException {
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this.sheetIndex = getSheetIndex(idOrRidOrSheetName);
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initSheetIndexOrSheetName(idOrRidOrSheetName);
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formatListener = new FormatTrackingHSSFListener(new MissingRecordAwareHSSFListener(this));
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final HSSFRequest request = new HSSFRequest();
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@ -373,33 +373,33 @@ public class Excel03SaxReader implements HSSFListener, ExcelSaxReader<Excel03Sax
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/**
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* 获取sheet索引，从0开始
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* <ul>
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* <li>Excel03中没有rid概念，如果传入'rId'开头，直接去除rId前缀，按照sheetIndex对待</li>
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* <li>Excel03中没有rid概念，如果传入'rId'开头，rid从1开始计数，直接去除rId前缀并减1，转换为sheetIndex</li>
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* <li>传入纯数字，表示sheetIndex</li>
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* <li>传入sheet名称，例如'sheet1'，则读取sheetName，sheetIndex使用-1表示。</li>
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* </ul>
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*
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* @param idOrRidOrSheetName Excel中的sheet id或者rid编号或sheet名称，从0开始，rid必须加rId前缀，例如rId0，如果为-1处理所有编号的sheet
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* @return sheet索引，从0开始
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* @param idOrRidOrSheetName Excel中的sheet id或者rid编号或sheet名称，从0开始，rid必须加rId前缀，例如rId1，从1开始，如果为-1处理所有编号的sheet
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* @since 5.5.5
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*/
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private int getSheetIndex(final String idOrRidOrSheetName) {
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private void initSheetIndexOrSheetName(final String idOrRidOrSheetName) {
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Assert.notBlank(idOrRidOrSheetName, "id or rid or sheetName must be not blank!");
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// rid直接处理
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if (StrUtil.startWithIgnoreCase(idOrRidOrSheetName, RID_PREFIX)) {
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return Integer.parseInt(StrUtil.removePrefixIgnoreCase(idOrRidOrSheetName, RID_PREFIX));
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// rid从1开始计数，此处转换为从0开始的索引
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this.sheetIndex = Integer.parseInt(StrUtil.removePrefixIgnoreCase(idOrRidOrSheetName, RID_PREFIX)) - 1;
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} else if(StrUtil.startWithIgnoreCase(idOrRidOrSheetName, SHEET_NAME_PREFIX)){
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// since 5.7.10，支持任意名称
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this.sheetName = StrUtil.removePrefixIgnoreCase(idOrRidOrSheetName, SHEET_NAME_PREFIX);
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} else {
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// 传入纯数字，表示sheetIndex
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try {
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return Integer.parseInt(idOrRidOrSheetName);
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this.sheetIndex = Integer.parseInt(idOrRidOrSheetName);
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} catch (final NumberFormatException ignore) {
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// 如果用于传入非数字，按照sheet名称对待
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this.sheetName = idOrRidOrSheetName;
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}
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}
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return -1;
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}
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// ---------------------------------------------------------------------------------------------- Private method end
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}
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@ -24,9 +24,9 @@ import java.io.InputStream;
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/**
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* Sax方式读取Excel接口，提供一些共用方法
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* @author Looly
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*
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* @param <T> 子对象类型，用于标记返回值this
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* @author Looly
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* @since 3.2.0
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*/
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public interface ExcelSaxReader<T> {
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@ -41,29 +41,41 @@ public interface ExcelSaxReader<T> {
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String SHEET_NAME_PREFIX = "sheetName:";
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/**
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* 开始读取Excel
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* 开始从文件中读取Excel
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*
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* @param file Excel文件
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* @param idOrRidOrSheetName Excel中的sheet id或者rid编号或sheet名称，rid必须加rId前缀，例如rId1，如果为-1处理所有编号的sheet
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* @param file Excel文件
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* @param idOrRidOrSheetName Excel中的sheet id或者rid编号或sheet名称，规则如下：
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* <ul>
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* <li>如果为-1，处理所有编号的sheet</li>
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* <li>如果为rId开头，例如rId1，表示读取指定编号的sheet，从1计数，即rId1表示第一个sheet</li>
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* <li>如果为sheet名称，例如sheet1，直接读取名车给对应sheet</li>
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* <li>如果为纯数字，在03中表示index，从0开始，07中表示sheet id，从1开始</li>
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* </ul>
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* @return this
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* @throws POIException POI异常
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*/
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T read(File file, String idOrRidOrSheetName) throws POIException;
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/**
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* 开始读取Excel，读取结束后并不关闭流
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* 开始从流中读取Excel，读取结束后并不关闭流
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*
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* @param in Excel流
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* @param idOrRidOrSheetName Excel中的sheet id或者rid编号，rid必须加rId前缀，例如rId1，如果为-1处理所有编号的sheet
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* @param in Excel流
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* @param idOrRidOrSheetName Excel中的sheet id或者rid编号或sheet名称，规则如下：
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* <ul>
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* <li>如果为-1，处理所有编号的sheet</li>
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* <li>如果为rId开头，例如rId1，表示读取指定编号的sheet，从1计数，即rId1表示第一个sheet</li>
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* <li>如果为sheet名称，例如sheet1，直接读取名车给对应sheet</li>
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* <li>如果为纯数字，在03中表示index，从0开始，07中表示sheet id，从1开始</li>
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* </ul>
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* @return this
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* @throws POIException POI异常
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*/
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T read(InputStream in, String idOrRidOrSheetName) throws POIException;
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/**
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* 开始读取Excel，读取所有sheet
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* 开始从路径中读取Excel，读取所有sheet
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*
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* @param path Excel文件路径
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* @param path Excel文件路径，如果是相对路径，则相对classpath
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* @return this
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* @throws POIException POI异常
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*/
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@ -72,7 +84,7 @@ public interface ExcelSaxReader<T> {
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}
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/**
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* 开始读取Excel，读取所有sheet
|
||||
* 开始从文件中读取Excel，读取所有sheet
|
||||
*
|
||||
* @param file Excel文件
|
||||
* @return this
|
||||
@ -83,7 +95,7 @@ public interface ExcelSaxReader<T> {
|
||||
}
|
||||
|
||||
/**
|
||||
* 开始读取Excel，读取所有sheet，读取结束后并不关闭流
|
||||
* 开始从流中读取Excel，读取所有sheet，读取结束后并不关闭流
|
||||
*
|
||||
* @param in Excel包流
|
||||
* @return this
|
||||
@ -94,22 +106,28 @@ public interface ExcelSaxReader<T> {
|
||||
}
|
||||
|
||||
/**
|
||||
* 开始读取Excel
|
||||
* 开始从路径中读取Excel
|
||||
*
|
||||
* @param path 文件路径
|
||||
* @param idOrRidOrSheetName Excel中的sheet id或者rid编号或sheet名称，rid必须加rId前缀，例如rId1，如果为-1处理所有编号的sheet
|
||||
* @param path 文件路径，如果是相对路径，则相对classpath
|
||||
* @param idOrRid Excel中的sheet id或者rid编号，rid必须加rId前缀，例如rId1，如果为-1处理所有编号的sheet
|
||||
* @return this
|
||||
* @throws POIException POI异常
|
||||
*/
|
||||
default T read(final String path, final int idOrRidOrSheetName) throws POIException {
|
||||
return read(FileUtil.file(path), idOrRidOrSheetName);
|
||||
default T read(final String path, final int idOrRid) throws POIException {
|
||||
return read(FileUtil.file(path), idOrRid);
|
||||
}
|
||||
|
||||
/**
|
||||
* 开始读取Excel
|
||||
*
|
||||
* @param path 文件路径
|
||||
* @param idOrRidOrSheetName Excel中的sheet id或者rid编号或sheet名称，rid必须加rId前缀，例如rId1，如果为-1处理所有编号的sheet
|
||||
* @param path 文件路径
|
||||
* @param idOrRidOrSheetName Excel中的sheet id或者rid编号或sheet名称，规则如下：
|
||||
* <ul>
|
||||
* <li>如果为-1，处理所有编号的sheet</li>
|
||||
* <li>如果为rId开头，例如rId1，表示读取指定编号的sheet，从1计数，即rId1表示第一个sheet</li>
|
||||
* <li>如果为sheet名称，例如sheet1，直接读取名车给对应sheet</li>
|
||||
* <li>如果为纯数字，在03中表示index，从0开始，07中表示sheet id，从1开始</li>
|
||||
* </ul>
|
||||
* @return this
|
||||
* @throws POIException POI异常
|
||||
*/
|
||||
@ -118,26 +136,34 @@ public interface ExcelSaxReader<T> {
|
||||
}
|
||||
|
||||
/**
|
||||
* 开始读取Excel
|
||||
* 开始从文件中读取Excel
|
||||
*
|
||||
* @param file Excel文件
|
||||
* @param rid Excel中的sheet rid编号，如果为-1处理所有编号的sheet
|
||||
* @param file Excel文件
|
||||
* @param idOrRid Excel中的sheet id或者rid编号，规则如下：
|
||||
* <ul>
|
||||
* <li>如果为-1，处理所有编号的sheet</li>
|
||||
* <li>如果为纯数字，在03中表示index，从0开始，07中表示sheet id，从1开始</li>
|
||||
* </ul>
|
||||
* @return this
|
||||
* @throws POIException POI异常
|
||||
*/
|
||||
default T read(final File file, final int rid) throws POIException{
|
||||
return read(file, String.valueOf(rid));
|
||||
default T read(final File file, final int idOrRid) throws POIException {
|
||||
return read(file, String.valueOf(idOrRid));
|
||||
}
|
||||
|
||||
/**
|
||||
* 开始读取Excel，读取结束后并不关闭流
|
||||
* 开始从流中读取Excel，读取结束后并不关闭流
|
||||
*
|
||||
* @param in Excel流
|
||||
* @param rid Excel中的sheet rid编号，如果为-1处理所有编号的sheet
|
||||
* @param in Excel流
|
||||
* @param idOrRid Excel中的sheet id或者rid编号，规则如下：
|
||||
* <ul>
|
||||
* <li>如果为-1，处理所有编号的sheet</li>
|
||||
* <li>如果为纯数字，在03中表示index，从0开始，07中表示sheet id，从1开始</li>
|
||||
* </ul>
|
||||
* @return this
|
||||
* @throws POIException POI异常
|
||||
*/
|
||||
default T read(final InputStream in, final int rid) throws POIException{
|
||||
return read(in, String.valueOf(rid));
|
||||
default T read(final InputStream in, final int idOrRid) throws POIException {
|
||||
return read(in, String.valueOf(idOrRid));
|
||||
}
|
||||
}
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user