修改 API，也使 PagingAndSortingQueryParams 支持 Gson。

src/main/java/xyz/zhouxy/plusone/commons/model/dto/PagingAndSortingQueryParams.java

@@ -0,0 +1,159 @@
+/*
+ * Copyright 2022-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xyz.zhouxy.plusone.commons.model.dto;
+
+import java.util.List;
+import java.util.Map;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+
+import javax.annotation.Nullable;
+
+import org.apache.commons.lang3.StringUtils;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableMap;
+
+import xyz.zhouxy.plusone.commons.annotation.Virtual;
+
+/**
+ * 分页排序查询参数
+ *
+ * <p>
+ * 根据传入的 {@code size} 和 {@code pageNum}，
+ * 提供 {@code getOffset} 方法计算 SQL 语句中 {@code offset} 的值。
+ * </p>
+ *
+ * @author <a href="http://zhouxy.xyz:3000/ZhouXY108">ZhouXY</a>
+ * @see PageResult
+ */
+public class PagingAndSortingQueryParams {
+
+    private static final int DEFAULT_PAGE_SIZE = 15;
+
+    private Integer size;
+    private Long pageNum;
+    private List<String> orderBy;
+
+    private static final Pattern sortStrPattern = Pattern.compile("^[a-zA-Z]\\w+-(desc|asc|DESC|ASC)$");
+
+    private final Map<String, String> sortableProperties;
+
+    public PagingAndSortingQueryParams(Map<String, String> sortableProperties) {
+        Preconditions.checkArgument(sortableProperties != null && !sortableProperties.isEmpty(),
+                "Sortable properties can not be empty.");
+        sortableProperties.forEach((k, v) ->
+                Preconditions.checkArgument(StringUtils.isNotBlank(k) && StringUtils.isNotBlank(v),
+                "Property name must not be blank."));
+        this.sortableProperties = ImmutableMap.copyOf(sortableProperties);
+    }
+
+    // Setters
+
+    public final void setOrderBy(@Nullable List<String> orderBy) {
+        this.orderBy = orderBy;
+    }
+
+    public final void setSize(@Nullable Integer size) {
+        this.size = size;
+    }
+
+    public final void setPageNum(@Nullable Long pageNum) {
+        this.pageNum = pageNum;
+    }
+
+    // Setters end
+
+    public final PagingParams buildPagingParams() {
+        final int sizeValue = this.size != null ? this.size : defaultSizeInternal();
+        final long pageNumValue = this.pageNum != null ? this.pageNum : 1L;
+        final List<SortableProperty> propertiesToSort = this.orderBy.stream().map(this::generateSortableProperty)
+                .collect(Collectors.toList());
+        return new PagingParams(sizeValue, pageNumValue, propertiesToSort);
+    }
+
+    @Virtual
+    protected int defaultSizeInternal() {
+        return DEFAULT_PAGE_SIZE;
+    }
+
+    @Override
+    public String toString() {
+        return "PagingAndSortingQueryParams ["
+                + "size=" + size
+                + ", pageNum=" + pageNum
+                + ", orderBy=" + orderBy
+                + ", sortableProperties=" + sortableProperties
+                + "]";
+    }
+
+    private SortableProperty generateSortableProperty(String orderByStr) {
+        Preconditions.checkArgument(PagingAndSortingQueryParams.sortStrPattern.matcher(orderByStr).matches());
+        String[] propertyNameAndOrderType = orderByStr.split("-");
+        Preconditions.checkArgument(propertyNameAndOrderType.length == 2);
+
+        String propertyName = propertyNameAndOrderType[0];
+        Preconditions.checkArgument(sortableProperties.containsKey(propertyName),
+                "The property name must be in the set of sortable properties.");
+        String columnName = sortableProperties.get(propertyName);
+        String orderType = propertyNameAndOrderType[1];
+        return new SortableProperty(propertyName, columnName, orderType);
+    }
+
+    public static final class SortableProperty {
+        private final String propertyName;
+        private final String columnName;
+        private final String orderType;
+
+        private final String sqlSnippet;
+
+        SortableProperty(String propertyName, String columnName, String orderType) {
+            this.propertyName = propertyName;
+            this.columnName = columnName;
+            Preconditions.checkArgument("ASC".equalsIgnoreCase(orderType) || "DESC".equalsIgnoreCase(orderType));
+            this.orderType = orderType.toUpperCase();
+
+            this.sqlSnippet = this.propertyName + " " + this.orderType;
+        }
+
+        public String getPropertyName() {
+            return propertyName;
+        }
+
+        public String getColumnName() {
+            return columnName;
+        }
+
+        public String getOrderType() {
+            return orderType;
+        }
+
+        public String getSqlSnippet() {
+            return sqlSnippet;
+        }
+
+        @Override
+        public String toString() {
+            return "SortableProperty ["
+                    + "propertyName=" + propertyName
+                    + ", columnName=" + columnName
+                    + ", orderType=" + orderType
+                    + "]";
+        }
+    }
+
+}

src/main/java/xyz/zhouxy/plusone/commons/model/dto/PagingParams.java

@@ -0,0 +1,47 @@
+package xyz.zhouxy.plusone.commons.model.dto;
+
+import java.util.Collections;
+import java.util.List;
+
+import xyz.zhouxy.plusone.commons.model.dto.PagingAndSortingQueryParams.SortableProperty;
+
+public class PagingParams {
+
+    private final int size;
+    private final long pageNum;
+    private final long offset;
+    private final List<SortableProperty> orderBy;
+
+    PagingParams(int size, long pageNum, List<SortableProperty> orderBy) {
+        this.size = size;
+        this.pageNum = pageNum;
+        this.offset = (pageNum - 1) * size;
+        this.orderBy = orderBy;
+    }
+
+    // Getters
+
+    public final List<SortableProperty> getOrderBy() {
+        return Collections.unmodifiableList(this.orderBy);
+    }
+
+    public final int getSize() {
+        return this.size;
+    }
+
+    public final long getPageNum() {
+        return this.pageNum;
+    }
+
+    public final long getOffset() {
+        return this.offset;
+    }
+
+    // Getters end
+
+    @Override
+    public String toString() {
+        return "PageInfo [size=" + size + ", pageNum=" + pageNum + ", orderBy=" + orderBy + ", offset="
+                + getOffset() + "]";
+    }
+}