Page to PageInfo 时可以指定转换函数来转换 List 值的类型。

Author: abel533

src/main/java/com/github/pagehelper/Page.java

@@ -352,13 +352,49 @@ public Page<E> countColumn(String columnName) {
     }
 
     public PageInfo<E> toPageInfo() {
-        PageInfo<E> pageInfo = new PageInfo<E>(this);
+        return new PageInfo<E>(this);
+    }
+
+    public <T> PageInfo<T> toPageInfo(Function<E, T> function) {
+        List<T> list = new ArrayList<T>(this.size());
+        for (E e : this) {
+            list.add(function.apply(e));
+        }
+        PageInfo<T> pageInfo = new PageInfo<T>(list);
+        pageInfo.setPageNum(this.getPageNum());
+        pageInfo.setPageSize(this.getPageSize());
+        pageInfo.setPages(this.getPages());
+        pageInfo.setStartRow(this.getStartRow());
+        pageInfo.setEndRow(this.getEndRow());
+        pageInfo.calcByNavigatePages(PageInfo.DEFAULT_NAVIGATE_PAGES);
         return pageInfo;
     }
 
     public PageSerializable<E> toPageSerializable() {
-        PageSerializable<E> serializable = new PageSerializable<E>(this);
-        return serializable;
+        return new PageSerializable<E>(this);
+    }
+
+    public <T> PageSerializable<T> toPageSerializable(Function<E, T> function) {
+        List<T> list = new ArrayList<T>(this.size());
+        for (E e : this) {
+            list.add(function.apply(e));
+        }
+        return new PageSerializable<T>(list);
+    }
+
+    /**
+     * 兼容低版本 Java 7-
+     */
+    public interface Function<E, T> {
+
+        /**
+         * Applies this function to the given argument.
+         *
+         * @param t the function argument
+         * @return the function result
+         */
+        T apply(E t);
+
     }
 
     public <E> Page<E> doSelectPage(ISelect select) {

src/main/java/com/github/pagehelper/PageInfo.java

@@ -39,6 +39,7 @@
  */
 @SuppressWarnings({"rawtypes", "unchecked"})
 public class PageInfo<T> extends PageSerializable<T> {
+    public static final int DEFAULT_NAVIGATE_PAGES = 8;
     //当前页
     private int pageNum;
     //每页的数量
@@ -87,7 +88,7 @@ public PageInfo() {
      * @param list
      */
     public PageInfo(List<T> list) {
-        this(list, 8);
+        this(list, DEFAULT_NAVIGATE_PAGES);
     }
 
     /**
@@ -124,13 +125,7 @@ public PageInfo(List<T> list, int navigatePages) {
             this.endRow = list.size() > 0 ? list.size() - 1 : 0;
         }
         if (list instanceof Collection) {
-            this.navigatePages = navigatePages;
-            //计算导航页
-            calcNavigatepageNums();
-            //计算前后页，第一页，最后一页
-            calcPage();
-            //判断页面边界
-            judgePageBoudary();
+            calcByNavigatePages(navigatePages);
         }
     }
 
@@ -142,6 +137,16 @@ public static <T> PageInfo<T> of(List<T> list, int navigatePages) {
         return new PageInfo<T>(list, navigatePages);
     }
 
+    public void calcByNavigatePages(int navigatePages) {
+        setNavigatePages(navigatePages);
+        //计算导航页
+        calcNavigatepageNums();
+        //计算前后页，第一页，最后一页
+        calcPage();
+        //判断页面边界
+        judgePageBoudary();
+    }
+
     /**
      * 计算导航页
      */