feat: cache article list, #119

src/main/java/com/gm/wj/redis/RedisService.java

 package com.gm.wj.redis;
 
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.domain.PageImpl;
 import org.springframework.data.redis.core.*;
 import org.springframework.stereotype.Service;
 
@@ -30,6 +31,10 @@ public class RedisService {
         return redisTemplate.opsForValue().get(key);
     }
 
+//    public <T> PageImpl<T> getPage(String key) {
+//        return redisTemplate.opsForValue().get(key);
+//    }
+
     public Boolean delete(String key) {
         return redisTemplate.delete(key);
     }

src/main/java/com/gm/wj/service/BookService.java

 package com.gm.wj.service;
 
+import com.gm.wj.config.RedisConfig;
 import com.gm.wj.dao.BookDAO;
 import com.gm.wj.entity.Book;
 import com.gm.wj.entity.Category;
 import com.gm.wj.redis.RedisService;
 import com.gm.wj.util.CastUtils;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.cache.annotation.Cacheable;
 import org.springframework.data.domain.Sort;
 import org.springframework.stereotype.Service;
 
-import javax.annotation.processing.Processor;
 import java.util.List;
-import java.util.Timer;
 
 /**
  * @author Evan
@@ -26,18 +26,29 @@ public class BookService {
     @Autowired
     private RedisService redisService;
 
-//    @Cacheable(value = RedisConfig.REDIS_KEY_DATABASE)
     public List<Book> list() {
+        List<Book> books;
         String key = "booklist";
-        List<Book> books = CastUtils.castList(redisService.get(key), Book.class);
-        if (books == null) {
+        Object bookCache = redisService.get(key);
+
+        if (bookCache == null) {
             Sort sort = new Sort(Sort.Direction.DESC, "id");
             books = bookDAO.findAll(sort);
             redisService.set(key, books);
+        } else {
+            books = CastUtils.objectConvertToList(bookCache, Book.class);
         }
         return books;
     }
 
+//    @Cacheable(value = RedisConfig.REDIS_KEY_DATABASE)
+//    public List<Book> list() {
+//        List<Book> books;
+//        Sort sort = new Sort(Sort.Direction.DESC, "id");
+//        books = bookDAO.findAll(sort);
+//        return books;
+//    }
+
     public void addOrUpdate(Book book) {
         redisService.delete("booklist");
         bookDAO.save(book);

src/main/java/com/gm/wj/service/JotterArticleService.java

@@ -2,6 +2,8 @@ package com.gm.wj.service;
 
 import com.gm.wj.dao.JotterArticleDAO;
 import com.gm.wj.entity.JotterArticle;
+import com.gm.wj.redis.RedisService;
+import com.gm.wj.util.MyPage;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageRequest;
@@ -16,12 +18,33 @@ import org.springframework.stereotype.Service;
 public class JotterArticleService {
     @Autowired
     JotterArticleDAO jotterArticleDAO;
+    @Autowired
+    RedisService redisService;
+
+    public MyPage list(int page, int size) {
+        MyPage<JotterArticle> articles;
+        String key = "articlepage:" + page;
+        Object articlePageCache = redisService.get(key);
 
-    public Page list(int page, int size) {
-        Sort sort = new Sort(Sort.Direction.DESC, "id");
-        return jotterArticleDAO.findAll(PageRequest.of(page, size, sort));
+        if (articlePageCache == null) {
+            Sort sort = new Sort(Sort.Direction.DESC, "id");
+            Page<JotterArticle> articlesInDb = jotterArticleDAO.findAll(PageRequest.of(page, size, sort));
+            articles = new MyPage<>(articlesInDb);
+            redisService.set(key, articles);
+        } else {
+            articles = (MyPage<JotterArticle>) articlePageCache;
+        }
+        return articles;
     }
 
+//    用于复现异常
+//    @Cacheable(value = RedisConfig.REDIS_KEY_DATABASE)
+//    public Page list(int page, int size) {
+//        Sort sort = new Sort(Sort.Direction.DESC, "id");
+//        return jotterArticleDAO.findAll(PageRequest.of(page, size, sort));
+//    }
+
+
     public JotterArticle findById(int id) {
         return jotterArticleDAO.findById(id);
     }

src/main/java/com/gm/wj/util/CastUtils.java

@@ -8,8 +8,7 @@ import java.util.List;
  * @date 2020/5/31 19:04
  */
 public class CastUtils {
-    public static <T> List<T> castList(Object obj, Class<T> clazz)
-    {
+    public static <T> List<T> objectConvertToList(Object obj, Class<T> clazz) {
         List<T> result = new ArrayList<T>();
         if(obj instanceof List<?>)
         {

src/main/java/com/gm/wj/util/MyPage.java

+package com.gm.wj.util;
+
+import org.springframework.data.domain.Page;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+
+/**
+ * @Author Evan
+ * @Date 2020/6/10
+ */
+public class MyPage<T> implements Iterable<T>, Serializable {
+    private static final long serialVersionUID = -3720998571176536865L;
+    private List<T> content = new ArrayList<>();
+    private long totalElements;
+    private int pageNumber;
+    private int pageSize;
+    private boolean first;
+    private boolean last;
+    private boolean empty;
+    private int totalPages;
+    private int numberOfElements;
+
+    public MyPage() {
+    }
+
+    //只用把原来的page类放进来即可
+    public MyPage(Page<T> page) {
+        this.content = page.getContent();
+        this.totalElements = page.getTotalElements();
+        this.pageNumber = page.getPageable().getPageNumber();
+        this.pageSize = page.getPageable().getPageSize();
+        this.numberOfElements = page.getNumberOfElements();
+    }
+
+    //是否有前一页
+    public boolean hasPrevious() {
+        return getPageNumber() > 0;
+    }
+
+    //是否有下一页
+    public boolean hasNext() {
+        return getPageNumber() + 1 < getTotalPages();
+    }
+
+    //是否第一页
+    public boolean isFirst() {
+        return !hasPrevious();
+    }
+
+    //是否最后一页
+    public boolean isLast() {
+        return !hasNext();
+    }
+
+    //获取内容
+    public List<T> getContent() {
+        return Collections.unmodifiableList(content);
+    }
+
+    //设置内容
+    public void setContent(List<T> content) {
+        this.content = content;
+    }
+
+    //是否有内容
+    public boolean hasContent() {
+        return getNumberOfElements() > 0;
+    }
+
+    //获取单页大小
+    public int getPageSize() {
+        return pageSize;
+    }
+
+    //设置单页大小
+    public void setPageSize(int pageSize) {
+        this.pageSize = pageSize;
+    }
+
+    //获取全部元素数目
+    public long getTotalElements() {
+        return totalElements;
+    }
+
+    //设置全部元素数目
+    public void setTotalElements(long totalElements) {
+        this.totalElements = totalElements;
+    }
+
+    //设置是否第一页
+    public void setFirst(boolean first) {
+        this.first = first;
+    }
+
+    // 设置是否最后一页
+    public void setLast(boolean last) {
+        this.last = last;
+    }
+
+    //获取当前页号
+    public int getPageNumber() {
+        return pageNumber;
+    }
+
+    //设置当前页号
+    public void setPageNumber(int pageNumber) {
+        this.pageNumber = pageNumber;
+    }
+
+    //获取总页数
+    public int getTotalPages() {
+        return getPageSize() == 0 ? 1 : (int) Math.ceil((double) totalElements / (double) getPageSize());
+    }
+
+    //设置总页数
+    public void setTotalPages(int totalPages) {
+        this.totalPages = totalPages;
+    }
+
+    //获取单页元素数目
+    public int getNumberOfElements() {
+        return numberOfElements;
+    }
+
+    //设置单页元素数目
+    public void setNumberOfElements(int numberOfElements) {
+        this.numberOfElements = numberOfElements;
+    }
+
+    //判断是否为空
+    public boolean isEmpty() {
+        return !hasContent();
+    }
+
+    //设置是否为空
+    public void setEmpty(boolean empty) {
+        this.empty = empty;
+    }
+
+    //迭代器
+    @Override
+    public Iterator<T> iterator() {
+        return getContent().iterator();
+    }
+}