ElasticSearch实战(三) 空查询、分页

接下来实现读取数据并在网页上以列表形式显示的功能。首先添加一些测试数据：

List indexQueries = Arrays.asList(
                new IndexQueryBuilder().withObject(new Blog(1, "Mary Jones", "Jane is an expert in her field", 80, parseDate("2019-06-21"))).build(),
                new IndexQueryBuilder().withObject(new Blog(2, "Jane Smith", "I am starting to get the hang of this...", 0, parseDate("2019-06-20"))).build(),
                new IndexQueryBuilder().withObject(new Blog(3, "John Smith", "The Query DSL is really powerful and flexible", 100, parseDate("2019-06-20"))).build(),
                new IndexQueryBuilder().withObject(new Blog(4, "Mary Jones", "Still trying this out...", 0, parseDate("2019-06-20"))).build(),
                new IndexQueryBuilder().withObject(new Blog(5, "Mary Jones", "However did I manage before Elasticsearch?", 200, parseDate("2019-06-19"))).build(),
                new IndexQueryBuilder().withObject(new Blog(6, "Jane Smith", "I like to collect rock albums", 0, parseDate("2019-06-19"))).build(),
                new IndexQueryBuilder().withObject(new Blog(7, "Douglas Fir", "I like to build cabinets", 50, parseDate("2019-06-19"))).build(),
                new IndexQueryBuilder().withObject(new Blog(8, "John Smith", "I love to go rock climbing", 40, parseDate("2019-06-18"))).build(),
                new IndexQueryBuilder().withObject(new Blog(9, "Mary Jones", "I am Mary Jones, welcome to my blog!", 500, parseDate("2019-06-17"))).build(),
                new IndexQueryBuilder().withObject(new Blog(10, "Mary Jones", "My first blog entry", 400, parseDate("2019-06-17"))).build()
        );
        elasticsearchTemplate.bulkIndex(indexQueries);

• 空查询

读取全部数据用matchAllQuery查询，controller代码：

    @Autowired
    private ElasticsearchTemplate elasticsearchTemplate;

    @RequestMapping("/blogs")
    public String query(Model model) {
        SearchQuery searchQuery = new NativeSearchQueryBuilder()
                .withQuery(QueryBuilders.matchAllQuery())
                .build();
        Page blogs = elasticsearchTemplate.queryForPage(searchQuery, Blog.class);
        model.addAttribute("blogs", blogs.getContent());
        return "index";
    }

页面代码同使用关系型数据库的方式完全相同，主要代码：

  

    
      Jonathan Burke Jr.
    
    
  
  

  

    
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效果如下：

• 排序

继续添加按日期倒序排序功能，只需增加一行代码：

        SearchQuery searchQuery = new NativeSearchQueryBuilder()
                .withQuery(QueryBuilders.matchAllQuery())
                .withSort(SortBuilders.fieldSort("date").order(SortOrder.DESC))
                .build();

• 分页

创建一个分页辅助类：

import org.springframework.data.domain.Page;

import java.util.List;

public class PageHelper {

    private long total;
    private List list;
    private int pageNum;
    private int pageSize;
    private int pages;
    private int previousPageNum;
    private int nextPageNum;
    private boolean previousPage;
    private boolean nextPage;
    private int[] navigatePageNums;

    public PageHelper(Page page, int pageNum, int pageSize) {

        this.list = page.getContent();
        this.total = page.getTotalElements();
        this.pageNum = pageNum;
        this.pageSize = pageSize;
        this.pages = page.getTotalPages();
        this.previousPage = false;
        this.nextPage = false;

        int startNum = 1;
        int endNum = pages;
        int navigateNums = 10; //导航栏显示数字个数
        if (pages <= navigateNums) {
        } else if ((pageNum + (navigateNums + 1) / 2) > pages) {
            startNum = pages - (navigateNums - 1);
            endNum = pages;
        } else if (pageNum <= (navigateNums + 1) / 2) {
            endNum = navigateNums;
        } else {
            if (navigateNums % 2 == 0) {
                startNum = pageNum - navigateNums / 2;
                endNum = pageNum + (navigateNums - 1) / 2;
            } else {
                startNum = pageNum - navigateNums / 2;
                endNum = pageNum + navigateNums / 2;
            }
        }
        this.navigatePageNums = new int[endNum - startNum + 1];
        for (int i = startNum; i <= endNum; i++) {
            this.navigatePageNums[i - startNum] = i;
        }

        for (int i = 0; i < this.pages; ++i) {
            this.navigatePageNums[i] = i + 1;
        }
        if (this.pageNum > 1) {
            this.previousPage = true;
            this.previousPageNum = this.pageNum - 1;
        }

        if (this.pageNum < this.pages) {
            this.nextPage = true;
            this.nextPageNum = this.pageNum + 1;
        }
    }

    //getter/setter略
}

controller改造后如下：

    @RequestMapping("/blogs")
    public String query(Model model, Integer pageNum, Integer pageSize) {

        if(pageNum == null || pageNum <= 0)
            pageNum = 1;
        if(pageSize == null || pageSize <= 0)
            pageSize = 5;

        SearchQuery searchQuery = new NativeSearchQueryBuilder()
                .withPageable(new QPageRequest(pageNum - 1, pageSize))
                .withQuery(QueryBuilders.matchAllQuery())
                .withSort(SortBuilders.fieldSort("date").order(SortOrder.DESC))
                .build();
        Page blogs = elasticsearchTemplate.queryForPage(searchQuery, Blog.class);
        model.addAttribute("blogs", blogs.getContent());
        model.addAttribute("pageHelper", new PageHelper<>(blogs, pageNum, pageSize));
        return "index";
    }

创建一个展示层的分页组件，pagenation.html：

    
    

        

            
            5
            10
            20
            50
            100
         
    
    

        

            

                
                    

                
                
                    
1
                
                
                    

                
            
        
    
    

在列表页引用该组件

重新运行后在页面底部显示分页栏：

 

 源码：

链接：https://pan.baidu.com/s/1CaQp5LrcWdLp0UXUPrPbKg 
提取码：t5qj