第9講 9.3 動態查詢specification
阿新 • • 發佈：2018-11-16
1，BookDao 新增繼承，JapSpecificationExecutor<Book>,
ps:本例中兩個介面可以忽略
| package com.cruise.dao; import java.util.List; import org.springframework.data.jpa.repository.JpaRepository; import org.springframework.data.jpa.repository.JpaSpecificationExecutor; import org.springframework.data.jpa.repository.Query; import com.cruise.entity.Book; public interface BookDao extends JpaRepository<Book, Integer>,JpaSpecificationExecutor<Book>{ @Query("select b from Book b where b.name like %?1%") public List<Book> queryByName(String bookName); @Query(value="select * from t_book order by RAND() limit ?1",nativeQuery=true) public List<Book> randomList(Integer num); } |
2, Controller寫方發，寫一個內部類
注意 當new Specification<Book>() {}導包：import org.springframework.data.jpa.domain.Specification;
| @RequestMapping("/list2") public ModelAndView list2(Book book){ ModelAndView mav = new ModelAndView(); List<Book> bookList = bookDao.findAll(new Specification<Book>() { @Override public Predicate toPredicate(Root<Book> root, CriteriaQuery<?> query, CriteriaBuilder cb) { Predicate predicate = cb.conjunction(); if(book!=null){ if(book.getName()!=null && !"".equals(book.getName())){ predicate.getExpressions().add(cb.like(root.get("name"), "%"+book.getName()+"%")); } } if(book!=null){ if(book.getAuthor()!=null && !"".equals(book.getAuthor())){ predicate.getExpressions().add(cb.like(root.get("author"), "%"+book.getAuthor()+"%")); } } return predicate; } }); mav.addObject("bookList", bookList); mav.setViewName("bookList"); return mav; } mav.addObject("bookList", bookList); mav.setViewName("bookList"); return mav; } |
3，在bookAdd.ftl 中新增查詢前臺新增：form表單，
<form action="/book/list2" method="post">
圖書名稱：<input type="text" name="name"/> 圖書作者：<input type="text" name="author"/><br/>
<input type="submit" value="查詢"/>
</form>
| <!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>圖書列表</title> </head> <body> <a href="/bookAdd.html">新增</a> <form action="/book/list2" method="post"> 圖書名稱：<input type="text" name="name"/> 圖書作者：<input type="text" name="author"/><br/> <input type="submit" value="查詢"/> </form> <table> <tr> <th>編號</th> <th>名稱</th> <th>作者</th> <th>操作</th> </tr> <#list bookList as book> <tr> <td>${book.id}</td> <td>${book.name}</td> <td>${book.author}</td> <td> <a href="/book/preupdate/${book.id}">修改</a> <a href="/book/delete?id=${book.id}">刪除</a> </td> </tr> </#list> </table> </body> </html> |
4，測試
