# ssm整合：新增搜尋功能
###### tags: `ssm整合`

### Dao層的BookMapper.java
先確定我們要新增的方法到Dao層中

Books queryBookByName(@Param("bookName") String bookName);

### BookMapper.xml
底層的SQL搜尋語法，用來實現Dao層的方法

 <select id="queryBookByName" resultType="Books">
        select * from ssmbuild.books where bookName = #{bookName}
    </select>

### Service層的BookService.java

Books queryBookByName(String bookName);

### Service層的實現類：BookServiceImpl.java
調用dao層的操作

  @Override
    public Books queryBookByName(String bookName) {
        return bookMapper.queryBookByName(bookName);
    }

### BookController

//查詢書籍
    @RequestMapping("/queryBook")
    public String queryBook(String queryBookName,Model model){
        Books books = bookService.queryBookByName(queryBookName);
        System.out.println("books=>" + books);
        //將查詢到的書籍裝入列表中         
        List<Books> list = new ArrayList<Books>();
        list.add(books);
        //若查無書籍，則顯示錯誤
        if(books == null){
            list = bookService.queryAllBook();
            model.addAttribute("error","未查詢到");
        }
        //返回到allBook頁面，使用allBook頁面設計好的表單來呈現結果
        model.addAttribute("list",list);
        return "allBook";
    }

若查詢得到該書籍，會在allBook呈現

若查無書籍，會回報錯誤，並回到原始首頁