第三节,数据库查询
## 步骤
#### 1. 创建类 DataBaseController
创建 com.xnx3.wangmarket.learn.controller.DataBaseController 类,其内代码为:
````
package com.xnx3.wangmarket.learn.controller;
import java.util.List;
import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import com.xnx3.j2ee.entity.User;
import com.xnx3.j2ee.service.SqlService;
import com.xnx3.wangmarket.admin.controller.BaseController;
/**
* 网市场云建站系统 二次开发入门之第三节 数据库查询
* @author 管雷鸣
*/
@Controller
@RequestMapping("/")
public class DataBaseController extends BaseController {
/**
* 数据库相关操作
*/
@Resource
private SqlService sqlService;
/**
* 查询user用户表的信息
*/
@RequestMapping("/dbSelect${url.suffix}")
@ResponseBody
public String dbSelect(HttpServletRequest request){
List userList = sqlService.findBySqlQuery("SELECT * FROM user", User.class);
for (int i = 0; i < userList.size(); i++) {
User user = userList.get(i);
System.out.println(user.getId() + "-" + user.getUsername());
}
return "success";
}
}
````
##### 注意:
1. 数据库操作,使用 SqlService ,用此来操作数据库
2. User 对象(com.xnx3.j2ee.entity.User)为已针对数据表 user 创建好的实体类。
#### 2. 访问测试
访问 http://localhost:8080/dbSelect.do ,然后回到 Eclipse 控制台 Console,可以看到打印出的信息:
![](http://cdn.weiunity.com/site/473/news/faa4d9927fed449a9a10a1f60b3cb440.png)
## SqlService 更多文档 更多数据库相关方法说明,请参考:[http://www.xnx3.com/doc/wangmarket/com/xnx3/j2ee/service/SqlService.html](http://www.xnx3.com/doc/wangmarket/com/xnx3/j2ee/service/SqlService.html)
## SqlService 更多文档 更多数据库相关方法说明,请参考:[http://www.xnx3.com/doc/wangmarket/com/xnx3/j2ee/service/SqlService.html](http://www.xnx3.com/doc/wangmarket/com/xnx3/j2ee/service/SqlService.html)