SpringMVC实现RESTful服务

我们利用搭建SSM环境整合通用Mapper和PageHelper这篇博文搭建的SSM环境来讲解SpringMVC实现RESTful服务。

查询资源

测试：

新增资源

第一次测试：

这个时候显示新增成功了。我们再来看看数据库中是否存在这条数据了。

我们这次在重新提交一次：

更新资源

默认情况下，PUT请求是无法提交表单数据的，需要在web.xml中添加过滤器解决：

    <!-- 解决PUT请求无法提交表单数据的问题 -->
    <filter>
        <filter-name>HttpMethodFilter</filter-name>
        <filter-class>org.springframework.web.filter.HttpPutFormContentFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>HttpMethodFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

测试：

删除资源

需要在web.xml中添加过滤器解决DELETE请求无法提交表单数据的问题：

<!-- 
        将POST请求转化为DELETE或者是PUT
        要用_method指定真正的请求参数
     -->
    <filter>
        <filter-name>HiddenHttpMethodFilter</filter-name>
        <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>HiddenHttpMethodFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

测试：

Controller 代码

package my.ssm.controller;

import my.ssm.pojo.User;
import my.ssm.service.UserService;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;


@RequestMapping("new/user")
@Controller
public class NewUserController {

    @Autowired
    private UserService userService;

    // 根据用户id查询用户信息
    @RequestMapping(value = "{id}", method = RequestMethod.GET)
    @ResponseBody
    public ResponseEntity<User> queryUserById(@PathVariable("id") Long id) {
        try {
            User user = this.userService.queryUserById(id);
            if (null == user) {
                // 资源不存在，响应404
                return ResponseEntity.status(HttpStatus.NOT_FOUND).body(null);
            }
            // 资源存在，响应200
            // return ResponseEntity.status(HttpStatus.OK).body(user);
            return ResponseEntity.ok(user);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body(null);
    }

    /**
     * 新增用户
     * 
     * @param user
     * @return
     */
    @RequestMapping(method = RequestMethod.POST)
    public ResponseEntity<Void> saveUser(User user) {
        try {
            Boolean bool = this.userService.saveUser(user);
            if (bool) {
                // 新增成功，响应201
                return ResponseEntity.status(HttpStatus.CREATED).build();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        // 新增失败，响应500
        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
    }

    /**
     * 更新用户
     * @param user
     * @return
     */
    @RequestMapping(method = RequestMethod.PUT)
    public ResponseEntity<Void> updateUser(User user) {
        try {
            Boolean bool = this.userService.updateUser(user);
            if (bool) {
                // 更新成功，响应204
                return ResponseEntity.status(HttpStatus.NO_CONTENT).build();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        // 新增失败，响应500
        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
    }

    /**
     * 删除用户
     * 
     * @param id
     * @return
     */
    @RequestMapping(method = RequestMethod.DELETE)
    public ResponseEntity<Void> deleteUser(@RequestParam(value = "id", defaultValue = "0") Long id) {
        try {
            if (id.longValue() == 0) {
                // 没有传递参数，响应状态码400
                return ResponseEntity.status(HttpStatus.BAD_REQUEST).build();
            }
            Boolean bool = this.userService.deleteUser(id);
            if (bool) {
                // 删除成功，响应204
                return ResponseEntity.status(HttpStatus.NO_CONTENT).build();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        // 删除失败，响应500
        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
    }

}

Service 代码

package my.ssm.service;

import java.util.List;

import my.ssm.bean.EasyUIResult;
import my.ssm.mapper.UserMapper;
import my.ssm.pojo.User;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.github.abel533.entity.Example;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;

@Service
public class UserService {

    @Autowired
    private UserMapper userMapper;

    public EasyUIResult queryUserList(Integer page, Integer rows) {

        // 设置分页参数
        PageHelper.startPage(page, rows);

        // 查询User数据
        Example example = new Example(User.class);
        example.setOrderByClause("updated DESC"); // 设置排序条件
        List<User> users = this.userMapper.selectByExample(example);

        // 获取分页后的信息
        PageInfo<User> pageInfo = new PageInfo<User>(users);

        return new EasyUIResult(pageInfo.getTotal(), pageInfo.getList());
    }

    public User queryUserById(Long id) {
        return this.userMapper.selectByPrimaryKey(id);
    }

    public Boolean saveUser(User user) {
        return this.userMapper.insert(user) == 1;
    }

    public Boolean updateUser(User user) {
        return this.userMapper.updateByPrimaryKeySelective(user) == 1;
    }

    public Boolean deleteUser(Long id) {
        return this.userMapper.deleteByPrimaryKey(id) == 1;
    }


}