错误400-The request sent by the client was syntactically incorrect

Posted 2020-10-26 Shaw_喆宇

出错部分是学习SpringMVC 时学习https://my.oschina.net/gaussik/blog/640164，在添加博客文章部分出现了这个问题。

 

The request sent by the client was syntactically incorrect 说的意思是：由客户端发送的请求是语法上是不正确的。

上网找了很多资料，大部分都是说前端jsp页面的控件名称（name）和controller中接收的参数名称不一致，检查以后确实存在这个问题，修改以后还是没有解决，这说明别的地方还存在问题。

网上还有一种说法，就是提交表单数据类型与model不匹配，或方法参数顺序错误，这主要是json时会出现这个问题，但我并没有用到json，是直接用类的，所以照着修改了以后还是没有解决。（详见http://cuisuqiang.iteye.com/blog/2054234）

再有一种就是form表单中有日期,Spring不知道该如何转换,如要在实体类的日期属性上加@DateTimeFormat(pattern="yyyy-MM-dd")注解，添加以后确实解决了。

public class BlogEntity {
    private int id;
    private String title;
    private UserEntity userByUserId;
    private String context;
    @DateTimeFormat(pattern="yyyy-MM-dd")
    private Date pubDate;

 

P.S.在修改这个bug的过程中，真的是学到了。这个部分的前端可以获取值，但到controller时就没有接收到了。

    @RequestMapping(value = "/admin/blogs/addP", method = RequestMethod.POST)
    public String addBlogPost(@ModelAttribute("blog") BlogEntity blogEntity){
        //打印博客标题
        System.out.println(blogEntity.getTitle());
        //打印博客作者
        System.out.println(blogEntity.getUserByUserId().getNickname());
        blogRepository.saveAndFlush(blogEntity);
        return "redirect:/admin/blogs";
    }

这是controller的部分

 

<form:form action="/admin/blogs/addP" method="post" commandName="blog" role="form">
        <div class="form-group">
            <%--@declare id="title"--%><label for="title">Title:</label>
            <input type="text" name="title" id="title" class="form-control" placeholder="Enter Title:">
        </div>
        <div class="form-group">
                <%--@declare id="userbyuserid.id"--%><label for="userByUserId.id">Author:</label>
                <select class="form-control" id="userByUserId.id" name="userByUserId.id">
                    <c:forEach items="${userList}" var="user">
                        <option value="${user.id}">${user.nickname},${user.firstName} ${user.lastName}</option>
                    </c:forEach>
                </select>
        </div>
        <div class="form-group">
            <%--@declare id="context"--%><label for="context">Content:</label>
            <textarea class="form-control" id="context" name="context" rows="3" placeholder="Please Input Content"></textarea>
        </div>
        <div class="form-group">
            <%--@declare id="pubdate"--%><label for="pubDate">Publish Date:</label>
            <input type="date" class="form-control" id="pubDate" name="pubDate">
        </div>
        <div class="form-group">
            <button type="submit" class="btn btn-sm btn-success">提交</button>
        </div>
    </form:form>

这是jsp的部分。

 

package com.euphe.model;

import org.springframework.format.annotation.DateTimeFormat;

import javax.persistence.*;
import java.util.Date;

@Entity
@Table(name = "blog", schema = "blog")
public class BlogEntity {
    private int id;
    private String title;
    private UserEntity userByUserId;
    private String context;
    @DateTimeFormat(pattern="yyyy-MM-dd")
    private Date pubDate;


    @Id
    @Column(name = "id", nullable = false)
    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    @Basic
    @Column(name = "title", nullable = false, length = 100)
    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }


    @ManyToOne
    @JoinColumn(name = "user_id", referencedColumnName = "id", nullable = false)
    public UserEntity getUserByUserId() {
        return userByUserId;
    }

    public void setUserByUserId(UserEntity userByUserId) {
        this.userByUserId = userByUserId;
    }

    @Basic
    @Column(name = "context", nullable = true, length = 255)
    public String getContext() {
        return context;
    }

    public void setContext(String context) {
        this.context = context;
    }

    @Basic
    @Column(name = "pub_date", nullable = false)
    public Date getPubDate() {
        return pubDate;
    }

    public void setPubDate(Date pubDate) {
        this.pubDate = pubDate;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        BlogEntity that = (BlogEntity) o;

        if (id != that.id) return false;
        if (title != null ? !title.equals(that.title) : that.title != null) return false;
        if (context != null ? !context.equals(that.context) : that.context != null) return false;
        if (pubDate != null ? !pubDate.equals(that.pubDate) : that.pubDate != null) return false;

        return true;
    }

    @Override
    public int hashCode() {
        int result = id;
        result = 31 * result + (title != null ? title.hashCode() : 0);
        result = 31 * result + (context != null ? context.hashCode() : 0);
        result = 31 * result + (pubDate != null ? pubDate.hashCode() : 0);
        return result;
    }

}

这是entity部分，即类的定义

 

打断点都打在entity上，发现没能接收的值只有pubDate，所以一步一步地往下进行调试，这时因为是嵌套的框架，所以会进入到框架内的代码。不要慌张，慢慢往下走会发现throws exception了，这时可以发现是类型转换出了问题，前端传入的是string，但后端接收的是date类型，其中没办法转换。

 

其实还有一种方法，可以类似这样（http://www.mkyong.com/spring-mvc/spring-mvc-form-handling-example/）

// save or update user
    // 1. @ModelAttribute bind form value
    // 2. @Validated form validator
    // 3. RedirectAttributes for flash value
    @RequestMapping(value = "/users", method = RequestMethod.POST)
    public String saveOrUpdateUser(@ModelAttribute("userForm") @Validated User user,
            BindingResult result, Model model,
            final RedirectAttributes redirectAttributes) {

        logger.debug("saveOrUpdateUser() : {}", user);

        if (result.hasErrors()) {
            populateDefaultModel(model);
            return "users/userform";
        } else {

            // Add message to flash scope
            redirectAttributes.addFlashAttribute("css", "success");
            if(user.isNew()){
              redirectAttributes.addFlashAttribute("msg", "User added successfully!");
            }else{
              redirectAttributes.addFlashAttribute("msg", "User updated successfully!");
            }

            userService.saveOrUpdate(user);

            // POST/REDIRECT/GET
            return "redirect:/users/" + user.getId();

            // POST/FORWARD/GET
            // return "user/list";

        }

    }

    // show add user form
    @RequestMapping(value = "/users/add", method = RequestMethod.GET)
    public String showAddUserForm(Model model) {

        logger.debug("showAddUserForm()");

        User user = new User();

        // set default value
        user.setName("mkyong123");
        user.setEmail("[email protected]");
        user.setAddress("abc 88");
        user.setNewsletter(true);
        user.setSex("M");
        user.setFramework(new ArrayList<String>(Arrays.asList("Spring MVC", "GWT")));
        user.setSkill(new ArrayList<String>(Arrays.asList("Spring", "Grails", "Groovy")));
        user.setCountry("SG");
        user.setNumber(2);
        model.addAttribute("userForm", user);

        populateDefaultModel(model);

        return "users/userform";

    }

将一个entity打开，一个一个set，这样可以转换模式。