Rest使用中的一些坑

1. Rest最佳场景

Rest最佳实践，Json作为通信载体

2. Rest应用场景

如下3个场景中，主要讨论，在请求 Put Delete 时：如何正确请求 如何正确传参

情景1：发送Post请求，中途转为Put Delete

浏览器本身只支持 get 和 post 请求，作为客户端，使用Rest时，如果需要发送 put 和 delete 请求，则：

<form action="${pageContext.request.contextPath}/rest04/users" method="post">
    <input type="hidden" name="_method" value="put">
    <input type="hidden" name="id" value="1">
    <input type="text" name="name" value="zhj">
    <input type="text" name="gender" value="true">
    <input type="text" name="birth" value="2019-12-12">
    <input type="submit" value="修改">
form>

<filter>
    <filter-name>httpMethodFilterfilter-name>
    <filter-class>org.springframework.web.filter.HiddenHttpMethodFilterfilter-class>
filter>
<filter-mapping>
    <filter-name>httpMethodFilterfilter-name>
    <url-pattern>/*url-pattern>
filter-mapping>

// 3. 定义domain
public class User {
    private Integer id;
    private String name;
    private Boolean gender;
    @DateTimeFormat(pattern = "yyyy-MM-dd")
    private Date birth;
}
// 4. 定义Handler，正常接收参数！！！！！
@RequestMapping(value="/users",method = RequestMethod.PUT)
@ResponseBody
//正常接收即可，因为此时发送的依然是post请求，tomcat已经获取到参数
public MyRequestStatus updateUser(User user) {
    System.out.println("update One user2:"+user);
    MyRequestStatus status = new MyRequestStatus("update", "ok");
    return status;
}

情景2：直接发送Put Delete请求

tomcat不处理put请求的请求体，其中参数不接收

var xhr = new XMLHttpRequest(); 
xhr.open("put","${pageContext.request.contextPath}/rest04/users");//ajax发送正常的put请求
xhr.setRequestHeader("content-type","application/x-www-form-urlencoded");
xhr.send("id=1&name=zhj&gender=true&birth=2019-12-12");//携带参数

// 2. 定义domain
public class User {
    private Integer id;
    private String name;
    private Boolean gender;
    @DateTimeFormat(pattern = "yyyy-MM-dd")
    private Date birth;
}
// 3.定义Handler，此时无法接收到请求参数！！！！！
@RequestMapping(value="/users",method = RequestMethod.PUT)
@ResponseBody
public MyRequestStatus updateUser(User user) {//此时无法接收到请求参数！！！！
    System.out.println("update One user2:"+user);
    MyRequestStatus status = new MyRequestStatus("update", "ok");
    return status;
}

<filter>
    <filter-name>putfilter-name>
    <filter-class>org.springframework.web.filter.HttpPutFormContentFilterfilter-class>
filter>
<filter-mapping>
    <filter-name>putfilter-name>
    <url-pattern>/*url-pattern>
filter-mapping>

情景3：直接发送Put请求,但携带Json格式数据参数

var xhr = new XMLHttpRequest(); 
xhr.open("put","${pageContext.request.contextPath}/rest04/users");//ajax发送正常的put请求
xhr.setRequestHeader("content-type","application/json");
xhr.send('{"id":1,"name":"zhj","gender":true,"birth":"2019/12/12"}');//携带Json数据参数

public class User {
    private Integer id;
    private String name;
    private Boolean gender;
    @JsonFormat(pattern = "yyyy/MM/dd")
    private Date birth;
}
@RequestMapping(value="/users",method = RequestMethod.PUT)
@ResponseBody
public MyRequestStatus updateUser(@RequestBody User user) {//通过@RequestBody收参！！！！
    System.out.println("update One user2:"+user);
    MyRequestStatus status = new MyRequestStatus("update", "ok");
    return status;
}

3. RestComponent

RestFul Controller

资源：用户  /users   GET  POST  PUT
     某一个用户   /users/{id}  GET  DELETE
     分页用户  /users/{pageNum}/{pageSize}  GET

@Controller
public class RestController {
    @GetMapping("/users")
    @ResponseBody
    public List<User> queryAllUsers(){//查询所有用户
        System.out.println("get");
        List<User> users = ....
        return users;
    }

    @PostMapping("/users")
    public String addUser(User user){//增加用户
        System.out.println("Post user :"+user);
        return "index";
    }
	
	//更新用户
    @PutMapping("/users")
    public String updateUser(@RequestBody User user){
        System.out.println("Put user" user:"+user);
        return "index";
    }
    
    // 查询id为x的用户
    @GetMapping("/users/{id}")
    public String queryOneUser(@PathVariable Integer id){//@PathVariable 接收路径中的值
        System.out.println("Get user id:"+id);
        return "index";
    }
    
    //删除用户
    @DeleteMapping("/users/{id}")
    public String deleteOneUser(@PathVariable Integer id){//@PathVariable 接收路径中的值
        System.out.println("delete user id:"+id);
        return "index";
    }

    // 查询分页用户
    @GetMapping("/users/{pageNum}/{pageSize}")
    @ResponseBody
    public List<User> queryAllUsers(@PathVariable Integer pageNum,@PathVariable Integer PageSize){
        System.out.println("get");
        List<User> users = ....
        return users;
    }
}