Backend

Spring参数绑定

Spring

参数绑定相关注解

  1. @RequestParam，绑定单个请求数据，可以是URL中的数据，表单提交的数据或上传的文件；
  2. @PathVariable，绑定URL模板变量值；
  3. @CookieValue，绑定Cookie数据；
  4. @RequestHeader，绑定请求头数据；
  5. @ModelAttribute，绑定数据到Model；
  6. @SessionAttributes，绑定数据到Session；
  7. @RequestBody，用来处理Content-Type不是application/x-www-form-urlencoded编码的内容，例如application/json, application/xml等；
  8. @RequestPart，绑定“multipart/data”数据，并可以根据数据类型进项对象转换；

基本数据类型-int

如果参数的属性是required的, 可以用int. 如果不是required的, 需要使用包装类型Integer. 因为值为null会导致异常.

  • Controller
@RequestMapping("saysth.do")
public void test(int count) {
}
  • form
<form action="saysth.do" method="post">
	<input name="count" value="10" type="text"/>
</form>
`

包装类型-integer

  • Controller
@RequestMapping("saysth.do")
public void test(Integer count) {
}
  • HTML
    <form action="saysth.do" method="post">
        <input name="count" value="10" type="text"/>
    </form>
    `

自定义对象类型

  • Model
public class User {
    private String firstName;
    private String lastName;
  ...
}
  • Controller
@RequestMapping("saysth.do")
public void test(User user) {
}
  • HTML
    <form action="saysth.do" method="post">
        <input name="firstName" value="张" type="text"/>
        <input name="lastName" value="三" type="text"/>
    </form>

自定义复合对象类型

  • Model
public class ContactInfo {
    private String tel;
    private String address;
    public String getTel() {
        return tel;
    }
    ...
}
public class User {
    private String firstName;
    private String lastName;
    private ContactInfo contactInfo;
    ... getter & setter
}
  • Controller
@RequestMapping("saysth.do")
public void test(User user) {
    System.out.println(user.getFirstName());
    System.out.println(user.getLastName());
    System.out.println(user.getContactInfo().getTel());
    System.out.println(user.getContactInfo().getAddress());
}
  • HTML
<form action="saysth.do" method="post">
	<input name="firstName" value="张" /><br>
	<input name="lastName" value="三" /><br>
	<input name="contactInfo.tel" value="13809908909" /><br>
	<input name="contactInfo.address" value="北京海淀" /><br>
	<input type="submit" value="Save" />
</form>

List

  • Model
public class User {
    private String firstName;
    private String lastName;
    ...
}
public class UserListForm {
    private List<User> users;
    ...
}
  • Controller
@RequestMapping("saysth.do")
public void test(UserListForm userForm) {
    for (User user : userForm.getUsers()) {
        System.out.println(user.getFirstName() + " - " + user.getLastName());
    }
}
  • HTML
<form action="saysth.do" method="post">
	<table>
		<thead>
			<tr>
				<th>First Name</th>
				<th>Last Name</th>
			</tr>
		</thead>
		<tfoot>
			<tr>
				<td colspan="2"><input type="submit" value="Save" /></td>
			</tr>
		</tfoot>
		<tbody>
			<tr>
				<td><input name="users[0].firstName" value="aaa" /></td>
				<td><input name="users[0].lastName" value="bbb" /></td>
			</tr>
			<tr>
				<td><input name="users[1].firstName" value="ccc" /></td>
				<td><input name="users[1].lastName" value="ddd" /></td>
			</tr>
			<tr>
				<td><input name="users[2].firstName" value="eee" /></td>
				<td><input name="users[2].lastName" value="fff" /></td>
		</tr>
		</tbody>
	</table>
</form>

Set

  • Model
public class User {
    private String firstName;
    private String lastName;
    ...
}
public class UserSetForm {
    private Set<User> users = new HashSet<User>();
    public UserSetForm() {
        users.add(new User());
        users.add(new User());
        users.add(new User());
    }
    ...
}
  • Controller
@RequestMapping("saysth.do")
public void test(UserSetForm userForm) {
    for (User user : userForm.getUsers()) {
        System.out.println(user.getFirstName() + " - " + user.getLastName());
    }
}
  • HTML
<form action="saysth.do" method="post">
	<table>
		<thead>
			<tr>
				<th>First Name</th>
				<th>Last Name</th>
			</tr>
		</thead>
		<tfoot>
			<tr>
				<td colspan="2"><input type="submit" value="Save" /></td>
			</tr>
		</tfoot>
		<tbody>
			<tr>
				<td><input name="users[0].firstName" value="aaa" /></td>
				<td><input name="users[0].lastName" value="bbb" /></td>
			</tr>
			<tr>
				<td><input name="users[1].firstName" value="ccc" /></td>
				<td><input name="users[1].lastName" value="ddd" /></td>
			</tr>
			<tr>
				<td><input name="users[2].firstName" value="eee" /></td>
				<td><input name="users[2].lastName" value="fff" /></td>
			</tr>
		</tbody>
	</table>
</form>

Map

  • Model
public class User {
    private String firstName;
    private String lastName;
    ...
}
public class UserMapForm {
    private Map<String, User> users;
    ...
}
  • Controller
@RequestMapping("saysth.do")
public void test(UserMapForm userForm) {
    for (Map.Entry<String, User> entry : userForm.getUsers().entrySet()) {
        System.out.println(entry.getKey() + ": " + entry.getValue().getFirstName() + " - " +
        entry.getValue().getLastName());
    }
}
  • HTML
<form action="saysth.do" method="post">
	<table>
		<thead>
			<tr>
				<th>First Name</th>
				<th>Last Name</th>
			</tr>
		</thead>
		<tfoot>
			<tr>
				<td colspan="2"><input type="submit" value="Save" /></td>
			</tr>
		</tfoot>
		<tbody>
			<tr>
				<td><input name="users['x'].firstName" value="aaa" /></td>
				<td><input name="users['x'].lastName" value="bbb" /></td>
			</tr>
			<tr>
				<td><input name="users['y'].firstName" value="ccc" /></td>
				<td><input name="users['y'].lastName" value="ddd" /></td>
			</tr>
			<tr>
				<td><input name="users['z'].firstName" value="eee" /></td>
				<td><input name="users['z'].lastName" value="fff" /></td>
			</tr>
		</tbody>
	</table>
</form>

Json

前端的content type: contentType:’application/json;charset=utf-8’
controller方法的参数使用@RequestBody

  • Model
public class User {
    private String firstName;
    private String lastName;
  ...
}
  • Controller
@RequestMapping("json.do")
public void test(@RequestBody User user) {
  return user;
}
  • HTML
var params = {
    "firstName": "张",
    "lastName": "三",   
};
$.ajax({
    type: 'post',
    url: 'json.do',
    contentType:'application/json;charset=utf-8',
    dataType: 'json',
    data: JSON.stringify(params),
    success: function(data){
        console.log(data);
    }
});

XML

  • pom.xml
<dependency>
	<groupId>com.fasterxml.jackson.dataformat</groupId>
	<artifactId>jackson-dataformat-xml</artifactId>
</dependency>
  • Model
public class User {
    private String firstName;
    private String lastName;
  ...
}
  • Controller
@RequestMapping("xml.do")
public void xml(@RequestBody User user) {
  return user;
}
  • Postman
POST /xml HTTP/1.1
Host: localhost:8080
Content-Type: application/xml
Cache-Control: no-cache
Postman-Token: 03933f48-c29b-bfb8-bb10-29ed5c2c237c
<user>
	<firstName>张</firstName>
	<lastName>三</lastName>
</user>
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