Spring MVC provides several ways that a client can pass data into a controller’s handler method. These include
1. Query parameters
2. Form parameters
3. Path variables
1. Query parameters
/spittles/max=100&count=30
<span style="font-size:14px;">@RequestMapping(method=RequestMethod.GET)
public List<Spittle> spittles(
@RequestParam(value="max", defaultValue=MAX_LONG_AS_STRING) long max,
@RequestParam(value="count", defaultValue="20") int count) {
return spittleRepository.findSpittles(max, count);
}</span>
2. Path variables
/spittles/12345
<span style="font-size:14px;">@RequestMapping(value="/{spittleId}", method=RequestMethod.GET)
public String spittle(
@PathVariable("spittleId") long spittleId,
Model model) {
model.addAttribute(spittleRepository.findOne(spittleId));
return "spittle";
}</span>
两者的区别：
Ideally, the resource being identified (the Spittle) would be identified by the URL path, not by query parameters. As a general rule, query parameters should not be used to identify a resource. A GET request for /spittles/12345 is better than one for /spittles/show?spittle_id=12345. The former identifies a resource to be retrieved. The latter describes an operation with a parameter—essentially RPC over HTTP.
意思是如果是面向资源的就采用Path variables的方式，如果是通过HTTP方式调用后台逻辑的就采用Query parameters方式.
3. Form submit
@RequestMapping(value = "/register", method = POST)
public String processRegistration(@Valid <strong>Spitter</strong> spitter, Errors errors) {
if (errors.hasErrors()) {
return "registerForm";
}
spitterRepository.save(spitter);
return "redirect:/spitter/" + spitter.getUsername();
}
Spring框架自动将窗体提交的数据转换为Spitter对象。当然Form中的相应属性需要与对象的属性保持一致。
View source code:
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ page session="false" %>
<html>
<head>
<title>Spittr</title>
<link rel="stylesheet" type="text/css"
href="<c:url value="/resources/style.css" />" >
</head>
<body>
<h1>Register</h1>
<form method="POST">
First Name: <input type="text" name="firstName" /><br/>
Last Name: <input type="text" name="lastName" /><br/>
Username: <input type="text" name="username" /><br/>
Password: <input type="password" name="password" /><br/>
<input type="submit" value="Register" />
</form>
</body>
</html>
Object source code:
package spittr;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import org.apache.commons.lang3.builder.EqualsBuilder;
import org.apache.commons.lang3.builder.HashCodeBuilder;
import org.hibernate.validator.constraints.Email;
public class Spitter {
private Long id;
@NotNull
@Size(min=5, max=16)
private String username;
@NotNull
@Size(min=5, max=25)
private String password;
@NotNull
@Size(min=2, max=30)
private String firstName;
@NotNull
@Size(min=2, max=30)
private String lastName;
@NotNull
@Email
private String email;
public Spitter() {}
public Spitter(String username, String password, String firstName, String lastName, String email) {
this(null, username, password, firstName, lastName, email);
}
public Spitter(Long id, String username, String password, String firstName, String lastName, String email) {
this.id = id;
this.username = username;
this.password = password;
this.firstName = firstName;
this.lastName = lastName;
this.email = email;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
@Override
public boolean equals(Object that) {
return EqualsBuilder.reflectionEquals(this, that, "firstName", "lastName", "username", "password", "email");
}
@Override
public int hashCode() {
return HashCodeBuilder.reflectionHashCode(this, "firstName", "lastName", "username", "password", "email");
}
}
