Here is an example validator for bean class User.
RegisterAction-validation.xml
1 <?xml version="1.0" encoding="GBK"?>
2 <!DOCTYPE validators PUBLIC "-//OpenSymphony Group//XWork Validator 1.0.2//EN"
3 "http://www.opensymphony.com/xwork/xwork-validator-1.0.2.dtd">
4 <validators>
5 <field name="name">
6 <field-validator type="requiredstring" short-circuit="true">
7 <message>Name is null!</message>
8 </field-validator>
9
10 <field-validator type="regex">
11 <!-- 必须匹配正则表达式：只能是字母和数字，且长度必须在4到25之间 -->
12 <param name="expression"><![CDATA[(\w{4,25})]]></param>
13 <message>Your name must only have english characters and digits, length from 4 to 25.</message>
14 </field-validator>
15 </field>
16
17
18 <field name="password">
19 <field-validator type="requiredstring" short-circuit="true">
20 <param name="trim">true</param>
21 <message>Password is missing!</message>
22 </field-validator>
23 <field-validator type="regex">
24 <param name="expression"><![CDATA[(\w{4,25})]]></param>
25 <message>Password can only have english characters, length from 4 to 25.</message>
26 </field-validator>
27 </field>
28
29 <field name="age">
30 <field-validator type="int"> <!--必须在指定范围内-->
31 <param name="min">1</param>
32 <param name="max">150</param>
33 <message>Age can only between 1 and 150.</message>
34 </field-validator>
35 </field>
36 </validators>
field name="name" "password" and "age" are 3 variables in RegisterAction.java. They can be like this way:
1 package com.googlesites.qslbinghamton.xmlexamples;
2
3 import com.opensymphony.xwork2.ActionSupport;
4
5 public class RegisterAction extends ActionSupport {
6 private String name;
7 private String password;
8 private int age;
9 public String getName() {
10 return name;
11 }
12 public void setName(String name) {
13 this.name = name;
14 }
15 public String getPassword() {
16 return password;
17 }
18 public void setPassword(String password) {
19 this.password = password;
20 }
21 public int getAge() {
22 return age;
23 }
24 public void setAge(int age) {
25 this.age = age;
26 }
27 @Override
28 public String execute() throws Exception {
29 /**
30 * Save user by creating user object
31 *
32 * User user = new User();
33 * user.setName(name);
34 * user.setPassword(password);
35 * user.setAge(age);
36 *
37 * userService.save(user);
38 * */
39 return SUCCESS;
40 }
41 }
Other than this, struts2 have OO oriented, thus ***-validation.xml can be changed such as in field name="user.username"
RegisterAction-validation.xml
1 <?xml version="1.0" encoding="GBK"?>
2 <!DOCTYPE validators PUBLIC "-//OpenSymphony Group//XWork Validator 1.0.2//EN"
3 "http://www.opensymphony.com/xwork/xwork-validator-1.0.2.dtd">
4 <validators>
5 <field name="user.name">
6 <field-validator type="requiredstring" short-circuit="true">
7 <message>Name is null!</message>
8 </field-validator>
9
10 <field-validator type="regex">
11 <!-- 必须匹配正则表达式：只能是字母和数字，且长度必须在4到25之间 -->
12 <param name="expression"><![CDATA[(\w{4,25})]]></param>
13 <message>Your name must only have english characters and digits, length from 4 to 25.</message>
14 </field-validator>
15 </field>
16
17
18 <field name="user.password">
19 <field-validator type="requiredstring" short-circuit="true">
20 <param name="trim">true</param>
21 <message>Password is missing!</message>
22 </field-validator>
23 <field-validator type="regex">
24 <param name="expression"><![CDATA[(\w{4,25})]]></param>
25 <message>Password can only have english characters, length from 4 to 25.</message>
26 </field-validator>
27 </field>
28
29 <field name="user.age">
30 <field-validator type="int"> <!--必须在指定范围内-->
31 <param name="min">1</param>
32 <param name="max">150</param>
33 <message>Age can only between 1 and 150.</message>
34 </field-validator>
35 </field>
36 </validators>
RegisterAction.java can only have User user as a member variable without String name, String password, int age separatedly.
The advantage is quite clear.
1 package com.googlesites.qslbinghamton.xmlexamples;
2
3 import com.opensymphony.xwork2.ActionSupport;
4
5 public class RegisterAction extends ActionSupport {
6 private User user;
7
8 public User getUser() {
9 return user;
10 }
11
12 public void setUser(User user) {
13 this.user = user;
14 }
15
16 @Override
17 public String execute() throws Exception {
18 /**
19 * Save user by creating user object:
20 *
21 * userService.save(user);
22 * */
23 return SUCCESS;
24 }
25 }
26
Also, take a loot at class User, as xxxAction-validation.xml can show that User has name, password and age as its attributes.
1 public class User {
2 private long id;
3 private String name;
4 private String password;
5 private int age;
6 public long getId() {
7 return id;
8 }
9 public void setId(long id) {
10 this.id = id;
11 }
12 public String getName() {
13 return name;
14 }
15 public void setName(String name) {
16 this.name = name;
17 }
18 public String getPassword() {
19 return password;
20 }
21 public void setPassword(String password) {
22 this.password = password;
23 }
24 public int getAge() {
25 return age;
26 }
27 public void setAge(int age) {
28 this.age = age;
29 }
30 }
Attribute id will be created automatically when insert user into database, therefore, there's no need to create input or validator for id.
Now, let me review all common validator's type and their configuration one by one:
1. Must have a input validator
1 <!-- Must have input -->
2 <validators>
3 <field name="username">
4 <field-validator type="required">
5 <message>must have input</message>
6 </field-validator>
7 </field>
8 </validators>
2. Must hava a String input validator
1 <!-- Must have String input -->
2 <validators>
3 <field name="username">
4 <field-validator type="requiredstring">
5 <param name="trim">true</param> <!-- trim the space before and after string input -->
6 <message>Must have string input</message>
7 </field-validator>
8 </field>
9 </validators>
3. Integer/Float validator
1 <!-- valid integer or float check -->
2 <validators>
3 <field name="age">
4 <field-validator type="int">
5 <param name="min">1</param>
6 <param name="max">150</param>
7 <message>Age must be in range from 1 to 150</message>
8 </field-validator>
9 </field>
10 </validators>
4. Date validator
1 <!-- valid date check -->
2 <validators>
3 <field name="birth">
4 <field-validator type="date">
5 <param name="min">1900-01-01</param>
6 <param name="max">2050-02-21</param>
7 <message key="birth.range" />
8 </field-validator>
9 </field>
10 </validators>
5. Regular expression validator
1 <!-- valid regular expression check -->
2 <validators>
3 <field name="username">
4 <field-validator type="regex">
5 <!-- Must match regular expression: english character, 4 to 25 -->
6 <param name="expression"><![CDATA[(\w{4,25})]]></param>
7 <message>Your name must only have english characters and digits, length from 4 to 25.</message>
8 </field-validator>
9 </field>
10 </validtors>
6. Password validator
1 <!-- valid integer or float check -->
2 <validators>
3 <field name="age">
4 <field-validator type="int">
5 <param name="min">1</param>
6 <param name="max">150</param>
7 <message>Age must be in range from 1 to 150</message>
8 </field-validator>
9 </field>
10 </validators>
Notice: must have both String password and String repassword in ***Action.java
7. Email address validator
1 <!-- valid email -->
2 <validators>
3 <field name="email">
4 <field-validator type="email">
5 <message>Must be a valid email address</message>
6 </field-validator>
7 </field>
8 </validators>
8. URL address validator
1 <!-- valid url -->
2 <validators>
3 <field name="url">
4 <field-validator type="url">
5 <message>Must be a valid url address</message>
6 </field-validator>
7 </field>
8 </validators>
9. String length validator
1 <!-- String length check -->
2 <validators>
3 <field name="username">
4 <field-validator type="stringlength">
5 <param name="minlength">4</param>
6 <param name="maxlength">20</param>
7 <message>username must between length 4 and 20 characters</message>
8 </field-validator>
9 </field>
10 </validators>
10. type="visitor" validator
When there's only User user object in ***.java which extends ActionSupport.
***-validation.xml can be: (*** is the name as ***.java)
RegisterAction-validation.xml
1 <!-- Vistor -->
2 <validators>
3 <field name="user">
4 <field-validator type="visitor">
5 <param name="context">userContext</param>
6 <param name="appendPrefix">true</param>
7 <message>Input error：</message>
8 </field-validator>
9 </field>
10 </validators>
Also create User-userContext-validation.xml under the same package with User bean:
***-*****-validation.xml's naming rule: *** must be the bean's name such as User;
***** must be the value from <param name="context">*****</param> in ****-validation.xml
User-userContext-validation.xml
1 <?xml version="1.0" encoding="UTF-8"?>
2
3 <!DOCTYPE validators PUBLIC
4 "-//OpenSymphony Group//XWork Validator 1.0//EN"
5 "http://www.opensymphony.com/xwork/xwork-validator-1.0.2.dtd">
6 <validators>
7 <field name="name">
8 <field-validator type="requiredstring">
9 <param name="trim">true</param>
10 <message>必须输入名字</message>
11 </field-validator>
12 <field-validator type="regex">
13 <param name="expression"><![CDATA[(\w{4,25})]]></param>
14 <message>您输入的用户名只能是字母和数组，且长度必须在4到25之间</message>
15 </field-validator>
16 </field>
17 <field name="password">
18 <field-validator type="requiredstring">
19 <param name="trim">true</param>
20 <message>必须输入密码</message>
21 </field-validator>
22 <field-validator type="regex">
23 <param name="expression"><![CDATA[(\w{4,25})]]></param>
24 <message>您输入的密码只能是字母和数组，且长度必须在4到25之间</message>
25 </field-validator>
26 </field>
27 <field name="age">
28 <field-validator type="int">
29 <param name="min">1</param>
30 <param name="max">150</param>
31 <message>年纪必须在1到150之间</message>
32 </field-validator>
33 </field>
34 <field name="birth">
35 <field-validator type="date">
36 <param name="min">1900-01-01</param>
37 <param name="max">2050-02-21</param>
38 <message>年纪必须在${min}到${max}之间</message>
39 </field-validator>
40 </field>
41 </validators>