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## 1. 基本数据类型(以int为例,其他类似): Controller代码: ~~~ @RequestMapping("saysth.do") public void test(int count) { } ~~~ 表单代码: ~~~ <form action="saysth.do" method="post"> <input name="count" value="10" type="text"/> ...... </form> ~~~ 1. 表单中input的name值和Controller的参数变量名保持一致,就能完成数据绑定 2. 如果不一致可以使用@RequestParam注解指定表单中的参数名,此时controller中方法参数可以随便写了(反正由注解指定了与表单中放入参数绑定)。 3. 需要注意的是,如果Controller方法参数中定义的是基本数据类型,`但是从页面提交过来的数据为null或者”"的话,会出现数据转换的异常`。也就是必须保证表单传递过来的数据不能为null或”",所以,在开发过程中,对可能为空的数据,最好将参数数据类型定义成包装类型,具体参见下面的例子。 ## 2. 包装类型(以Integer为例,其他类似): Controller代码: ~~~ @RequestMapping("saysth.do") public void test(Integer count) { } ~~~ 表单代码: ~~~ <form action="saysth.do" method="post"> <input name="count" value="10" type="text"/> ...... </form> ~~~ 1. 和基本数据类型基本一样,不同之处在于,表单传递过来的数据可以为null或”"(controller不抛异常),以上面代码为例,如果表单中num为”"或者表单中无num这个input,那么,Controller方法参数中的num值则为null。 ## 3. 自定义对象类型: Model代码: ~~~ public class User { private String firstName; private String lastName; 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; } } ~~~ Controller代码: ~~~ @RequestMapping("saysth.do") public void test(User user) { } ~~~ 表单代码: ~~~ <form action="saysth.do" method="post"> <input name="firstName" value="张" type="text"/> <input name="lastName" value="三" type="text"/> ...... </form> ~~~ 1. 非常简单,只需将对象的属性名和input的name值一一匹配即可。 ## 4. 自定义复合对象类型: Model代码: ~~~ public class ContactInfo { private String tel; private String address; public String getTel() { return tel; } public void setTel(String tel) { this.tel = tel; } public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } } ~~~ ~~~ public class User { private String firstName; private String lastName; private ContactInfo contactInfo; 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 ContactInfo getContactInfo() { return contactInfo; } public void setContactInfo(ContactInfo contactInfo) { this.contactInfo = contactInfo; } } ~~~ Controller代码: ~~~ @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()); } ~~~ 表单代码: ~~~ <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> ~~~ 1. 原则与上边一样,对象属性名与表单name值一样就行 2. 对象中的对象,对应表单name值为 对象2.对象2的值,例如contactInfo.tel ## 5. List绑定: List需要绑定在对象上,而不能直接写在Controller方法的参数中。 Model代码: ~~~ public class User { private String firstName; private String lastName; 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 class UserListForm { private List<User> users; public List<User> getUsers() { return users; } public void setUsers(List<User> users) { this.users = users; } } ~~~ Controller代码: ~~~ @RequestMapping("saysth.do") public void test(UserListForm userForm) { for (User user : userForm.getUsers()) { System.out.println(user.getFirstName() + " - " + user.getLastName()); } } ~~~ 表单代码: ~~~ <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> ~~~ 1. input框中name值,与包装类userForm中list变量名相同,就把User的数据填进去了 表单代码: ~~~ <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[20].firstName" value="eee" /></td> <td><input name="users[20].lastName" value="fff" /></td> </tr> </tbody> </table> </form> ~~~ 这个时候,Controller中的userForm.getUsers()获取到List的size为21,而且这21个User对象都不会为null,但是,第2到第19的User对象中的firstName和lastName都为null。打印结果: ~~~ aaa - bbb ccc - ddd null - null null - null null - null null - null null - null null - null null - null null - null null - null null - null null - null null - null null - null null - null null - null null - null null - null null - null eee - fff ~~~ ## 6. Set绑定: Set和List类似,也需要绑定在对象上,而不能直接写在Controller方法的参数中。但是,绑定Set数据时,必须先在Set对象中add相应的数量的模型对象。 Model代码: ~~~ public class User { private String firstName; private String lastName; 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 class UserSetForm { private Set<User> users = new HashSet<User>(); public UserSetForm() { users.add(new User()); users.add(new User()); users.add(new User()); } public Set<User> getUsers() { return users; } public void setUsers(Set<User> users) { this.users = users; } } ~~~ Controller代码: ~~~ @RequestMapping("saysth.do") public void test(UserSetForm userForm) { for (User user : userForm.getUsers()) { System.out.println(user.getFirstName() + " - " + user.getLastName()); } } ~~~ 表单代码: ~~~ <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> ~~~ 基本和List绑定类似。 需要特别提醒的是,如果最大下标值大于Set的size,则会抛出org.springframework.beans.InvalidPropertyException异常。所以,在使用时有些不便。 7. Map绑定: Map最为灵活,它也需要绑定在对象上,而不能直接写在Controller方法的参数中。 Model代码: ~~~ public class User { private String firstName; private String lastName; 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 class UserMapForm { private Map<String, User> users; public Map<String, User> getUsers() { return users; } public void setUsers(Map<String, User> users) { this.users = users; } } ~~~ Controller代码: ~~~ @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()); } } ~~~ 表单代码: ~~~ <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> ~~~ 打印结果: x: aaa - bbb y: ccc - ddd z: eee - fff