请求参数的绑定、自定义类型转换器
作者：互联网
请求参数的绑定说明
1.绑定机制
只需要在方法中的参数写上变量名与参数名相同的形参，即可自动获取。
底层实现：通过反射获取形参的名字，再如servlet那样通过request获取参数。
2.支持的数据类型
基本数据类型和字符串类型
实体类型(JavaBean)
集合数据类型(List、map集合等)
封装JavaBean
Account类(其中包含User类)
package com.czy.domain;
import java.io.Serializable;
public class Account implements Serializable {
private String username;
private String password;
private Double money;
private User user;
public User getUser() {
return user;
}
@Override
public String toString() {
return "Account{" +
"username='" + username + '\'' +
", password='" + password + '\'' +
", money=" + money +
", user=" + user +
'}';
}
public void setUser(User user) {
this.user = user;
}
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 Double getMoney() {
return money;
}
public void setMoney(Double money) {
this.money = money;
}
}
User类
package com.czy.domain;
import java.io.Serializable;
public class User implements Serializable {
private String uname;
private Integer age;
@Override
public String toString() {
return "User{" +
"uname='" + uname + '\'' +
", age=" + age +
'}';
}
public String getUname() {
return uname;
}
public void setUname(String uname) {
this.uname = uname;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
表单(注意user的项目)
<form method="post" action="param/saveAccount">
<label for="username">姓名:</label>
<input id="username" name="username"><br>
<label for="password">密码:</label>
<input type="password" name="password" id="password"><br>
<label for="money">金额:</label>
<input type="text" id="money" name="money"><br>
<label for="uname">用户姓名:</label>
<input id="uname" name="user.uname"><br> <!--user.uname封装进user中-->
<label for="age">用户年龄:</label> <!--同上-->
<input id="age" name="user.age"><br>
<input type="submit" value="提交">
</form>
Controller接收自动封装
@RequestMapping("/saveAccount")
public String saveAccount(Account account){
System.out.println(account);
return "success";
}
集合数据封装
Account类
package com.czy.domain;
import java.io.Serializable;
import java.util.List;
import java.util.Map;
public class Account implements Serializable {
private String username;
private String password;
private Double money;
private List<User> users;
private Map<String,User> map;
public Map<String, User> getMap() {
return map;
}
public void setMap(Map<String, User> map) {
this.map = map;
}
public List<User> getUsers() {
return users;
}
public void setUsers(List<User> users) {
this.users = users;
}
@Override
public String toString() {
return "Account{" +
"username='" + username + '\'' +
", password='" + password + '\'' +
", money=" + money +
", users=" + users +
", map=" + map +
'}';
}
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 Double getMoney() {
return money;
}
public void setMoney(Double money) {
this.money = money;
}
}
前台表单
<form method="post" action="param/saveAccount">
<label for="username">姓名:</label>
<input id="username" name="username"><br>
<label for="password">密码:</label>
<input type="password" name="password" id="password"><br>
<label for="money">金额:</label>
<input type="text" id="money" name="money"><br>
<label for="uname1">用户姓名:</label>
<input id="uname1" name="users[0].uname"><br>
<label for="age1">用户年龄:</label>
<input id="age1" name="users[0].age"><br>
<label for="uname2">用户姓名:</label>
<input id="uname2" name="map['one'].uname"><br>
<label for="age2">用户年龄:</label>
<input id="age2" name="map['one'].age"><br>
<input type="submit" value="提交">
</form>
3.过滤器解决中文乱码
web.xml中配置过滤器
<filter>
<filter-name>characterEncodingFilter</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>characterEncodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
特殊情况——自定义类型转换器
我们从前台的数据提交上来的都是String，MVC通过内置的类型转换器帮我们转换成对应的类型，存入JavaBean/参数中。但是有时某些形式的数据，会导致存储失败，比如说：日期形式2020/2/2可以存储，而2020-2-2无法存储或前台表单type=date也无法存储。
故我们需要自定义类型转换器解决该问题
步骤一：实现Converter接口
package com.czy.utils;
import org.springframework.core.convert.converter.Converter;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
/**
* 把字符串转换为日期
*/
public class StringToDateConverter implements Converter<String, Date> {
@Override
public Date convert(String s) {
if(s == null){
throw new RuntimeException("传参为空");
}
DateFormat format = new SimpleDateFormat("yyyy-MM-dd");
try {
return format.parse(s);
} catch (ParseException exception) {
throw new RuntimeException("数据类型转换错误");
}
}
}
步骤二:注册自定义类型转换器
在springmvc.xml配置文件中配置
<!--开启SpringMVC框架注解的支持-->
<mvc:annotation-driven conversion-service="factoryBean"></mvc:annotation-driven>
<!--配置自定义类型转换器-->
<bean id="factoryBean" class="org.springframework.context.support.ConversionServiceFactoryBean">
<property name="converters">
<set>
<bean class="com.czy.utils.StringToDateConverter"></bean>
</set>
</property>
</bean>
标签：username,return,String,自定义,money,绑定,转换器,password,public 来源： https://www.cnblogs.com/czy-algorithm/p/16221768.html