SpringMVC 如何定义类型转换器

举例说明， 将一个字符串转换成的 User 类型。

例如将字符串 1-zcd-1234-zcd@163.com-1999/12/12  转换成User 类型。

一、实体类

public class User
{
    private Integer id;
    private String name;
    private Integer money;
    private String email;

    private Date birth;

    //构造器 、getter 、setter 方法省略　　
}

二、Controller 

@Controller
@RequestMapping(value="testHiddenHttpMethodFilter")
public class TestHiddenHttpMethodFilter
{
    @RequestMapping(value="dataConvertAndFormat", method=RequestMethod.GET)
    public String dataConvertAndFormat(Map<String, Object> map)
    {
        map.put("user", new User());
        
        return "testMethod";
    }
    
    @RequestMapping(value="testConverter", method=RequestMethod.POST)
    public String testConverter(User user)
    {
        System.out.println("进入testConverter");
        
        System.out.println(user);
        return "success";
    }
    
}

在表单中输入一个字符串 1-zcd-1234-zcd@163.com-1999/12/12 

<form
        action="${pageContext.request.contextPath}/testHiddenHttpMethodFilter/testConverter"
        method="POST" >
        
        User:<input type="text" name="user">
        
        <br>
        <input type="submit" name="Submit" value="提交">
        <br>
    </form>

下面的代码没有考虑异常情况，比如说不进行数字转换，日期转换等等。仅仅考虑正确的情况。

@Component
public class UserConverter implements Converter<String, User>
{

    @Override
    public User convert(String source)
    {
        User user = new User();
        
        String[] vals = source.split("-");
        System.out.println(source);
        System.out.println(vals);
        
        for (String s : vals)
        {
            Integer id = Integer.valueOf(vals[0]);
            String name = vals[1];
            Integer money = Integer.valueOf(vals[2]);
            String email = vals[3];
            Date birth = new Date(vals[4]);
            
            user.setId(id);
            user.setName(name);
            user.setMoney(money);
            user.setEmail(email);
            user.setBirth(birth);
        }
        
        return user;
    }
    
}

最后还要在SpringMVC的配置文件中配置一下

<!-- 扫描包 -->
    <context:component-scan base-package="com.zcd.springmvc"></context:component-scan>
    
    <!-- 配置视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/views/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>
    
    <mvc:default-servlet-handler/>
    
　　 //进行一下配置
    <mvc:annotation-driven conversion-service="conversionService" ></mvc:annotation-driven>
    
    <bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean">
        <property name="converters">
            <set>
                <ref bean="userConverter" />
            </set>
        </property>
    </bean>