[Turn] SpringMVC returns the date format of json when using @ResponseBody, pay attention to the use of @DatetimeFormat

1. SpringMVC returns the date format of json when using @ResponseBody

Prerequisites: @ResponseBody The core class that returns json strings is org.springframework.http.converter.json.MappingJacksonHttpMessageConverter, which uses Jackson, an open source third-party library. Mainly the following two jar packages: jackson-core-asl-1.6.4.jar; jackson-mapper-asl-1.6.4.jar.

Problem arises: Date format returned as json string when using @ResponseBody. The Date type attribute returns a Long timestamp by default. How can I return a custom date format?

Solution: There are currently two ways to achieve,

1. Partial modification (there are many online, but not recommended);

Inherit Jackson's abstract class: JsonSerializer<T>, and then add the annotation @JsonSerialize to the property getter() of the javabean to achieve this.

code show as below:

    Java code   
    
  
import java.io.IOException;  
import java.text.SimpleDateFormat;  
import java.util.Date;  
  
import org.codehaus.jackson.JsonGenerator;  
import org.codehaus.jackson.JsonProcessingException;  
import org.codehaus.jackson.map.JsonSerializer;  
import org.codehaus.jackson.map.SerializerProvider;  
  
/** 
 * @description Customize the date formatting processing in the returned JSON data grid 
 * @author aokunsang 
 * @date 2013-5-28 
 */  
public class CustomDateSerializer extends JsonSerializer<Date> {  
  
    @Override  
    public void serialize(Date value,   
            JsonGenerator jsonGenerator,   
            SerializerProvider provider)  
            throws IOException, JsonProcessingException {  
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");  
        jsonGenerator.writeString(sdf.format(value));  
    }  
}  

How to use:

    Java code   
    
  
@JsonSerialize(using = CustomDateSerializer.class)  
public Date getCreateDate() {  
    return createDate;  
}  

2、全局修改(强烈推荐)：

MappingJacksonHttpMessageConverter主要通过ObjectMapper来实现返回json字符串。这里我们继承该类，注册一个JsonSerializer<T>。然后在配置文件中注入自定义的ObjectMapper。

代码如下：

    Java代码   
    
  
import java.io.IOException;  
import java.text.SimpleDateFormat;  
import java.util.Date;  
  
import org.codehaus.jackson.JsonGenerator;  
import org.codehaus.jackson.JsonProcessingException;  
import org.codehaus.jackson.map.JsonSerializer;  
import org.codehaus.jackson.map.ObjectMapper;  
import org.codehaus.jackson.map.SerializerProvider;  
import org.codehaus.jackson.map.ser.CustomSerializerFactory;  
  
/** 
 * @description 解决Date类型返回json格式为自定义格式 
 * @author aokunsang 
 * @date 2013-5-28 
 */  

public class CustomObjectMapper extends ObjectMapper {  
  
    public CustomObjectMapper(){  
        CustomSerializerFactory factory = new CustomSerializerFactory();  
        factory.addGenericMapping(Date.class, new JsonSerializer<Date>(){  
            @Override  
            public void serialize(Date value,   
                    JsonGenerator jsonGenerator,   
                    SerializerProvider provider)  
                    throws IOException, JsonProcessingException {  
                SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");  
                jsonGenerator.writeString(sdf.format(value));  
            }  
        });  
        this.setSerializerFactory(factory);  
    }  
}  

spring-servlet.xml中配置：

    Java代码   
    
  
<mvc:annotation-driven>  
        <mvc:message-converters>  
            <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">  
                <property name="objectMapper" ref="customObjectMapper"></property>  
            </bean>  
        </mvc:message-converters>  
    </mvc:annotation-driven>  
   <bean id="customObjectMapper" class="com.pmc.dwa.common.custom.CustomObjectMapper"></bean> 

Second, the use of @DatetimeFormat attention

1. It is very simple to use @DatetimeFormat. It should be noted here that a class library joda-time-1.3.jar should be introduced when using it, otherwise the corresponding path will not be accessible (400 error).

ps: This annotation can be used at the METHOD, FIELD and PARAMETER levels.

Use introduction reference: http://www.captaindebug.com/2011/08/using-spring-3-datetimeformat.html#.UaR3mWWZk0k

2. Because springMVC does not provide a default date converter, how to convert the date string passed from the previous page to a date type? If there is no global date converter or data binding, you can use the @DatetimeFormat annotation to complete.

[Turn] SpringMVC returns the date format of json when using @ResponseBody, pay attention to the use of @DatetimeFormat

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