Grails Date解组

Question

如果我从RESTful客户端获得以下json,我如何优雅地解组java.util.Date？(有可能不提供(也就是硬编码)格式,这就是我的优雅意思......)

{
  "class": "url",
  "link": "http://www.empa.ch",
  "rating": 5,
  "lastcrawl" : "2009-06-04 16:53:26.706 CEST",
  "checksum" : "837261836712xxxkfjhds",
}

Answer 1

最干净的方法可能是为可能的日期格式注册自定义DataBinder.

import java.beans.PropertyEditorSupport;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class CustomDateBinder extends PropertyEditorSupport {

    private final List<String> formats;

    public CustomDateBinder(List formats) {
        List<String> formatList = new ArrayList<String>(formats.size());
        for (Object format : formats) {
            formatList.add(format.toString()); // Force String values (eg. for GStrings)
        }
        this.formats = Collections.unmodifiableList(formatList);
    }

    @Override
    public void setAsText(String s) throws IllegalArgumentException {
        if (s != null)
            for (String format : formats) {
                // Need to create the SimpleDateFormat every time, since it's not thead-safe
                SimpleDateFormat df = new SimpleDateFormat(format);
                try {
                    setValue(df.parse(s));
                    return;
                } catch (ParseException e) {
                    // Ignore
                }
            }
    }
}

您还需要实现PropertyEditorRegistrar

import org.springframework.beans.PropertyEditorRegistrar;
import org.springframework.beans.PropertyEditorRegistry;

import grails.util.GrailsConfig;
import java.util.Date;
import java.util.List;

public class CustomEditorRegistrar implements PropertyEditorRegistrar {
    public void registerCustomEditors(PropertyEditorRegistry reg) {
        reg.registerCustomEditor(Date.class, new CustomDateBinder(GrailsConfig.get("grails.date.formats", List.class)));
    }
}          

并在你的grails-app/conf/spring/resources.groovy中创建一个Spring-bean定义:

beans = {
    "customEditorRegistrar"(CustomEditorRegistrar)
}

最后在grails-app/conf/Config.groovy中定义日期格式:

grails.date.formats = ["yyyy-MM-dd HH:mm:ss.SSS ZZZZ", "dd.MM.yyyy HH:mm:ss"]

Answer 2

请注意,新版本的Grails 2.3+支持开箱即用的此类功能.请参阅数据绑定的日期格式

话虽如此,如果您被迫使用2.3之前的Grails版本,CustomEditorRegistrar 可以使用以下代码更新以消除弃用警告,并且还使用@Component注释,这允许您删除/跳过添加豆直接进入resources.groovy.也不是我将grails配置属性名称更改为grails.databinding.dateFormats,它与Grails 2.3+中现在支持的属性相匹配.最后,我的版本是.groovy,而不是.java文件.

import javax.annotation.Resource
import org.codehaus.groovy.grails.commons.GrailsApplication
import org.springframework.beans.PropertyEditorRegistrar
import org.springframework.beans.PropertyEditorRegistry
import org.springframework.stereotype.Component

@Component
public class CustomEditorRegistrar implements PropertyEditorRegistrar {

    @Resource
    GrailsApplication grailsApplication

    public void registerCustomEditors(PropertyEditorRegistry reg){
        def dateFormats = grailsApplication.config.grails.databinding.dateFormats as List
        reg.registerCustomEditor(Date.class, new CustomDateBinder(dateFormats))
    }
}