使用 JSON 将嵌套对象发布到 Spring MVC 控制器 [英] Post Nested Object to Spring MVC controller using JSON
问题描述
我有一个控制器，其 POST 处理程序定义如下:
I have a controller with the POST handler defined like so:
@RequestMapping(value="/ajax/saveVendor.do", method = RequestMethod.POST)
public @ResponseBody AjaxResponse saveVendor( @Valid UIVendor vendor,
BindingResult result,
Locale currentLocale )
UIVendor 对象，当以 JSON 格式查看时，如下所示:
The UIVendor object, when viewed in JSON format, looks like:
var vendor =
{
vendorId: 123,
vendorName: "ABC Company",
emails : [
{ emailAddress: "abc123@abc.com", flags: 2 },
{ emailAddress: "xyz@abc.com", flags: 3 }
]
}
UIVendor bean 有一个名为Emails"的 ArrayList 类型的字段，带有适当的 setter 和 getter (getEmails/setEmails).NotificationEmail 对象也有适当的公共设置器/获取器.
The UIVendor bean has a field called "Emails" of type ArrayList, with appropriate setters and getters (getEmails/setEmails). The NotificationEmail object has the appropriate public setters/getters as well.
当我尝试使用以下代码发布对象时:
When I try to post the object using the following code:
$.post("ajax/saveVendor.do", $.param(vendor), saveEntityCallback, "json" );
我在日志中收到此错误:
I get this error in the logs:
Invalid property 'emails[0][emailAddress]' of bean class [beans.UIVendor]: Property referenced in indexed property path 'emails[0][emailAddress]' is neither an array nor a List nor a Map; returned value was [abc123@abc.com]
如何正确地将这样的嵌套对象发布到 Spring 控制器并使其正确反序列化为适当的对象结构.
How do I correctly post a nested object like this to a Spring controller and have it correctly deserialize into the appropriate object structure.
更新根据 Bohzo 的要求，这里是 UIVendor 类的内容.这个类包装了一个 web 服务生成的 bean 类，将 VendorAttributes 作为单独的字段公开:
UPDATE Per Bohzo's request, here is the content of the UIVendor class. This class wraps a web-service-generated bean class, exposing the VendorAttributes as individual fields:
package com.mycompany.beans;
import java.util.*;
import org.apache.commons.lang.*;
import com.mycompany.domain.Vendor;
import com.mycompany.domain.VendorAttributes;
import org.apache.commons.logging.*;
import org.codehaus.jackson.annotate.JsonIgnore;
public class UIVendor
{
private final Log logger = LogFactory.getLog( this.getClass() );
private Vendor vendor;
private boolean ftpFlag;
private String ftpHost;
private String ftpPath;
private String ftpUser;
private String ftpPassword;
private List<UINotificationEmail> emails = null;
public UIVendor() { this( new Vendor() ); }
public UIVendor( Vendor vendor )
{
this.vendor = vendor;
loadVendorAttributes();
}
private void loadVendorAttributes()
{
this.ftpFlag = false;
this.ftpHost = this.ftpPassword = this.ftpPath = this.ftpUser = "";
this.emails = null;
for ( VendorAttributes a : this.vendor.getVendorAttributes() )
{
String key = a.getVendorFakey();
String value = a.getVendorFaValue();
int flags = a.getFlags();
if ( StringUtils.isBlank(key) || StringUtils.isBlank(value) ) continue;
if ( key.equals( "ftpFlag" ) )
{
this.ftpFlag = BooleanUtils.toBoolean( value );
}
else if ( key.equals( "ftpHost" ) )
{
this.ftpHost = value;
}
else if ( key.equals("ftpPath") )
{
this.ftpPath = value;
}
else if ( key.equals("ftpUser") )
{
this.ftpUser = value;
}
else if ( key.equals("ftpPassword") )
{
this.ftpPassword = value;
}
else if ( key.equals("email") )
{
UINotificationEmail email = new UINotificationEmail(value, flags);
this.getEmails().add( email );
}
}
}
private void saveVendorAttributes()
{
int id = this.vendor.getVendorId();
List<VendorAttributes> attrs = this.vendor.getVendorAttributes();
attrs.clear();
if ( this.ftpFlag )
{
VendorAttributes flag = new VendorAttributes();
flag.setVendorId( id );
flag.setStatus( "A" );
flag.setVendorFakey( "ftpFlag" );
flag.setVendorFaValue( BooleanUtils.toStringTrueFalse( this.ftpFlag ) );
attrs.add( flag );
if ( StringUtils.isNotBlank( this.ftpHost ) )
{
VendorAttributes host = new VendorAttributes();
host.setVendorId( id );
host.setStatus( "A" );
host.setVendorFakey( "ftpHost" );
host.setVendorFaValue( this.ftpHost );
attrs.add( host );
if ( StringUtils.isNotBlank( this.ftpPath ) )
{
VendorAttributes path = new VendorAttributes();
path.setVendorId( id );
path.setStatus( "A" );
path.setVendorFakey( "ftpPath" );
path.setVendorFaValue( this.ftpPath );
attrs.add( path );
}
if ( StringUtils.isNotBlank( this.ftpUser ) )
{
VendorAttributes user = new VendorAttributes();
user.setVendorId( id );
user.setStatus( "A" );
user.setVendorFakey( "ftpUser" );
user.setVendorFaValue( this.ftpUser );
attrs.add( user );
}
if ( StringUtils.isNotBlank( this.ftpPassword ) )
{
VendorAttributes password = new VendorAttributes();
password.setVendorId( id );
password.setStatus( "A" );
password.setVendorFakey( "ftpPassword" );
password.setVendorFaValue( this.ftpPassword );
attrs.add( password );
}
}
}
for ( UINotificationEmail e : this.getEmails() )
{
logger.debug("Adding email " + e );
VendorAttributes email = new VendorAttributes();
email.setStatus( "A" );
email.setVendorFakey( "email" );
email.setVendorFaValue( e.getEmailAddress() );
email.setFlags( e.getFlags() );
email.setVendorId( id );
attrs.add( email );
}
}
@JsonIgnore
public Vendor getVendor()
{
saveVendorAttributes();
return this.vendor;
}
public int getVendorId()
{
return this.vendor.getVendorId();
}
public void setVendorId( int vendorId )
{
this.vendor.setVendorId( vendorId );
}
public String getVendorType()
{
return this.vendor.getVendorType();
}
public void setVendorType( String vendorType )
{
this.vendor.setVendorType( vendorType );
}
public String getVendorName()
{
return this.vendor.getVendorName();
}
public void setVendorName( String vendorName )
{
this.vendor.setVendorName( vendorName );
}
public String getStatus()
{
return this.vendor.getStatus();
}
public void setStatus( String status )
{
this.vendor.setStatus( status );
}
public boolean isFtpFlag()
{
return this.ftpFlag;
}
public void setFtpFlag( boolean ftpFlag )
{
this.ftpFlag = ftpFlag;
}
public String getFtpHost()
{
return this.ftpHost;
}
public void setFtpHost( String ftpHost )
{
this.ftpHost = ftpHost;
}
public String getFtpPath()
{
return this.ftpPath;
}
public void setFtpPath( String ftpPath )
{
this.ftpPath = ftpPath;
}
public String getFtpUser()
{
return this.ftpUser;
}
public void setFtpUser( String ftpUser )
{
this.ftpUser = ftpUser;
}
public String getFtpPassword()
{
return this.ftpPassword;
}
public void setFtpPassword( String ftpPassword )
{
this.ftpPassword = ftpPassword;
}
public List<UINotificationEmail> getEmails()
{
if ( this.emails == null )
{
this.emails = new ArrayList<UINotificationEmail>();
}
return emails;
}
public void setEmails(List<UINotificationEmail> emails)
{
this.emails = emails;
}
}
更新 2这是杰克逊的输出.:
{
"vendorName":"MAIL",
"vendorId":45,
"emails":
[
{
"emailAddress":"dfg",
"success":false,
"failure":false,
"flags":0
}
],
"vendorType":"DFG",
"ftpFlag":true,
"ftpHost":"kdsfjng",
"ftpPath":"dsfg",
"ftpUser":"sdfg",
"ftpPassword":"sdfg",
"status":"A"
}
这是我在 POST 中返回的对象的结构:
And here is the structure of the object I'm returning on the POST:
{
"vendorId":"45",
"vendorName":"MAIL",
"vendorType":"DFG",
"ftpFlag":true,
"ftpHost":"kdsfjng",
"ftpUser":"sdfg",
"ftpPath":"dsfg",
"ftpPassword":"sdfg",
"status":"A",
"emails":
[
{
"success":"false",
"failure":"false",
"emailAddress":"dfg"
},
{
"success":"true",
"failure":"true",
"emailAddress":"pfc@sj.org"
}
]
}
我也尝试使用来自 www.json.org 的 JSON 库进行序列化，结果正是您在上面看到的.但是，当我发布该数据时，传递给控制器的 UIVendor 对象中的所有字段都为 null(尽管该对象不是).
I've tried serializing using the JSON library from www.json.org as well, and the result is exactly what you see above. However, when I post that data, all of the fields in the UIVendor object passed to the controller are null (although the object is not).
推荐答案
更新: 从 Spring 3.1 开始，可以使用 @Valid On @RequestBody 控制器方法参数.
Update: since Spring 3.1, it's possible to use @Valid On @RequestBody Controller Method Arguments.
@RequestMapping(value="/ajax/saveVendor.do", method = RequestMethod.POST)
public @ResponseBody AjaxResponse saveVendor( @Valid @RequestBody UIVendor vendor,
BindingResult result,
Locale currentLocale )
<小时>
经过多次反复试验，我终于尽可能地弄清楚了问题所在.使用以下控制器方法签名时:
After much trial and error, I've finally figured out, as well as I can, what the problem is. When using the following controller method signature:
@RequestMapping(value="/ajax/saveVendor.do", method = RequestMethod.POST)
public @ResponseBody AjaxResponse saveVendor( @Valid UIVendor vendor,
BindingResult result,
Locale currentLocale )
客户端脚本必须以后期数据(通常是application/x-www-form-urlencoded")格式(即field=value&field2=value2)传递对象中的字段.这是在 jQuery 中完成的，如下所示:
The client script has to pass the field in the object in post-data (typically "application/x-www-form-urlencoded") format (i.e., field=value&field2=value2). This is done in jQuery like this:
$.post( "mycontroller.do", $.param(object), callback, "json" )
这适用于没有子对象或集合的简单 POJO 对象，但是一旦您向传递的对象引入了显着的复杂性，Spring 的映射逻辑就无法识别 jQuery 用于序列化对象数据的符号:
This works fine for simple POJO objects that don't have child objects or collections, but once you introduce significant complexity to the object being passed, the notation used by jQuery to serialize the object data is not recognized by Spring's mapping logic:
object[0][field]
我解决这个问题的方法是将控制器中的方法签名改为:
The way that I solved this problem was to change the method signature in the controller to:
@RequestMapping(value="/ajax/saveVendor.do", method = RequestMethod.POST)
public @ResponseBody AjaxResponse saveVendor( @RequestBody UIVendor vendor,
Locale currentLocale )
并将客户端的调用更改为:
And change the call from client to:
$.ajax(
{
url:"ajax/mycontroller.do",
type: "POST",
data: JSON.stringify( objecdt ),
success: callback,
dataType: "json",
contentType: "application/json"
} );
这需要使用 JSON javascript 库.它还强制 contentType 为application/json"，这是 Spring 在使用 @RequestBody 注解时所期望的，并将对象序列化为 Jackson 可以反序列化为有效对象结构的格式.
This requires the use of the JSON javascript library. It also forces the contentType to "application/json", which is what Spring expects when using the @RequestBody annotation, and serializes the object to a format that Jackson can deserialize into a valid object structure.
唯一的副作用是现在我必须在控制器方法内部处理我自己的对象验证，但这相对简单:
The only side effect is that now I have to handle my own object validation inside of the controller method, but that's relatively simple:
BindingResult result = new BeanPropertyBindingResult( object, "MyObject" );
Validator validator = new MyObjectValidator();
validator.validate( object, result );
如果有人对改进此过程有任何建议，我会全力倾听.
If anyone has any suggestions to improve upon this process, I'm all ears.
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