What's the difference between “URIEncoding” of

There may be many ways to solve encoding problem:

Encoding filter like Spring MVC UTF-8 Encoding
Setting URIEncoding=UTF-8 in server.xml of Tomcat , like http://struts.apache.org/release/2.1.x/docs/how-to-support-utf-8-uriencoding-with-tomcat.html.
request.setCharacterEncoding( utf-8 )

Today, I have a problem that path param is not decoded well like

@ResponseBody
@RequestMapping(value="/context/method/{key}",method=RequestMethod.GET,produces = "application/json;charset=utf-8")
public String method(@PathVariable String key){

    logger.info("key="+key+"------------");
}

I can see that the key is decoded bad! If I pass a word "新浪" from the front end, it will become "æ°æµª". I write the below code to examine if the server is decoding this with "ISO-8859-1":

public static void main(String args[]) throws UnsupportedEncodingException{
    String key="新浪";
    byte[] bytes=key.getBytes("UTF-8");
    String decode=new String(bytes,"ISO-8859-1");
    System.out.println(decode);
}

And it comes out with the same output "æ°æµª". so indeed, the path variable is decoded with ISO-8859-1.

And then I try to add a filter to my web.xml to solve this problem:

  <filter>
    <filter-name>encodingFilter</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>
    <init-param>
        <param-name>forceEncoding</param-name>
        <param-value>true</param-value>
    </init-param>
 </filter>

  <filter-mapping>
    <filter-name>encodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
 </filter-mapping>

But the same garbled.

Until I set below to my server.xml

<Connector connectionTimeout="20000" port="8080" protocol="HTTP/1.1" redirectPort="8443"
           URIEncoding="UTF-8" useBodyEncodingForURI="true"   ----Here is Added
/>

And it works for this even I remove the filter.

But I am still very confusing about the encoding issue. And besides , this is only GET method, if it is POST method, I guess the solution will probably be different

Can anybody please explain that what difference encoding solution should we take for what kind of problem ?

Thank you!

CharacterEncodingFilter configures encoding of request body. That is, it affects encoding of POST request parameters, etc, but doesn't affect encoding of GET parameters
URIEncoding is used to specify encoding of the URI, therefore it affects GET parameters
useBodyEncodingForURI="true" tells Tomcat to use encoding configured for request body when decoding URIs. So, as far as I understand, if you set CharacterEncodingFilter and useBodyEncodingForURI="true" then you don't need URIEncoding.