How to Solve Ajax Error 500 (Internal Server Error)

==========error======={"readyState":4,"responseText":"<html><head><title>Apache Tomcat/6.0.35 - Error report</title><style><!--H1 {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:22px;} H2 {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:16px;} H3 {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:14px;} BODY {font-family:Tahoma,Arial,sans-serif;color:black;background-color:white;} B {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;} P {font-family:Tahoma,Arial,sans-serif;background:white;color:black;font-size:12px;}A {color : black;}A.name {color : black;}HR {color : #525D76;}--></style> </head><body><h1>HTTP Status 500 - </h1><HR size=\"1\" noshade=\"noshade\"><p><b>type</b> Exception report</p><p><b>message</b> <u></u></p><p><b>description</b> <u>The server encountered an internal error () that prevented it from fulfilling this request.</u></p><p><b>exception</b> <pre>org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: Object is null (through reference chain: java.util.HashMap[&quot;data&quot;]-&>java.util.ArrayList[0]-&>net.sf.json.JSONObject[&quot;applyExcuse&quot;]-&>net.sf.json.JSONNull[&quot;empty&quot;]); nested exception is org.codehaus.jackson.map.JsonMappingException: Object is null (through reference chain: java.util.HashMap[&quot;data&quot;]-&>java.util.ArrayList[0]-&>net.sf.json.JSONObject[&quot;applyExcuse&quot;]-&>net.sf.json.JSONNull[&quot;empty&quot;])\n\torg.springframework.http.converter.json.MappingJacksonHttpMessageConverter.writeInternal(MappingJacksonHttpMessageConverter.java:194)\n\torg.springframework.http.converter.AbstractHttpMessageConverter.write(AbstractHttpMessageConverter.java:179)\n\torg.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:148)\n\torg.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(……

Various explanations on the Internet, but not eggs

Error reported in “codeexception.Org” in “codeexception.Org”  ”   This means that there is null in the map value

 

Null values cannot be converted to JSON when the front end is returned

Ajax defines data transfer as JSON

Solution:

1. Loop by yourself or find a tool class to handle null ”

2. Returns the front-end string. The front end is converted to JSON.

Similar Posts: