When submitting data to the background through ajax on the jsp page, a 400 error was reported. After consulting the information, the cause and solution were found as follows:
HTTP error 400
400 Request error
Because the syntax format is incorrect, the server cannot understand this request. Without modification, the client program cannot repeat this request.
Reasons:
1. The field name or field type
of the data submitted by the front end is inconsistent with the entity class of the back end , which cannot be encapsulated; 2. The data submitted by the front end to the back end should be of json string type, and the front end does not convert the object into a string Types of;
Solution:
1) Compare the field names and types to ensure consistency;
2) Use stringify to convert the object passed by the front end into a string, data: JSON.stringify (param).
Note: Finally, it is found that the time in the data is an incorrect type. The time type is the Date type, and it should be in the java.sql.Date package, not in the java.util.Date.
