Introduction to JSON usage scenarios and precautions

JSON The use of scenarios and precautions

JSON Of 2 A structural form

Key value pair form

• {
        
    "person": {
        
      "name": "pig",
      "age": "18",
      "sex": "man",
      "hometown": {
        
        "province": " Jiangxi Province ",
        "city": " Fuzhou City ",
        "county": " Chongren county "
      }
    }
  }
  

• structural JSON The data rule is ： A disordered “‘ name / value ’ Yes ” aggregate . An object to { Left parenthesis Start , } Right bracket end . Every “ name ” Followed by a : The colon ;“‘ name / value ’ Yes ” Used between , comma Separate

Array form

• ["pig", 18, "man", " Chongren County, Fuzhou City, Jiangxi Province "]
  

• In array form JSON Data is value （value） Ordered set of . An array to [ Left bracket Start , ] Right bracket end . Use between values , comma Separate

JOSN Of 6 Type of data

• string： character string , It must be enclosed in double quotation marks
• number： The number , And JavaScript Of number Agreement , Integers （ Don't use decimal or exponential counting ） At most 15 position . The maximum number of decimal places is 17
• object：JavaScript The object form of ,{ key:value } Representation , Can be nested
• array： Array ,JavaScript Of Array Representation [ value ], Can be nested
• true/false： Boolean type ,JavaScript Of boolean type
• null： Null value ,JavaScript Of null

JSON Use scenarios

Interface returns data

JSON The most used place is Web 了 , Today's data interfaces are basically returned JSON, Specific and detailed scenes include

• Ajxa Asynchronous access to data
• RPC The remote invocation
• Separate the data returned by the back end and the front end
• to open up API, Such as Baidu 、 Some open interfaces, like Gaud
• Cooperation interface between enterprises

serialize

• All variables are stored in memory when the program is running , In case of program restart or machine downtime , Then the data is lost . Some data in memory needs to be saved for the next program or other programs

• Save the data in memory or in the database , Or save directly to a file , and The process of transforming data in memory into data that can be saved or transferred is called serialization

• The normal serialization is to program the The object is directly converted to something that can be saved or transferred , This saves the type information of the object , and JSON Serialization does not preserve the object type

Generate Token

• Token The way to do login authentication , And then through Token selection Redis Cached user information in , After that JWT Appearance , The verification method is more simple and convenient , There is no need to pass Redis cache , It's directly based on Token Take out the saved user information , And right Token Availability check , Single sign on is easier

The configuration file

• JSON It's not the right configuration file , Because it can't write notes 、 As the readability of the configuration file is poor and so on