Detailed code examples and comment analysis of C# read and write JSON files

1. Preparation

Processing JSON files in C# is usually done by third-party libraries, such as(also known as). It provides rich APIs for serialization and deserialization of JSON. If you are using newer .NET Core or .NET 6 and later, you can also choose to use the built-in onelibrary. Here we will take it as an example because it is widely used in the .NET ecosystem and has mature functions.

First, make sure you have installed the library in your project through the NuGet package manager. If you have not installed it, open Tools -> NuGet Package Manager -> NuGet Packages for Manage Solutions in Visual Studio, search and install ".

2. Read JSON files

Step 1: Introduce the necessary namespace

Csharp

using System;
using ;
using ;

Step 2: Write code to read JSON files

Suppose we have a name calledThe file containing a JSON object representing user information:

Json

{
  "Name": "John Doe",
  "Age": 30,
  "IsAdmin": false,
  "Skills": ["C#", "JavaScript", "SQL"]
}

We can read and deserialize it into a C# object using the following code:

Csharp

// Define a C# kindpublic class User corresponding to the JSON structure{
    public string Name { get; set; }
    public int Age { get; set; }
    public bool IsAdmin { get; set; }
    public string[] Skills { get; set; }
}

public static User ReadJsonFile()
{
    // JSON file path    string filePath = @"path\to\";

    try
    {
        // Open and read the file content        using (StreamReader fileReader = new StreamReader(filePath))
        {
            // Get JSON string from file            string jsonContent = ();

            // Use deserialization of JSON string as User object            User user = <User>(jsonContent);

            return user;
        }
    }
    catch (FileNotFoundException ex)
    {
        ($"Error: document {filePath} not found。");
        throw;
    }
    catch (Exception ex)
    {
        ($"Error: Read or parseJSONdocument时发生错误。{}");
        throw;
    }
}

Code comment description

• UserThe class defines properties that match the JSON structure so that JSON data is mapped to the corresponding C# object when deserialized.
• ReadJsonFileMethod:
  • First specify the path to the JSON file.
  • useStreamReaderOpen and read the file contents into a string variablejsonContentmiddle.
  • Call<User>Method, convert JSON string toUserAn instance of type.
  • usetry-catchStatements catch possible exceptions, such as files not found or errors that occur during parsing, and handle them appropriately.

3. Write to JSON file

Step 1: Make sure that the required namespace has been introduced (same as the read section)

Csharp

using System;
using ;
using ;

Step 2: Write code to write JSON file

Suppose we have oneUserobject, want to serialize it into a JSON string and save it to a nameIn the file:

Csharp

public static void WriteJsonFile(User user)
{
    // JSON file output path    string outputPath = @"path\to\";

    try
    {
        // Serialize the User object into a JSON string        string jsonOutput = (user, );

        // Write JSON string to file        using (StreamWriter fileWriter = new StreamWriter(outputPath))
        {
            (jsonOutput);
        }

        ("User data successfully written to JSON file.");
    }
    catch (Exception ex)
    {
        ($"Error: WriteJSONAn error occurred while file。{}");
        throw;
    }
}

Code comment description

• WriteJsonFileMethod to accept oneUserObject as parameter.
• useThe method will be passed inUserSerialize objects into formatted JSON strings (parameters make it readable).
• Create aStreamWriterobject, specifiedoutputPathOpen the file and write the JSON string to the file.
• Use the sametry-catchStatements catch and handle possible exceptions.

Summarize

The above code shows how to use C# to read and write JSON files. By defining a C# class that matches the JSON structure, you can easily convert JSON data to the object model in your application. In practical applications, you can just replace or extend the classes and methods in these examples to adapt to your specific business needs. Be sure to pay attention to the correctness of file paths and permissions for file operations, as well as to adopt appropriate recovery or notification mechanisms when handling exceptions.

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