设计一个基于hyperledger fabric区块链技术的农产品质量溯源系统，数据分为三处储存，生产经营者线下MySQL数据库储存，线上云储存加密备份，区块链对比储存数据信息的哈希值，用以校对数据的真实性。 设计该系统各主要模块的代码

以下是基于Hyperledger Fabric的农产品质量溯源系统的主要模块和代码设计：

1. 定义参与者和商品信息的结构体

type Participant struct {
    ID          string `json:"id"`
    Name        string `json:"name"`
    Type        string `json:"type"`
    Address     string `json:"address"`
}

type Product struct {
    ID          string `json:"id"`
    Name        string `json:"name"`
    Grade       string `json:"grade"`
    Origin      string `json:"origin"`
    Production  string `json:"production"`
    Participants []Participant `json:"participants"`
}

2. 定义智能合约

type SmartContract struct {
}

func (s *SmartContract) Init(ctx contractapi.TransactionContextInterface) error {
    return nil
}

func (s *SmartContract) CreateProduct(ctx contractapi.TransactionContextInterface, productID string, productName string, productGrade string, productOrigin string, productProduction string) error {
    productKey, err := ctx.GetStub().CreateCompositeKey("product", []string{productID})
    if err != nil {
        return fmt.Errorf("failed to create composite key: %v", err)
    }

    // Check if product already exists
    productAsBytes, err := ctx.GetStub().GetState(productKey)
    if err != nil {
        return fmt.Errorf("failed to read from world state: %v", err)
    }
    if productAsBytes != nil {
        return fmt.Errorf("the product %s already exists", productID)
    }

    // Create a new product
    product := &Product{
        ID:         productID,
        Name:       productName,
        Grade:      productGrade,
        Origin:     productOrigin,
        Production: productProduction,
        Participants: []Participant{},
    }

    // Add product to world state
    productAsBytes, err = json.Marshal(product)
    if err != nil {
        return err
    }
    err = ctx.GetStub().PutState(productKey, productAsBytes)
    if err != nil {
        return fmt.Errorf("failed to write to world state: %v", err)
    }

    return nil
}

func (s *SmartContract) AddParticipant(ctx contractapi.TransactionContextInterface, productID string, participantID string, participantName string, participantType string, participantAddress string) error {
    productKey, err := ctx.GetStub().CreateCompositeKey("product", []string{productID})
    if err != nil {
        return fmt.Errorf("failed to create composite key: %v", err)
    }

    // Check if product exists
    productAsBytes, err := ctx.GetStub().GetState(productKey)
    if err != nil {
        return fmt.Errorf("failed to read from world state: %v", err)
    }
    if productAsBytes == nil {
        return fmt.Errorf("the product %s does not exist", productID)
    }

    // Add new participant to the product
    var product Product
    err = json.Unmarshal(productAsBytes, &product)
    if err != nil {
        return fmt.Errorf("failed to unmarshal product: %v", err)
    }
    participant := Participant{
        ID:         participantID,
        Name:       participantName,
        Type:       participantType,
        Address:    participantAddress,
    }
    product.Participants = append(product.Participants, participant)

    // Update product in world state
    productAsBytes, err = json.Marshal(product)
    if err != nil {
        return err
    }
    err = ctx.GetStub().PutState(productKey, productAsBytes)
    if err != nil {
        return fmt.Errorf("failed to write to world state: %v", err)
    }

    return nil
}

func (s *SmartContract) QueryProduct(ctx contractapi.TransactionContextInterface, productID string) (*Product, error) {
    productKey, err := ctx.GetStub().CreateCompositeKey("product", []string{productID})
    if err != nil {
        return nil, fmt.Errorf("failed to create composite key: %v", err)
    }

    // Get product from world state
    productAsBytes, err := ctx.GetStub().GetState(productKey)
    if err != nil {
        return nil, fmt.Errorf("failed to read from world state: %v", err)
    }
    if productAsBytes == nil {
        return nil, fmt.Errorf("the product %s does not exist", productID)
    }

    // Return product
    var product Product
    err = json.Unmarshal(productAsBytes, &product)
    if err != nil {
        return nil, fmt.Errorf("failed to unmarshal product: %v", err)
    }
    return &product, nil
}

3. 集成MySQL数据库

type MySQLHandler struct {
    Connection string
    Username   string
    Password   string
    DBName     string
}

func (h *MySQLHandler) AddParticipant(productID string, participantID string, participantName string, participantType string, participantAddress string) error {
    db, err := sql.Open("mysql", fmt.Sprintf("%s:%s@tcp(%s)/%s", h.Username, h.Password, h.Connection, h.DBName))
    if err != nil {
        return err
    }
    defer db.Close()

    stmt, err := db.Prepare("INSERT INTO Participants (productID, participantID, participantName, participantType, participantAddress) VALUES (?, ?, ?, ?, ?)")
    if err != nil {
        return err
    }
    defer stmt.Close()

    _, err = stmt.Exec(productID, participantID, participantName, participantType, participantAddress)
    if err != nil {
        return err
    }

    return nil
}

func (h *MySQLHandler) GetParticipants(productID string) ([]Participant, error) {
    participants := []Participant{}

    db, err := sql.Open("mysql", fmt.Sprintf("%s:%s@tcp(%s)/%s", h.Username, h.Password, h.Connection, h.DBName))
    if err != nil {
        return participants, err
    }
    defer db.Close()

    rows, err := db.Query("SELECT participantID, participantName, participantType, participantAddress FROM Participants WHERE productID = ?", productID)
    if err != nil {
        return participants, err
    }
    defer rows.Close()

    for rows.Next() {
        var participant Participant
        err = rows.Scan(&participant.ID, &participant.Name, &participant.Type, &participant.Address)
        if err != nil {
            return participants, err
        }
        participants = append(participants, participant)
    }

    return participants, nil
}

4. 集成云储存

type S3Handler struct {
    Region string
    Bucket string
    Prefix string
    Client *s3.S3
}

func (h *S3Handler) UploadFile(file []byte, filename string) error {
    key := fmt.Sprintf("%s/%s", h.Prefix, filename)

    _, err := h.Client.PutObject(&s3.PutObjectInput{
        Body:   bytes.NewReader(file),
        Bucket: aws.String(h.Bucket),
        Key:    aws.String(key),
    })
    if err != nil {
        return err
    }

    return nil
}

func (h *S3Handler) DownloadFile(filename string) ([]byte, error) {
    key := fmt.Sprintf("%s/%s", h.Prefix, filename)

    result, err := h.Client.GetObject(&s3.GetObjectInput{
        Bucket: aws.String(h.Bucket),
        Key:    aws.String(key),
    })
    if err != nil {
        return nil, err
    }
    defer result.Body.Close()

    data, err := ioutil.ReadAll(result.Body)
    if err != nil {
        return nil, err
    }

    return data, nil
}

5. 实现哈希值对比

func (s *SmartContract) VerifyHash(ctx contractapi.TransactionContextInterface, productID string, data []byte) (bool, error) {
    productKey, err := ctx.GetStub().CreateCompositeKey("product", []string{productID})
    if err != nil {
        return false, fmt.Errorf("failed to create composite key: %v", err)
    }

    // Get product from world state
    productAsBytes, err := ctx.GetStub().GetState(productKey)
    if err != nil {
        return false, fmt.Errorf("failed to read from world state: %v", err)
    }
    if productAsBytes == nil {
        return false, fmt.Errorf("the product %s does not exist", productID)
    }

    // Calculate hash value
    hash := sha256.Sum256(data)

    // Get hash value from world state
    hashKey, err := ctx.GetStub().CreateCompositeKey("hash", []string{productID})
    if err != nil {
        return false, fmt.Errorf("failed to create composite key: %v", err)
    }
    hashValueAsBytes, err := ctx.GetStub().GetState(hashKey)
    if err != nil {
        return false, fmt.Errorf("failed to read from world state: %v", err)
    }

    // Compare hash values
    if hashValueAsBytes == nil {
        return false, fmt.Errorf("the hash value for product %s does not exist", productID)
    }
    hashValue := sha256.Sum256(hashValueAsBytes)
    if !bytes.Equal(hash[:], hashValue[:]) {
        return false, nil
    }

    return true, nil
}

以上是基于Hyperledger Fabric的农产品质量溯源系统的主要模块和代码设计，希望对您有所帮助。