如何从getItem dynamoDB (JavaScript)中检索特定对象？

var AWS = require("aws-sdk");
AWS.config.update({
  region: "us-west-2", // 设置区域
  endpoint: "http://localhost:8000" // 设置DynamoDB的端点
});
var docClient = new AWS.DynamoDB.DocumentClient();

var params = {
  TableName: "your_table_name",
  Key: {
    "primary_key_name": primary_key_value
  }
};

docClient.get(params, function(err, data) {
  if (err) {
    console.error("Unable to read item. Error JSON:", JSON.stringify(err, null, 2));
  } else {
    console.log("GetItem succeeded:", JSON.stringify(data, null, 2));
  }
});