dynamodb java sdk collection type support,reference doc https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/DynamoDBMapper.DataTypes.html

Order.java

package com.example.aws.dynamodb;

import java.math.BigDecimal;
import java.time.Instant;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import lombok.ToString;
import lombok.experimental.Accessors;
import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbBean;
import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbPartitionKey;
import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbSecondaryPartitionKey;
import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbSecondarySortKey;

@DynamoDbBean
@Accessors(chain = true)
@ToString
public class Order {

    private Long id;

    private Long cusId;

    private Long orderTime;

    private BigDecimal orderAmt;

    private Instant shipTime;

    private OrderStatus orderStatus;

    //Set not support custom java object,i.e OrderItem
    private Set<String> orderItemSet = new HashSet<>();

    private List<OrderItem> itemList = new ArrayList<>();

    private List<Map<String, OrderItem>> mapList = new ArrayList<>();

    @DynamoDbPartitionKey
    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    @DynamoDbSecondaryPartitionKey(indexNames = "cusid_ordertime")
    public Long getCusId() {
        return cusId;
    }

    public void setCusId(Long cusId) {
        this.cusId = cusId;
    }

    @DynamoDbSecondarySortKey(indexNames = "cusid_ordertime")
    public Long getOrderTime() {
        return orderTime;
    }

    public void setOrderTime(Long orderTime) {
        this.orderTime = orderTime;
    }

    public BigDecimal getOrderAmt() {
        return orderAmt;
    }

    public void setOrderAmt(BigDecimal orderAmt) {
        this.orderAmt = orderAmt;
    }

    public Instant getShipTime() {
        return shipTime;
    }

    public void setShipTime(Instant shipTime) {
        this.shipTime = shipTime;
    }

    public Set<String> getOrderItemSet() {
        return orderItemSet;
    }

    public void setOrderItemSet(Set<String> orderItemSet) {
        this.orderItemSet = orderItemSet;
    }

    public OrderStatus getOrderStatus() {
        return orderStatus;
    }

    public void setOrderStatus(OrderStatus orderStatus) {
        this.orderStatus = orderStatus;
    }

    public List<OrderItem> getItemList() {
        return itemList;
    }

    public void setItemList(List<OrderItem> itemList) {
        this.itemList = itemList;
    }

    public List<Map<String, OrderItem>> getMapList() {
        return mapList;
    }

    public void setMapList(List<Map<String, OrderItem>> mapList) {
        this.mapList = mapList;
    }
}

OrderItem.java

package com.example.aws.dynamodb;

import java.math.BigDecimal;

import lombok.ToString;
import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbBean;

@DynamoDbBean
@ToString
public class OrderItem {
    private int qit;

    private BigDecimal amt;


    public int getQit() {
        return qit;
    }

    public void setQit(int qit) {
        this.qit = qit;
    }

    public BigDecimal getAmt() {
        return amt;
    }

    public void setAmt(BigDecimal amt) {
        this.amt = amt;
    }

}