java - Spring Boot 以自己的对象作为键返回 Map 的问题

Question

我对 Spring Boot 有疑问。我正在制作一个 REST 应用程序，并且我有一个返回 Map(Share, Integer) 的服务

Share是我写的一个类:

public class Share {

    private String ticker;
    private String name;
    private Double value;

    public Share() {
        super();
    }

    public Share(String ticker, String name, Double value) {
        super();
        this.ticker = ticker;
        this.name = name;
        this.value = value;
    }

    public String getTicker() {
        return ticker;
    }

    public void setTicker(String ticker) {
        this.ticker = ticker;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Double getValue() {
        return value;
    }

    public void setValue(Double value) {
        this.value = value;
    }

    @Override
    public int hashCode() {
       final int prime = 31;
       int result = 1;
        result = prime * result + ((ticker == null) ? 0 : ticker.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Share other = (Share) obj;
        if (ticker == null) {
            if (other.ticker != null)
                return false;
            } else if (!ticker.equals(other.ticker))
                return false;
        return true;
    } 

    @Override
    public String toString() {
        return "Share [ticker=" + ticker + ", name=" + name + ", value=" + value + "]";
    }
}

@RestController 是:

public class ShareController {

    @Autowired
    private ShareBussines shareBussines;

    @RequestMapping("/getShare/{ticker}")
    public Share getShare(@PathVariable("ticker") String ticker) throws BrokerNotFoundException, BrokerArgumentException, BrokerGeneralException {
        return shareBussines.getShare(ticker);
    }

    @RequestMapping(value="/buyShares", method=RequestMethod.POST)
    public Map<Share, Integer> buyShares(@RequestBody Map<String,Double> sharesToBuy) throws BrokerGeneralException, BrokerArgumentException, BrokerInsufficientStockException {
        return shareBussines.buyShares(sharesToBuy);
    }

}

问题出在我从 Postman 调用服务时。

结果是:

{
    "Share [ticker=AMZN, name=Amazon, value=259.32126508258295]": 1,
    "Share [ticker=GOOGL, name=Google, value=249.35339337497606]": 1,
    "Share [ticker=FB, name=Facebook, value=181.15005639608364]": 55
}

map 键是 share.toString()...我希望键是共享 JSON。我尝试从 Share 类中删除 toString 方法，但结果是:

{
    "Share@1eb87f": 1,
    "Share@40d9fab": 1,
    "Share@8db": 54
}

它正在使用对象的 toString()。

感谢您的建议。

Answer 1

首先，它会像您编写代码一样工作:

@RequestMapping(value="/buyShares", method=RequestMethod.POST)
public Map<Share, Integer> buyShares(@RequestBody Map<String,Double> sharesToBuy) throws BrokerGeneralException, BrokerArgumentException, BrokerInsufficientStockException {
    return shareBussines.buyShares(sharesToBuy);
}

分享是这里的关键。这有点奇怪。为什么不创建一些像这样的对象:

public class ShareResponse {
    private Share share;
    private Integer someVal; // that's the one you have in your Map as a value

    // getters and setters
}

然后稍微改变你的服务:

@RequestMapping(value="/buyShares", method=RequestMethod.POST)
public List<ShareResponse>  buyShares(@RequestBody Map<String,Double> sharesToBuy) throws BrokerGeneralException, BrokerArgumentException, BrokerInsufficientStockException {
    // do your business here, create a list of ShareResponse and return it
    return shareBussines.buyShares(sharesToBuy); // instead of this
}

你应该得到一个有效的、“格式化”的 JSON。如果您需要每个项目都可以通过某个唯一值进行识别，只需将一些 ID 字段添加到 ShareResponse。

这有什么意义吗？)