使用 thymeleaf 并使用 java Spring 从 java 对象中获取字符串

Deiutz 发表于 Dev

戴伊茨

我尝试从带有 thymeleaf 并使用 java Spring 作为框架的 java 对象获取字符串，但出现错误，错误是：

org.springframework.expression.spel.SpelEvaluationException：EL1004E：方法调用：在 java.lang.String 类型上找不到方法 getSrc()

html代码是：

<div th:each="product: ${products}">
    <div class="col-1">
        <div class="gallery">
            <div th:each="imgg :${product.id}+img">
                <p th:text="${imgg.getSrc()}"></p>
            </div>
            <div class="desc">
                <p th:text="${product.name}"></p>
            </div>
        </div>
    </div>
</div>

控制器是：

@GetMapping("/")
public String dashboard(ModelMap model) {
  List < CpuProduct > CpuProducts = cpurepo.findAll();

  model.put("products", CpuProducts);

  CpuProducts.forEach(prod ->{

    model.put(prod.getId() + "img", prod.getPhotos());
  });

  return "index";
}

CpuProduct 类是：

    package com.deiutz.BuildIT.User.products;

import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.OrderColumn;

@Entity
public class CpuProduct {

    private long id;
    private double price;
    private String description;
    private String model;
    private String name;
    private Set<Image> photos;
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    public long getId() {
        // TODO Auto-generated method stub
        return id;
    }

    public void setId(long id) {
        this.id = id;

    }

    public double getPrice() {
        // TODO Auto-generated method stub
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }


    public String getDescrpiton() {

        return description;
    }


    public void setDescrpiton(String description) {
        this.description = description;

    }


    public String getModel() {

        return model;
    }


    public void setModel(String model) {
        this.model = model;

    }


    public String getName() {

        return name;
    }


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

    }

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER, mappedBy = "product")
    @OrderColumn
    public Set<Image> getPhotos() {
        return this.photos;
    }


    public void setPhotos(Set<Image> photos) {
        this.photos = photos;

    }


}

图像类是：

    package com.deiutz.BuildIT.User.products;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.ManyToOne;

@Entity

public class Image {

    private long id;
    private byte[] foto;
    private CpuProduct product;
    private String src = "img/" + id;


    public byte[] getFoto() {
        return foto;
    }

    public void setFoto(byte[] foto) {
        this.foto = foto;
    }

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    public long getId() {
        return id;
    }


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

    @ManyToOne()
    public CpuProduct getProduct() {
        return product;
    }

    public void setProduct(CpuProduct product) {
        this.product = product;
    }

    public String getSrc() {
        return src;
    }

    public void setSrc(String src) {
        this.src = src;
    }

}

开发进度

我不确定是什么导致了你的问题。可能您无法通过在模板中添加两个字符串来访问模型映射中的变量，它只会将其连接为字符串。

另一方面，我可以为您提供一个解决方案（一个更干净的解决方案）。简而言之，让我们在一个模型中放入一张按产品 id 映射的照片地图，而不是按包含照片的产品 id 放置“n”个模型。

model.put("products", cpuProducts);

Map<Integer, List<Photo>> photosByProduct = cpuProducts.stream()
            .collect(Collectors.toMap(CpuProduct::getId, CpuProduct::getPhotos));

//          Or using forEach
//
//          Map<Integer, List<Photo>> photosByProduct = new HashMap<>();
//          cpuProducts.forEach(cpuProduct -> {
//              photosByProduct.put(cpuProduct.getId(), cpuProduct.getPhotos())
//          });

model.put("photos", photosByProduct);

<div th:each="product: ${products}">
    <div class="col-1">
        <div class="gallery">
            <div th:each="photo: ${photos.get(product.id)}">
                <p th:text="${photo.src}"></p>
            </div>
            <div class="desc">
                <p th:text="${product.name}"></p>
            </div>
        </div>
    </div>
</div>

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