Mysql 多通、单通和联接表

我有一个例子，当它工作时，我只想修改它，但我做不到。 以下是示例的链接： 无论如何，我将其发布到：

以下是实体的图片：

下面是java类： Stock.java

package com.mkyong.stock;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import static javax.persistence.GenerationType.IDENTITY;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import javax.persistence.UniqueConstraint;

@Entity
@Table(name = "stock", catalog = "mkyongdb", uniqueConstraints = {
        @UniqueConstraint(columnNames = "STOCK_NAME"),
        @UniqueConstraint(columnNames = "STOCK_CODE") })
public class Stock implements java.io.Serializable {

    private Integer stockId;
    private String stockCode;
    private String stockName;
    private Set<StockCategory> stockCategories = new HashSet<StockCategory>(0);

    public Stock() {
    }

    public Stock(String stockCode, String stockName) {
        this.stockCode = stockCode;
        this.stockName = stockName;
    }

    public Stock(String stockCode, String stockName,
            Set<StockCategory> stockCategories) {
        this.stockCode = stockCode;
        this.stockName = stockName;
        this.stockCategories = stockCategories;
    }

    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "STOCK_ID", unique = true, nullable = false)
    public Integer getStockId() {
        return this.stockId;
    }

    public void setStockId(Integer stockId) {
        this.stockId = stockId;
    }

    @Column(name = "STOCK_CODE", unique = true, nullable = false, length = 10)
    public String getStockCode() {
        return this.stockCode;
    }

    public void setStockCode(String stockCode) {
        this.stockCode = stockCode;
    }

    @Column(name = "STOCK_NAME", unique = true, nullable = false, length = 20)
    public String getStockName() {
        return this.stockName;
    }

    public void setStockName(String stockName) {
        this.stockName = stockName;
    }

    @OneToMany(fetch = FetchType.LAZY, mappedBy = "pk.stock", cascade=CascadeType.ALL)
    public Set<StockCategory> getStockCategories() {
        return this.stockCategories;
    }

    public void setStockCategories(Set<StockCategory> stockCategories) {
        this.stockCategories = stockCategories;
    }

}

Stockcategoryid.java

package com.mkyong.stock;

import javax.persistence.Embeddable;
import javax.persistence.ManyToOne;

@Embeddable
public class StockCategoryId implements java.io.Serializable {

    private Stock stock;
    private Category category;

    @ManyToOne
    public Stock getStock() {
        return stock;
    }

    public void setStock(Stock stock) {
        this.stock = stock;
    }

    @ManyToOne
    public Category getCategory() {
        return category;
    }

    public void setCategory(Category category) {
        this.category = category;
    }

    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        StockCategoryId that = (StockCategoryId) o;

        if (stock != null ? !stock.equals(that.stock) : that.stock != null) return false;
        if (category != null ? !category.equals(that.category) : that.category != null)
            return false;

        return true;
    }

    public int hashCode() {
        int result;
        result = (stock != null ? stock.hashCode() : 0);
        result = 31 * result + (category != null ? category.hashCode() : 0);
        return result;
    }

}

Category.java

package com.mkyong.stock;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import static javax.persistence.GenerationType.IDENTITY;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;

@Entity
@Table(name = "category", catalog = "mkyongdb")
public class Category implements java.io.Serializable {

    private Integer categoryId;
    private String name;
    private String desc;
    private Set<StockCategory> stockCategories = new HashSet<StockCategory>(0);

    public Category() {
    }

    public Category(String name, String desc) {
        this.name = name;
        this.desc = desc;
    }

    public Category(String name, String desc, Set<StockCategory> stockCategories) {
        this.name = name;
        this.desc = desc;
        this.stockCategories = stockCategories;
    }

    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "CATEGORY_ID", unique = true, nullable = false)
    public Integer getCategoryId() {
        return this.categoryId;
    }

    public void setCategoryId(Integer categoryId) {
        this.categoryId = categoryId;
    }

    @Column(name = "NAME", nullable = false, length = 10)
    public String getName() {
        return this.name;
    }

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

    @Column(name = "[DESC]", nullable = false)
    public String getDesc() {
        return this.desc;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }

    @OneToMany(fetch = FetchType.LAZY, mappedBy = "pk.category")
    public Set<StockCategory> getStockCategories() {
        return this.stockCategories;
    }

    public void setStockCategories(Set<StockCategory> stockCategories) {
        this.stockCategories = stockCategories;
    }

}

---

但是我想不出来。

试试下面这样的方法

@ManyToOne @JoinColumns({ @JoinColumn(name = "STOCK_ID", referencedColumnName = "STOCK_ID"), 
@JoinColumn(name = "CATEGORY_ID", referencedColumnName = "CATEGORY_ID") }) 
private StockCategory stockCategory;

---

您遇到了什么异常？原因：org.hibernate.AnnotationException:外键引用的列数错误

package com.mkyong.stock;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import static javax.persistence.GenerationType.IDENTITY;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;

@Entity
@Table(name = "category", catalog = "mkyongdb")
public class Category implements java.io.Serializable {

    private Integer categoryId;
    private String name;
    private String desc;
    private Set<StockCategory> stockCategories = new HashSet<StockCategory>(0);

    public Category() {
    }

    public Category(String name, String desc) {
        this.name = name;
        this.desc = desc;
    }

    public Category(String name, String desc, Set<StockCategory> stockCategories) {
        this.name = name;
        this.desc = desc;
        this.stockCategories = stockCategories;
    }

    @Id
    @GeneratedValue(strategy = IDENTITY)
    @Column(name = "CATEGORY_ID", unique = true, nullable = false)
    public Integer getCategoryId() {
        return this.categoryId;
    }

    public void setCategoryId(Integer categoryId) {
        this.categoryId = categoryId;
    }

    @Column(name = "NAME", nullable = false, length = 10)
    public String getName() {
        return this.name;
    }

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

    @Column(name = "[DESC]", nullable = false)
    public String getDesc() {
        return this.desc;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }

    @OneToMany(fetch = FetchType.LAZY, mappedBy = "pk.category")
    public Set<StockCategory> getStockCategories() {
        return this.stockCategories;
    }

    public void setStockCategories(Set<StockCategory> stockCategories) {
        this.stockCategories = stockCategories;
    }

}

@ManyToOne(fetch = FetchType.LAZY, mappedBy = "pk.stock", cascade=CascadeType.ALL)
private StockCategory stockgatery;

//setter and getter methods
//or something like
@ManyToOne
@JoinColumn(name="pk.stock"

@ManyToOne @JoinColumns({ @JoinColumn(name = "STOCK_ID", referencedColumnName = "STOCK_ID"), 
@JoinColumn(name = "CATEGORY_ID", referencedColumnName = "CATEGORY_ID") }) 
private StockCategory stockCategory;