带有复合主键的Spring数据表

从为具有复合ID的实体定制HATEOAS链接生成中学习后，我发现了一个更为通用的解决方案。

首先，创建一个SpringUtil以从Spring获取bean。

import org.springframework.beans.BeansException;import org.springframework.context.ApplicationContext;import org.springframework.context.ApplicationContextAware;import org.springframework.stereotype.Component;@Componentpublic class SpringUtil implements ApplicationContextAware {    private static ApplicationContext applicationContext;    @Override    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {        if(SpringUtil.applicationContext == null) { SpringUtil.applicationContext = applicationContext;        }    }    public static ApplicationContext getApplicationContext() {        return applicationContext;    }    public static Object getBean(String name){        return getApplicationContext().getBean(name);    }    public static <T> T getBean(Class<T> clazz){        return getApplicationContext().getBean(clazz);    }    public static <T> T getBean(String name,Class<T> clazz){        return getApplicationContext().getBean(name, clazz);    }}

然后，实现BackendIdConverter。

import com.alibaba.fastjson.JSON;import com.example.SpringUtil;import org.springframework.data.jpa.repository.JpaRepository;import org.springframework.data.rest.webmvc.spi.BackendIdConverter;import org.springframework.stereotype.Component;import javax.persistence.EmbeddedId;import javax.persistence.Id;import java.io.Serializable;import java.io.UnsupportedEncodingException;import java.lang.reflect.Method;import java.net.URLDeprer;import java.net.URLEnprer;@Componentpublic class CustomBackendIdConverter implements BackendIdConverter {    @Override    public boolean supports(Class<?> delimiter) {        return true;    }    @Override    public Serializable fromRequestId(String id, Class<?> entityType) {        if (id == null) { return null;        }        //first depre url string        if (!id.contains(" ") && id.toUpperCase().contains("%7B")) { try {     id = URLDeprer.depre(id, "UTF-8"); } catch (UnsupportedEncodingException e) {     e.printStackTrace(); }        }        //deserialize json string to ID object        Object idObject = null;        for (Method method : entityType.getDeclaredMethods()) { if (method.isAnnotationPresent(Id.class) || method.isAnnotationPresent(EmbeddedId.class)) {     idObject = JSON.parseObject(id, method.getGenericReturnType());     break; }        }        //get dao class from spring        Object daoClass = null;        try { daoClass = SpringUtil.getBean(Class.forName("com.example.db.dao." + entityType.getSimpleName() + "DAO"));        } catch (ClassNotFoundException e) { e.printStackTrace();        }        //get the entity with given primary key        JpaRepository simpleJpaRepository = (JpaRepository) daoClass;        Object entity = simpleJpaRepository.findOne((Serializable) idObject);        return (Serializable) entity;    }    @Override    public String toRequestId(Serializable id, Class<?> entityType) {        if (id == null) { return null;        }        String jsonString = JSON.toJSonString(id);        String enpredString = "";        try { enpredString = URLEnprer.enpre(jsonString, "UTF-8");        } catch (UnsupportedEncodingException e) { e.printStackTrace();        }        return enpredString;    }}

之后。你可以做你想做的。

下面有一个示例。

• 如果实体具有单个属性pk，则可以正常使用localhost：8080 / demo / 1。根据我的代码，假设pk具有注释“ @Id”。
• 如果实体由pk组成，假设pk是demoId类型，并且具有注释“ @EmbeddedId”，则可以使用localhost：8080 / demo / {demoId json}进行获取/放置/删除。并且您的自我链接将是相同的。