11.Bean2Document-BEAN转document

1.

package com.glodon.gspm.adapter.plugin.common;

import com.glodon.cloudt.tenancy.context.TenantContext;
import org.bson.Document;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.BeanWrapper;
import org.springframework.beans.PropertyAccessorFactory;
import org.springframework.util.StringUtils;

import java.beans.PropertyDescriptor;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * 实体对象转Document类
 * Created by hezg on 2017/4/4.
 */
public class Bean2Document<T> {

    //字段前缀
    private static final char COLUMN_PREFIX = 'F';
    //单词分隔符
    private static final char UNDER_LINE = '_';
    //字段属性映射
    private transient Map<String, PropertyDescriptor> mappedFields;

    private static Map<Class<?>, Bean2Document> mapperMap = new ConcurrentHashMap<>();

    public Bean2Document(Class<T> mappedClass) {
        initialize(mappedClass);
    }

    /**
     * 创建一个新的Bean2Document类
     *
     * @param mappedClass 需要映射的实体类
     */
    @SuppressWarnings("unchecked")
    public static <T> Bean2Document<T> newInstance(Class<T> mappedClass) {
        Bean2Document mapper = mapperMap.get(mappedClass);
        if (mapper == null) {
            mapper = new Bean2Document<>(mappedClass);
            mapperMap.put(mappedClass, mapper);
        }
        return (Bean2Document<T>) mapper;
    }

    /**
     * 将实体属性初始化到mappedFields中
     *
     * @param mappedClass 需要初始化的实体类
     */
    @SuppressWarnings("Duplicates")
    protected void initialize(Class<T> mappedClass) {
        this.mappedFields = new HashMap<>();
        PropertyDescriptor[] pds = BeanUtils.getPropertyDescriptors(mappedClass);
        for (PropertyDescriptor pd : pds) {
            if (pd.getWriteMethod() != null) {
                this.mappedFields.put(pd.getName().toUpperCase(), pd);
            }
        }
    }

    /**
     * 将实体字段名转换为表字段名
     *
     * @param name 实体字段
     * @return 返回对应表字段名
     */
    @SuppressWarnings("Duplicates")
    private String underscoreName(String name) {
        if (!StringUtils.hasLength(name)) {
            return "";
        }
        // 添加字段前缀
        StringBuilder result = new StringBuilder();
        if (!StringUtils.isEmpty(COLUMN_PREFIX)) {
            result.append(COLUMN_PREFIX).append(UNDER_LINE);
        }
        result.append(name.substring(0, 1).toUpperCase());
        for (int i = 1; i < name.length(); i++) {
            String ss = name.substring(i, i + 1);
            String slc = ss.toUpperCase();
            if (ss.equals(slc)) {
                result.append(UNDER_LINE).append(slc);
            } else {
                result.append(slc);
            }
        }
        return result.toString();
    }

    /**
     * 将实体数据格式转换为Document格式
     *
     * @param data 实体数据
     * @return Document格式数据
     */
    public Document toDocument(T data) {
        if (data == null) {
            return null;
        }

        Document document = new Document();
        BeanWrapper bw = PropertyAccessorFactory.forBeanPropertyAccess(data);
        for (PropertyDescriptor pd : this.mappedFields.values()) {
            Object value = bw.getPropertyValue(pd.getName());
            String underscoredName = underscoreName(pd.getName());
            document.put(underscoredName, value);
        }
        //Mongo同一接口，所有类转Document时都带上租户Id
        long tenantId = TenantContext.getCurrent()
                .getTenantId();

        document.put("F_TENANT_ID", tenantId);
        return document;
    }
}