List多对多的查询应用

/**
     * @param param
     * @author mercy 查询主副产品(主副产品是多对多的关系)
     * @return
     */
    public String queryProductSpecAttr(JSONObject param){
    	ResultInfo result = new ResultInfo(0,"success","");
		Grid grid = new Grid();
    	String productSpecId=param.getString("productSpecId");
    	ProductSpec ps=productSpecDao.findByProductSpecId(productSpecId);
    	String prodCode=ps.getProdCode();//prodCode相同的话则可能存在主副产品
    	int prodType=ps.getProdType(); //主副产品标识(0:主产品,1:附属产品)
    	//查当前产品属性
    	List<ProductSpecAttr> productSpecAttrList=productSpecAttrDao.findByProductSpecId(productSpecId);
    	//产品属性List
    	List<ProductDto> listPsaList=new ArrayList<ProductDto>() ;
    	//主产品
    	if(prodType==0){
    		//主产品属性
    		ProductDto mainDto=new ProductDto();
    		mainDto.setMainList(productSpecAttrList);
    		mainDto.setProductName(ps.getName());
    		mainDto.setProductSpecId(ps.getProductSpecId());
    		//存主主产品属性,名称
    		listPsaList.add(mainDto);
    		//查出附属产品
    		List<ProductSpec> psSubList=productSpecDao.findByProdCodeAndProdType(prodCode,1);
    		if(psSubList.size()>0){
    			//查附属产品数据
    			for(ProductSpec psl:psSubList){
    				Integer productId = psl.getId();
    				if(ps.getId()!=productId){
    					ProductDto subDto=new ProductDto();
    					List<ProductSpecAttr> psaSubList=productSpecAttrDao.findByProductSpecId(psl.getProductSpecId());
    					subDto.setSubList(psaSubList);
    					subDto.setProductName(psl.getName());
    					subDto.setProductSpecId(psl.getProductSpecId());
    					//附属产品属性,名称
    					listPsaList.add(subDto);
    				}
    			}
    		}
    	//附属产品
    	}else if(prodType==1){
    		ProductDto subDto=new ProductDto();
    		List<ProductSpec> psMainList=productSpecDao.findByProdCodeAndProdType(prodCode,0);
    		//存附属产品名称
    		subDto.setProductName(ps.getName());
    		subDto.setProductSpecId(ps.getProductSpecId());
    		//存附属产品属性
    		subDto.setSubList(productSpecAttrList);
    		//存附属产品属性,名称
    		listPsaList.add(subDto);
    		if(psMainList.size()>0){
    			//查主产品数据
    			for(ProductSpec psl:psMainList){
    				Integer productId = psl.getId();
    				if(ps.getId()!=productId){
    					ProductDto mainDto=new ProductDto();
    					List<ProductSpecAttr> psaMainList=productSpecAttrDao.findByProductSpecId(psl.getProductSpecId());
    					mainDto.setProductName(psl.getName());
    					mainDto.setProductSpecId(psl.getProductSpecId());
    					mainDto.setMainList(psaMainList);
    					//主产品属性,名称
    					listPsaList.add(mainDto);
    				}
    			}
    		}
    	}
    	grid.setContent(listPsaList);
    	result.setResult_data(JSONObject.toJSONString(grid));
    	return JSONObject.toJSONString(result);
    }

package com.eshore.ismp.product.dto;

import java.util.List;

import com.eshore.ismp.product.model.ProductSpecAttr;

public class ProductDto {
	private String productName;
	private String productSpecId;
	private List<ProductSpecAttr> subList;
	private List<ProductSpecAttr> mainList;
	
	public String getProductName() {
		return productName;
	}

	public void setProductName(String productName) {
		this.productName = productName;
	}
	
	public String getProductSpecId() {
		return productSpecId;
	}

	public void setProductSpecId(String productSpecId) {
		this.productSpecId = productSpecId;
	}

	public List<ProductSpecAttr> getSubList() {
		return subList;
	}

	public void setSubList(List<ProductSpecAttr> subList) {
		this.subList = subList;
	}

	public List<ProductSpecAttr> getMainList() {
		return mainList;
	}

	public void setMainList(List<ProductSpecAttr> mainList) {
		this.mainList = mainList;
	}
}