当可能存在空指针时，如何避免冗余的try-catch语句？

Question

public class Shop {
    public metadata metadata;
    public String nameZh;
    public String nameEn;
    public String type;
    public String hash;

    public class metadata{
        public String typeEn;
        public String typeZh;

        public String getTypeEn() { return this.typeEn; }
        public String getTypeZh() { return this.typeZh; }
    }

    public metadata getMetadata() { return this.metadata; }
    public String getNameZh() { return this.nameZh; }
    public String getNameEn() { return this.nameEn; }
    public String getType() { return this.type; }
    public String getHash() { return  this.hash; }
    public String toString() {
        return getMetadata().getTypeEn()+", "+getMetadata().getTypeZh()+", "
                +getNameZh()+", "+getNameEn()+", "+ getType()+", "+getHash();
    }
}
 

Exception in thread "main" java.lang.NullPointerException: Cannot invoke "Shop$metadata.getTypeEn()" because the return value of "Shop.getMetadata()" is null
    at xlsxWorker.writeShop(xlsxWorker.java:77)
    at xlsxWorker.writeOutput(xlsxWorker.java:51)

private static void writeShop(Row current, Shop shop){
        Cell cell = current.createCell(0);
        try{
            cell.setCellValue(shop.getMetadata().getTypeEn());
        }catch (NullPointerException e){
            cell.setCellValue("null");
        }
        cell = current.createCell(1);
        try{
            cell.setCellValue(shop.getMetadata().getTypeZh());
        }catch (NullPointerException e){
            cell.setCellValue("null");
        }
        cell = current.createCell(2);
        try{
            cell.setCellValue(shop.getNameZh());
        }catch (NullPointerException e){
            cell.setCellValue("null");
        }
        cell = current.createCell(3);
        try{
            cell.setCellValue(shop.getNameEn());
        }catch (NullPointerException e){
            cell.setCellValue("null");
        }
        cell = current.createCell(4);
        try{
            cell.setCellValue(shop.getType());
        }catch (NullPointerException e){
            cell.setCellValue("null");
        }
        cell = current.createCell(5);
        try{
            cell.setCellValue(shop.getHash());
        }catch (NullPointerException e){
            cell.setCellValue("null");
        }
    }

我如何避免在这里过度使用试捕？我如何简化裁员

Answer 1

您可以使用默认值初始化Pojo，如

1. 空字符串“”
2. null作为字符串文本“null”

更新

if(shop.getMetadata() != null)
{ 
//your brilliant code 
}