"".equals(object)和object.equals("")问题

xiaoxiao2021-02-28  110

if (!"".equals(crmKhDTO.getDsdlzh())) { crmKhSwkzxxDTO.setDsdlzh(crmKhDTO.getDsdlzh()); }

能预防crmKhDTO.getDsdlzh()空指针问题

if(crmKhDTO.getDsdlzh().equals("")){ crmKhSwkzxxDTO.setDsdlzh(crmKhDTO.getDsdlzh()); }

若crmKhDTO.getDsdlzh()为null,会报空指针


注意对象要放在后边

if(StringUtils.isEmpty(jcdzOrder.getIsNeedRecepit()) || "".equals(jcdzOrder.getIsNeedRecepit())|| "Y".equals(jcdzOrder.getIsNeedRecepit()))

测试方法:

public static void main(String[] args) { String a = "aa"; String b = null; String c = ""; String d = " " ; String e ; System.out.println(StringUtils.isEmpty(a)); System.out.println(StringUtils.isEmpty(b)); System.out.println(StringUtils.isEmpty(c)); System.out.println(StringUtils.isEmpty(d)); //System.out.println(StringUtils.isEmpty(e)); System.out.println(); System.out.println("".equals(a)); System.out.println("".equals(b)); System.out.println("".equals(c)); System.out.println("".equals(d)); //System.out.println("".equals(e)); }

结果:

false true true false false false true false
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