java.lang.NullPointerException错误
我是Java的初学者我一直在犯这个错误。。java.lang.NullPointerException指向此行-->Double hOption=healthBendSig.get(“employeeOnly”); 有人能告诉我我是否遗漏了什么或者我到底做错了什么吗java.lang.NullPointerException错误,java,Java,我是Java的初学者我一直在犯这个错误。。java.lang.NullPointerException指向此行-->Double hOption=healthBendSig.get(“employeeOnly”); 有人能告诉我我是否遗漏了什么或者我到底做错了什么吗 private HashMap<String, Double> healthBenDesig; public VariableList() { HashMap<String, Double&g
private HashMap<String, Double> healthBenDesig;
public VariableList()
{
HashMap<String, Double> healthBenDesig = new HashMap<String, Double>();
}
public VariableList()
{
HashMap<String, Double> healthBenDesig = new HashMap<String, Double>();
}
public void getHMP()
{
Double hOption = healthBenDesig.get("employeeOnly");
System.out.println("The health Option you chose is: " + hOption);
}
public HashMap setHealthOpt()
{
healthBenDesig.put("none", 0.00);
healthBenDesig.put("employeeOnly", 311.87);
healthBenDesig.put("spouse", 592.56);
healthBenDesig.put("children", 717.30);
healthBenDesig.put("kids", 882.60);
System.out.println(healthBenDesig);
return healthBenDesig;
}
私有HashMap-sig;
公共变量列表()
{
HashMap healthBenDesig=新HashMap();
}
公共变量列表()
{
HashMap healthBenDesig=新HashMap();
}
public void getHMP()
{
Double hOption=HealthBendsig.get(“仅限员工”);
System.out.println(“您选择的健康选项是:“+hOption”);
}
公共HashMap setHealthOpt()
{
Healthbendsig.put(“无”,0.00);
Healthbendsig.put(“仅限员工”,311.87);
Healthbendsig.put(“配偶”),592.56;
Healthbendsig.put(“儿童”),717.30;
Healthbendsig.put(“儿童”,882.60);
System.out.println(healthbendsig);
返回信号;
}
通过在构造函数中重新声明healthBenDesig,将类字段保留为null,从而隐藏healthBenDesig。不要再申报了
改变
public VariableList() {
HashMap<String, Double> healthBenDesig = new HashMap<String, Double>();
}
公共变量列表(){
HashMap healthBenDesig=新HashMap();
}
致:
公共变量列表(){
healthBenDesig=newhashmap();
}
通过在构造函数中重新声明healthBenDesig,将类字段保留为null,从而隐藏healthBenDesig。不要再申报了
改变
public VariableList() {
HashMap<String, Double> healthBenDesig = new HashMap<String, Double>();
}
公共变量列表(){
HashMap healthBenDesig=新HashMap();
}
致:
公共变量列表(){
healthBenDesig=newhashmap();
}
您没有初始化类成员healthBenDesig,而是使用lcoal变量对其进行跟踪。这导致HealthBendsig未初始化,并导致NullPointerException
。在构造函数中,将其从
public VariableList()
{
// re-declaration or shadowing of memeber variable healthBenDesig
HashMap<String, Double> healthBenDesig = new HashMap<String, Double>();
}
公共变量列表()
{
//重新声明或隐藏memeber变量healthBenDesig
HashMap healthBenDesig=新HashMap();
}
到
公共变量列表()
{
healthBenDesig=newhashmap();
}
您没有初始化类成员healthBenDesig,而是使用lcoal变量对其进行跟踪。这导致HealthBendsig未初始化,并导致NullPointerException
。在构造函数中,将其从
public VariableList()
{
// re-declaration or shadowing of memeber variable healthBenDesig
HashMap<String, Double> healthBenDesig = new HashMap<String, Double>();
}
公共变量列表()
{
//重新声明或隐藏memeber变量healthBenDesig
HashMap healthBenDesig=新HashMap();
}
到
公共变量列表()
{
healthBenDesig=newhashmap();
}
您可以在属性声明中初始化HealthBendSig
private HashMap<String, Double> healthBenDesig = new HashMap<String, Double>();
private HashMap healthbendsig=new HashMap();
您可以在属性声明中初始化HealthBendSig
private HashMap<String, Double> healthBenDesig = new HashMap<String, Double>();
private HashMap healthbendsig=new HashMap();
谢谢”按钮就是您在答案左侧看到的记号。它告诉每个人你的问题已经得到了令人满意的答案,不需要进一步的回答。“谢谢”按钮就是你在答案左边看到的勾号。它告诉每个人你的问题已经得到了满意的答案,不需要进一步的回答。