在下面的代码块中，我正在尝试打印location类中定义的monthlyRent，numberOfBedrooms，Property等于此方法参数的属性在LettingAgent类中。当我编译时，错误发生在if行中，它表示无法从静态上下文引用非getlocation()等非静态方法。
/**
* Java coursework on class property which present detail information about the property
public class Property
{
// instance variables of class property.
private String address;
private char location;
private double monthlyRent;
private int numberOfBedrooms;
private boolean occupied;
private String tenantName;
/**
* Constructor for object of class Property with required parameters.
*/
public Property( String addressinput, char locationinput, double Rentinput, int Bedsinput )
{
//initialise the instance variables or fields of property class.
address = addressinput;
location = locationinput;
monthlyRent = Rentinput;
numberOfBedrooms = Bedsinput;
occupied = false;
tenantName = "";
}
/**
* Return the address of the property
*/
public String getAdress( )
{
return address;
}
/**
* Return the location of the property
*/
public char getLocation( )
{
return location;
}
/**
* Return the monthlyRent of the property
*/
public double getmonthlyRent( )
{
return monthlyRent;
}
/**
* Return the numberOfBedrooms of the property
*/
public int getnumberOfBedrooms( )
{
return numberOfBedrooms;
}
/**
* Return the occupied value of the property
*/
public boolean isoccupied( )
{
return occupied;
}
/**
* Return the tenant's name of the property
*/
public String gettenantName( )
{
return tenantName;
}
/**
* Set the monthly rent to a new value
*/
public void setmonthlyRent( double newRent )
{
monthlyRent = newRent;
}
/**
* Adding tenant's name to the property
*/
public void addtenantName(String newTenant)
{
if(occupied == false) {
tenantName = newTenant;
occupied = true;
}
else {
System.out.println(" The property is already occupied");
}
}
/**
* Removing tenant's name of the property
*/
public void removetenantName( )
{
if( occupied == true) {
tenantName = "";
occupied = false;
}
else {
System.out.println(" The property is new and not occupied");
}
}
/**
* Print all the property attributes
*/
public void printProperty( )
{
//simulate the printing of the property attributes.
System.out.println( "The details of the property are as follow" );
System.out.println("Address:" + address );
switch(location){
case 'n': case 'N': System.out.println("Location: North london" );break;
case 's': case 'S': System.out.println("Location: South london" );break;
case 'e': case 'E': System.out.println("Location: East london" );break;
case 'w': case 'W': System.out.println("Location: West london" );
}
System.out.println("Monthly-Rent:" + monthlyRent );
System.out.println("Number of Bedrooms:" + numberOfBedrooms );
System.out.println("Status of property:" + occupied );
if(occupied == true) {
System.out.println("Tenant Name:" + tenantName );
}
else {
System.out.println("Property is empty at moment" );
}
}
}
LettingAgent Class（调用类）
import java.util.ArrayList;
/**
* Write a description of class LettingAgent here.
*/
public class LettingAgent
{
// instance variables of LettingAgent Class.
private ArrayList<Property>agproperty;
private int Propnumber;
/**
* Constructor for objects of class LettingAgent
*/
public LettingAgent()
{
// initialise instance variables
agproperty = new ArrayList<Property>();
Propnumber = 0;
}
/**
* Return the property number of the Class LettingAgent.
*/
public int getPropnumber(){
return Propnumber;
}
/**
*Method to add new property to the class LettingAgent via class Property.
*/
public void addNewProperty(String addressinput, char locationinput, double Rentinput, int Bedsinput)
{
// put your code here
Property newProperty = new Property(addressinput,locationinput,Rentinput,Bedsinput);
agproperty.add(newProperty);
}
/**
* @Description Method for removing the propety from the class LettingAgent.
* @param int propnumber
*/
public void removalOfProperty(int Propnumber)
{
// initialise instance variables
if( Propnumber<agproperty.size()){
agproperty.remove(Propnumber);
System.out.println("The property has been removed");
}
else{
System.out.println("The Property number is not valid");
}
}
/**
* Method for adding tenant to the property within class LettingAgent via class Property.
*/
public void addTenant(int Propnumber, String newName, Property newProperty)
{
// initialise instance variables
if( Propnumber<agproperty.size()){
agproperty.get(Propnumber);
newProperty.addtenantName(newName);
}
else{
System.out.println("The Property number is not valid");
}
}
/**
* Method for removing tenant from the class LettingAgent via Property class.
*/
public void removeTenant(int Propnumber,Property newProperty)
{
// initialise instance variables
if( Propnumber<agproperty.size()){
agproperty.get(Propnumber);
newProperty.removetenantName( );
}
else{
System.out.println("The Property number is not valid");
}
}
/**
*Method for searching property within the LettingAgent class.
*/
public void searchProperty(String Address)
{
// initialise instance variables
for(Property Property : agproperty){
if (agproperty.get(Propnumber).equals( Address)){
System.out.println("The details of the property is as follow"+ Property);
}
else{
System.out.println("The property is not in the Letting agent's Stock");
}
}
}
/**
* Method for printing unoccupied property of the class LettingAgent.
*/
public void printListOfUnoccupiedProperty( char Location, double maxmonthlyRent, int miniNoBeds)
{
// initialise instance variables
for(Property property : agproperty){
if((Property.getLocation().equals(Location))&&(Property.get(monthlyRent).equals(maxmonthlyRent))&&(agproperty.get(numberOfBedrooms).equals(miniNoBeds))){
System.out.Println(Propnumber);
Property.printProperty();
}
else{
System.out.println("The Property number is not valid");
}
}
}
}
答案 0 :(得分：2)
在您定义的最后一个方法中（格式如下）：
/**
* Method for printing unoccupied property of the class LettingAgent.
*/
public void printListOfUnoccupiedProperty(char Location, double maxmonthlyRent, int miniNoBeds) {
// initialise instance variables
for (Property Property : agproperty) {
if ((Property.getLocation().equals(Location))
&& (Property.get(monthlyRent).equals(maxmonthlyRent))
&& (agproperty.get(numberOfBedrooms).equals(miniNoBeds))) {
System.out.Println(Propnumber);
Property.printProperty();
} else {
System.out.println("The Property number is not valid");
}
}
}
就行：
&& (Property.get(monthlyRent).equals(maxmonthlyRent))
您正在调用get变量的Property方法。我认为那应该是Property.getMonthlyRent()。
另一件事，在Java中，您应该以与其类名不同的方式命名变量。我会使用像
这样的东西for (Property property : agproperty) { ...
我知道这是一个很小的改变，但它对你的代码的可读性产生了很大的影响。您可以在Code Conventions for the Java Programming Language中阅读其他Java代码约定。
答案 1 :(得分：2)
好的，我现在已经在BlueJ中编译了你的代码，这就是我发现的。首先我收到错误消息
non-static method getLocation() cannot be referenced from a static context
在以下行中将变量名称从Property更改为property时：
for(Property property : agproperty){
您还需要在下一行中引用它的地方进行更改：
if((Property.getLocation().equals(Location))&& ...
单词Property现在只引用类名，因此短语Property.getLocation()看起来像一个静态方法调用。您需要将其更改为：
if((property.getLocation().equals(Location))&& ...
请注意property的小写字母。
接下来还有一些需要修复的方法调用，如Property.get(monthlyRent)。同样，您需要将变量名称更改为property并将正确的方法名称放入。
之后我收到错误消息：
char cannot be dereferenced
这意味着您正在尝试在原语 char类型的变量上调用方法。你在同一个方法的开头就是这样做的：
property.getLocation().equals(Location) ...
您不能在equals上使用char方法，因为它是基本类型，而不是对象类型。 （你用什么来比较两个原语？）
当您尝试比较两个double值时，您会再次执行相同的操作。
property.getmonthlyRent().equals(maxmonthlyRent)
接下来你有：
agproperty.get(numberOfBedrooms).equals(miniNoBeds)
这里的问题有点复杂。看起来你在这个短语的开头有一个错误的变量名。想想你想要在这里比较什么，看看你修复过的前两个问题，我想你可以找出应该在这里的内容。