Spring Security中的Spring Expression Language(SpEL)用于比较对象,使用equals()或==?

例如(未调用方法equals()!):

class SecurityObject {
   public boolean equals(Object obj) {
  //...
   }
 }

@PreAuthorize(" #secObject == #otherSecObject ")
public void securityMethod(SecurityObject secObject, SecurityObject otherSecObject) {
   //...
}

这是正常的!?我需要在任何地方使用@PreAuthorize(“#secObject.equals(#otherSecObject)”)吗?

更新

为什么在第一种情况下Spring Security调用.equals(),而在第二种情况下则没有呢?
      //TestObject

      public class TestObject {

      private static final Logger log = LoggerFactory.getLogger(TestObject.class);

      private Long id;

      public TestObject(Long id) {
           this.id = id;
      }

       @Override
       public int hashCode() {
           int hash = 7;
           hash = 71 * hash + Objects.hashCode(this.id);
           return hash;
       }

       @Override
       public boolean equals(Object obj) {

       log.info("equals");

       if (obj == null) {
          return false;
       }

       if (getClass() != obj.getClass()) {
         return false;
       }
       final TestObject other = (TestObject) obj;
       if (!Objects.equals(this.id, other.id)) {
         return false;
       }
      return true;
  }
}

//TestService

@PreAuthorize(" #one == #two ")
public String testEqualsInAnnotation(Long one, Long two) {
    //...
}

@Override
@PreAuthorize(" #one == #two ")
public String testEqualsInAnnotation(TestObject one, TestObject two) {
    //...
}

//Test

    log.info("for Long");
    Long one = new Long(500);
    Long two = new Long(500);

    log.info("one == two: {}", (one==two)? true : false); // print false
    log.info("one equals two: {}", (one.equals(two))? true : false); // print true

    testService.testEqualsInAnnotation(one, two); //OK

    log.info("for TestObject");

    TestObject oneObj = new TestObject(new Long(500));
    TestObject twoObj = new TestObject(new Long(500));

    log.info("oneObj == twoObj: {}", (oneObj==twoObj)? true : false); // print false
    log.info("oneObj equals twoObj: {}", (oneObj.equals(twoObj))? true : false); // print true

    testService.testEqualsInAnnotation(oneObj, twoObj); // AccessDeniedException: Access is denied

更新2

equals()从未完全调用过
           package org.springframework.expression.spel.ast;

           import org.springframework.expression.EvaluationException;
           import org.springframework.expression.spel.ExpressionState;
           import org.springframework.expression.spel.support.BooleanTypedValue;

/**
 * Implements equality operator.
 *
 * @author Andy Clement
 * @since 3.0
 */
public class OpEQ extends Operator {

    public OpEQ(int pos, SpelNodeImpl... operands) {
        super("==", pos, operands);
    }

    @Override
    public BooleanTypedValue getValueInternal(ExpressionState state) throws EvaluationException {
        Object left = getLeftOperand().getValueInternal(state).getValue();
        Object right = getRightOperand().getValueInternal(state).getValue();
        if (left instanceof Number && right instanceof Number) {
            Number op1 = (Number) left;
            Number op2 = (Number) right;
            if (op1 instanceof Double || op2 instanceof Double) {
                return BooleanTypedValue.forValue(op1.doubleValue() == op2.doubleValue());
            } else if (op1 instanceof Long || op2 instanceof Long) {
                return BooleanTypedValue.forValue(op1.longValue() == op2.longValue());
            } else {
                return BooleanTypedValue.forValue(op1.intValue() == op2.intValue());
            }
        }
        if (left!=null && (left instanceof Comparable)) {
            return BooleanTypedValue.forValue(state.getTypeComparator().compare(left, right) == 0);
        } else {
            return BooleanTypedValue.forValue(left==right);
        }
    }

}

最佳答案

根据spEL文档,您需要创建ExpressionParser实例,创建Expression实例并获取如下所示的值

String name = "Nikola Tesla";
Expression exp = parser.parseExpression("name == 'Nikola Tesla'");
boolean result = exp.getValue(Boolean.class);

结果评估为“真”。那就是说,当我们需要比较任何两个对象时,我们需要重写equals()方法并将这两个对象传递给parser#parseExpression(“obj1 == obj2”),然后调用exp#getValue(Boolean.class)进行求值。以类似的方式,Expression实例还可以具有包含Obj1.equals(Obj2)的表达式字符串,用于检查是否相等。因此,两种检查均等性的方法都可以通过spEL进行。

10-05 23:06
查看更多