ognl_ognl用于什么_java(5)

（2）OgnlRuntime.getProperty( context, source, property )获取和属性property想对应的值

8、OgnlRuntime.getProperty( context, source, property )代码：

 public static final Object getProperty( OgnlContext context, Object source, Object name ) throws OgnlException
    {
        PropertyAccessor        accessor;

        if (source == null) {
            throw new OgnlException("source is null for getProperty(null, \"" + name + "\")");
        }
        if ((accessor = getPropertyAccessor(getTargetClass(source))) == null) {
            throw new OgnlException("No property accessor for " + getTargetClass(source).getName());
        }
        return accessor.getProperty( context, source, name );
    }

注释：（1）判断source是否为空，如果为空直接抛异常，因为后面需要在 source对象中获取一些信息，所以不能为空

（2）accessor = getPropertyAccessor(getTargetClass(source))获取属性访问器对象，然后调用属性访问器的getProperty方法获取值。先看看属性访问器是怎么获得？

8.1getTargetClass(source)代码：

  public static Class getTargetClass(Object o)
    {
        return (o == null) ? null : ((o instanceof Class) ? (Class)o : o.getClass());
    }

注释：获取target所对应的class，返回结果是：class Person

8.2getPropertyAccessor(getTargetClass(source)代码：

  private static ClassCache               propertyAccessors = new ClassCache();

 public static final PropertyAccessor getPropertyAccessor( Class cls ) throws OgnlException
    {
        PropertyAccessor answer = (PropertyAccessor)getHandler( cls, propertyAccessors );
        if ( answer != null )
            return answer;

        throw new OgnlException( "No property accessor for class " + cls );
    }

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