java-自动生成值对象

给定一个或多个接口,生成类实现的最佳方法是什么？

interface Vehicle
{
    Engine getEngine();
}

@Generated
class Car implements Vehicle
{
    private final Engine engine;

    public Car(Engine engine)
    {
        this.engine = engine;
    }

    public Engine getEngine()
    {
        return engine;
    }

    // generated implementation of equals, hashCode, toString, 
}

类变量应从接口的getter方法派生.理想情况下,将处理接口中的协变返回类型.该实现应通过使用私有最终变量和构造函数实例化来实现不变性. equals,hashCode和toString方法应生成.

解决方法:

更干净的方法是使用CGLIB在运行时动态生成类.显然,您无法浏览源文件.

如果需要源文件,可以尝试codemodel并执行以下操作：

JCodeModel cm = new JCodeModel();
x = cm._class("foo.bar.Car");
x.field(Engine.class, "engine");
for (PropertyDescriptor pd:    Introspector.
              getBeanInfo(Vehicle.class).getPropertyDescriptors()) {
    g = x.method(JMod.PUBLIC, cm.VOID, pd.getReaderMethod().getName()); 
    g.body()...
    s = x.method(JMod.PUBLIC, cm.VOID, "set" + pd.getName());
    s.body()...
}
hc = x.method(JMod.PUBLIC, cm.VOID, "hashCode"));
hc.body()...
cm.build(new File("target/generated-sources"));

或按照之前的建议,使用IDE(在Eclipse中：菜单“源”,“生成hashcode()和equals()…”,即)

标签：compile-time,annotations,code-generation,runtime,java
来源： https://codeday.me/bug/20191024/1921265.html