Lesson: Members课程：成员

Reflection defines an interface java.lang.reflect.Member which is implemented by java.lang.reflect.Field, java.lang.reflect.Method, and java.lang.reflect.Constructor . 反射定义了一个接口java.lang.reflect.Member，它由java.lang.reflect.Field、java.lang.reflect.Method和java.lang.reflect.Constructor实现。These objects will be discussed in this lesson. 本课程将讨论这些对象。For each member, the lesson will describe the associated APIs to retrieve declaration and type information, any operations unique to the member (for example, setting the value of a field or invoking a method), and commonly encountered errors. 对于每个成员，本课程将描述检索声明和类型信息的相关API、成员特有的任何操作（例如，设置字段值或调用方法）以及常见错误。Each concept will be illustrated with code samples and related output which approximate some expected reflection uses.每个概念都将用代码示例和相关输出进行说明，这些示例和输出将近似于预期的反射用途。

Fields领域

Fields have a type and a value. 字段有一个类型和一个值。The java.lang.reflect.Field class provides methods for accessing type information and setting and getting values of a field on a given object.java.lang.reflect.Field类提供了访问类型信息、设置和获取给定对象上字段值的方法。

• Obtaining Field Types获取字段类型 describes how to get the declared and generic types of a field描述如何获取字段的声明类型和泛型类型
• Retrieving and Parsing Field Modifiers检索和分析字段修饰符 shows how to get portions of the field declaration such as public or transient演示如何获取字段声明的某些部分，例如public或transient
• Getting and Setting Field Values获取和设置字段值 illustrates how to access field values演示如何访问字段值
• Troubleshooting故障排除 describes some common coding errors which may cause confusion描述一些可能导致混淆的常见编码错误

Methods方法

Methods have return values, parameters, and may throw exceptions. 方法具有返回值、参数，并且可能引发异常。The java.lang.reflect.Method class provides methods for obtaining the type information for the parameters and return value. It may also be used to invoke methods on a given object.java.lang.reflect.Method类提供了获取参数和返回值的类型信息的方法。它还可以用于调用给定对象上的方法。

• Obtaining Method Type Information获取方法类型信息 shows how to enumerate methods declared in a class and obtain type information演示如何枚举类中声明的方法并获取类型信息
• Obtaining Names of Method Parameters获取方法参数的名称 shows how to retrieve names and other information of a method or constructor's parameters演示如何检索方法或构造函数参数的名称和其他信息
• Retrieving and Parsing Method Modifiers检索和解析方法修饰符 describes how to access and decode modifiers and other information associated with the method描述如何访问和解码修饰符以及与该方法相关的其他信息
• Invoking Methods调用方法 illustrates how to execute a method and obtain its return value说明如何执行方法并获取其返回值
• Troubleshooting故障排除 covers common errors encountered when finding or invoking methods涵盖查找或调用方法时遇到的常见错误

Constructors构造函数

The Reflection APIs for constructors are defined in java.lang.reflect.Constructor and are similar to those for methods, with two major exceptions: first, constructors have no return values; second, the invocation of a constructor creates a new instance of an object for a given class.构造函数的反射API在java.lang.reflect.Constructor中定义，与方法的反射API类似，但有两个主要例外：第一，构造函数没有返回值；其次，调用构造函数为给定类创建对象的新实例。

• Finding Constructors寻找构造函数 illustrates how to retrieve constructors with specific parameters演示如何检索具有特定参数的构造函数
• Retrieving and Parsing Constructor Modifiers检索和解析构造函数修饰符 shows how to obtain the modifiers of a constructor declaration and other information about the constructor演示如何获取构造函数声明的修饰符以及有关构造函数的其他信息
• Creating New Class Instances创建新的类实例 shows how to instantiate an instance of an object by invoking its constructor演示如何通过调用对象的构造函数来实例化对象的实例
• Troubleshooting故障排除 describes common errors which may be encountered while finding or invoking constructors描述在查找或调用构造函数时可能遇到的常见错误