增加翻页特性并修正部分格式 (clxering#70)

Chapter-2/Chapter-2-Introduction.md

@@ -5,3 +5,14 @@
 This chapter concerns（关注、涉及） creating and destroying objects: when and how to create them, when and how to avoid creating them, how to ensure they are destroyed in a timely manner, and how to manage any cleanup actions that must precede their destruction.
 
 本章涉及创建和销毁对象：何时以及如何创建对象，何时以及如何避免创建对象，如何确保它们被及时销毁，以及如何管理在销毁之前必须执行的清理操作。
+
+### Contents of the chapter（章节目录）
+- [Item 1: Consider static factory methods instead of constructors（考虑以静态工厂方法代替构造函数）](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Item-1-Consider-static-factory-methods-instead-of-constructors.md)
+- [Item 2: Consider a builder when faced with many constructor parameters（在面对多个构造函数参数时，请考虑构建器）](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Item-2-Consider-a-builder-when-faced-with-many-constructor-parameters.md)
+- [Item 3: Enforce the singleton property with a private constructor or an enum type（使用私有构造函数或枚举类型实施单例属性）](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Item-3-Enforce-the-singleton-property-with-a-private-constructor-or-an-enum-type.md)
+- [Item 4: Enforce noninstantiability with a private constructor（用私有构造函数实施不可实例化）](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Item-4-Enforce-noninstantiability-with-a-private-constructor.md)
+- [Item 5: Prefer dependency injection to hardwiring resources（依赖注入优于硬连接资源）](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Item-5-Prefer-dependency-injection-to-hardwiring-resources.md)
+- [Item 6: Avoid creating unnecessary objects（避免创建不必要的对象）](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Item-6-Avoid-creating-unnecessary-objects.md)
+- [Item 7: Eliminate obsolete object references（排除过时的对象引用）](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Item-7-Eliminate-obsolete-object-references.md)
+- [Item 8: Avoid finalizers and cleaners（避免使用终结器和清除器）](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Item-8-Avoid-finalizers-and-cleaners.md)
+- [Item 9: Prefer try with resources to try finally（使用 try-with-resources 优于 try-finally）](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Item-9-Prefer-try-with-resources-to-try-finally.md)

Chapter-2/Chapter-2-Item-1-Consider-static-factory-methods-instead-of-constructors.md

@@ -14,15 +14,15 @@ public static Boolean valueOf(boolean b) {
 
 Note that a static factory method is not the same as the Factory Method pattern from Design Patterns [Gamma95]. The static factory method described in this item has no direct equivalent in Design Patterns.
 
-要注意的是静态工厂方法与来自设计模式的工厂方法模式不同[Gamma95]。本项目中描述的静态工厂方法在设计模式中没有直接等价的方法。
+要注意的是静态工厂方法与来自设计模式的工厂方法模式不同 [Gamma95]。本项目中描述的静态工厂方法在设计模式中没有直接等价的方法。
 
 A class can provide its clients with static factory methods instead of, or in addition to（除了）, public constructors. Providing a static factory method instead of a public constructor has both advantages and disadvantages.
 
 除了公共构造函数，一个类还可以通过静态工厂方法提供它的客户端。提供静态工厂方法而不是公共构造函数的方式既有优点也有缺点。
 
 **One advantage of static factory methods is that, unlike constructors, they have names.** If the parameters to a constructor do not, in and of themselves,describe the object being returned, a static factory with a well-chosen name is easier to use and the resulting client code easier to read. For example, the constructor BigInteger(int, int, Random), which returns a BigInteger that is probably prime, would have been better expressed as a static factory method named BigInteger.probablePrime. (This method was added in Java 4.)
 
-**静态工厂方法与构造函数相比的第一个优点，静态工厂方法有确切名称。** 如果构造函数的参数本身并不能描述返回的对象，那么具有确切名称的静态工厂则更容易使用，生成的客户端代码也更容易阅读。例如，返回可能为素数的 BigInteger 类的构造函数 BigInteger(int, int, Random) 最好表示为名为 BigInteger.probableprime 的静态工厂方法。（这个方法是在 Java 4 中添加的）
+**静态工厂方法与构造函数相比的第一个优点，静态工厂方法有确切名称。** 如果构造函数的参数本身并不能描述返回的对象，那么具有确切名称的静态工厂则更容易使用，生成的客户端代码也更容易阅读。例如，返回可能为素数的 BigInteger 类的构造函数 `BigInteger(int, int, Random)` 最好表示为名为 `BigInteger.probableprime` 的静态工厂方法。（这个方法是在 Java 4 中添加的）
 
 A class can have only a single constructor with a given signature（n. 署名；签名；信号）.Programmers have been known to get around this restriction（n. 限制；约束；束缚） by providing two constructors whose parameter lists differ（vi. 相异；不同） only in the order of their parameter types. This is a really bad idea. The user of such an API will never be able to remember which constructor is which and will end up calling the wrong one by mistake. People reading code that uses these constructors will not know what the code does without referring to the class documentation.
 
@@ -34,11 +34,11 @@ Because they have names, static factory methods don’t share the restriction di
 
 **A second advantage of static factory methods is that, unlike constructors,they are not required to create a new object each time they’re invoked.** This allows immutable classes (Item 17) to use preconstructed instances, or to cache instances as they’re constructed, and dispense them repeatedly to avoid creating unnecessary duplicate（adj. 复制的；二重的） objects. The Boolean.valueOf(boolean) method illustrates this technique: it never creates an object. This technique is similar to the Flyweight pattern [Gamma95]. It can greatly improve performance if equivalent objects are requested often, especially if they are expensive to create.
 
-**静态工厂方法与构造函数相比的第二个优点，静态工厂方法不需要在每次调用时创建新对象。** 这允许不可变类（[Item-17](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-4/Chapter-4-Item-17-Minimize-mutability.md)）使用预先构造的实例，或在构造实例时缓存实例，并重复分配它们以避免创建不必要的重复对象。Boolean.valueOf(boolean) 方法说明了这种技术：它从不创建对象。这种技术类似于享元模式[Gamma95]。如果经常请求相同的对象，特别是在创建对象的代价很高时，它可以极大地提高性能。
+**静态工厂方法与构造函数相比的第二个优点，静态工厂方法不需要在每次调用时创建新对象。** 这允许不可变类（[Item-17](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-4/Chapter-4-Item-17-Minimize-mutability.md)）使用预先构造的实例，或在构造实例时缓存实例，并重复分配它们以避免创建不必要的重复对象。`Boolean.valueOf(boolean)` 方法说明了这种技术：它从不创建对象。这种技术类似于享元模式 [Gamma95]。如果经常请求相同的对象，特别是在创建对象的代价很高时，它可以极大地提高性能。
 
 The ability of static factory methods to return the same object from repeated invocations allows classes to maintain strict control over what instances exist at any time. Classes that do this are said to be instance-controlled. There are several reasons to write instance-controlled classes. Instance control allows a class to guarantee that it is a singleton (Item 3) or noninstantiable (Item 4). Also,it allows an immutable（adj. 不变的；不可变的；不能变的） value class (Item 17) to make the guarantee that no two equal instances exist: a.equals(b) if and only if a == b. This is the basis of the Flyweight pattern [Gamma95]. Enum types (Item 34) provide this guarantee（n.保证，保证书；vt.担保）.
 
-静态工厂方法在重复调用中能够返回相同对象，这样的能力允许类严格控制任何时候存在的实例。这样做的类被称为实例受控的类。编写实例受控的类有几个原因。实例控制允许一个类来保证它是一个单例（[Item-3](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Item-3-Enforce-the-singleton-property-with-a-private-constructor-or-an-enum-type.md)）或不可实例化的（[Item-4](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Item-4-Enforce-noninstantiability-with-a-private-constructor.md)）。同时,它允许一个不可变的值类（[Item-17](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-4/Chapter-4-Item-17-Minimize-mutability.md)）保证不存在两个相同的实例：a.equals(b) 当且仅当 a==b。这是享元模式的基础[Gamma95]。枚举类型（[Item-34](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-6/Chapter-6-Item-34-Use-enums-instead-of-int-constants.md)）提供了这种保证。
+静态工厂方法在重复调用中能够返回相同对象，这样的能力允许类严格控制任何时候存在的实例。这样做的类被称为实例受控的类。编写实例受控的类有几个原因。实例控制允许一个类来保证它是一个单例（[Item-3](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Item-3-Enforce-the-singleton-property-with-a-private-constructor-or-an-enum-type.md)）或不可实例化的（[Item-4](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Item-4-Enforce-noninstantiability-with-a-private-constructor.md)）。同时,它允许一个不可变的值类（[Item-17](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-4/Chapter-4-Item-17-Minimize-mutability.md)）保证不存在两个相同的实例：`a.equals(b)` 当且仅当 a==b。这是享元模式的基础 [Gamma95]。枚举类型（[Item-34](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-6/Chapter-6-Item-34-Use-enums-instead-of-int-constants.md)）提供了这种保证。
 
 **译注：原文 noninstantiable 应修改为 non-instantiable ，译为「不可实例化的」**
 
@@ -52,7 +52,7 @@ One application of this flexibility（n.灵活性，弹性，适应性） is tha
 
 Prior to Java 8, interfaces couldn’t have static methods. By convention, static factory methods for an interface named Type were put in a noninstantiable companion（n.同伴，指南；vt.陪伴） class (Item 4) named Types. For example, the Java Collections Framework has forty-five utility implementations of its interfaces, providing unmodifiable collections, synchronized collections, and the like. Nearly all of these implementations are exported via static factory methods in one noninstantiable class (java.util.Collections). The classes of the returned objects are all nonpublic.
 
-在 Java 8 之前，接口不能有静态方法。按照惯例，一个名为 Type 的接口的静态工厂方法被放在一个名为 Types 的不可实例化的伴随类（[Item-4](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Item-4-Enforce-noninstantiability-with-a-private-constructor.md)）中。例如，Java 的 Collections 框架有 45 个接口实用工具实现，提供了不可修改的集合、同步集合等。几乎所有这些实现都是通过一个非实例化类（java.util.Collections）中的静态工厂方法导出的。返回对象的类都是非公共的。
+在 Java 8 之前，接口不能有静态方法。按照惯例，一个名为 Type 的接口的静态工厂方法被放在一个名为 Types 的不可实例化的伴随类（[Item-4](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Item-4-Enforce-noninstantiability-with-a-private-constructor.md)）中。例如，Java 的 Collections 框架有 45 个接口实用工具实现，提供了不可修改的集合、同步集合等。几乎所有这些实现都是通过一个非实例化类（`java.util.Collections`）中的静态工厂方法导出的。返回对象的类都是非公共的。
 
 **译注：原文 noninstantiable 应修改为 non-instantiable ，译为「不可实例化的」**
 
@@ -86,7 +86,7 @@ There are three essential（n.本质，要素；adj.基本的，精华的） com
 
 An optional fourth component of a service provider framework is a service provider interface, which describes a factory object that produce instances of the service interface. In the absence of a service provider interface, implementations must be instantiated reflectively (Item 65). In the case of JDBC, Connection plays the part of the service interface, DriverManager.registerDriver is the provider registration API, DriverManager.getConnection is the service access API, and Driver is the service provider interface.
 
-服务提供者框架的第四个可选组件是服务提供者接口，它描述了产生服务接口实例的工厂对象。在没有服务提供者接口的情况下，必须以反射的方式实例化实现（[Item-65](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-9/Chapter-9-Item-65-Prefer-interfaces-to-reflection.md)）。在 JDBC 中，连接扮演服务接口 DriverManager 的角色。DriverManager.registerDriver 是提供商注册的 API，DriverManager.getConnection 是服务访问 API，驱动程序是服务提供者接口。
+服务提供者框架的第四个可选组件是服务提供者接口，它描述了产生服务接口实例的工厂对象。在没有服务提供者接口的情况下，必须以反射的方式实例化实现（[Item-65](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-9/Chapter-9-Item-65-Prefer-interfaces-to-reflection.md)）。在 JDBC 中，连接扮演服务接口 DriverManager 的角色。DriverManager.registerDriver 是提供商注册的 API，`DriverManager.getConnection` 是服务访问 API，驱动程序是服务提供者接口。
 
 There are many variants of the service provider framework pattern. For example, the service access API can return a richer service interface to clients than the one furnished by providers. This is the Bridge pattern [Gamma95]. Dependency injection frameworks (Item 5) can be viewed as powerful service providers. Since Java 6, the platform includes a general-purpose service provider framework, java.util.ServiceLoader, so you needn’t, and generally shouldn’t, write your own (Item 59). JDBC doesn’t use ServiceLoader, as the former predates（vt.先于） the latter.
 
@@ -167,3 +167,7 @@ List<Complaint> litany = Collections.list(legacyLitany);
 In summary, static factory methods and public constructors both have their uses, and it pays to understand their relative merits. Often static factories are preferable, so avoid the reflex to provide public constructors without first considering static factories.
 
 总之，静态工厂方法和公共构造器都有各自的用途，理解它们的相对优点是值得的。通常静态工厂更可取，因此避免在没有考虑静态工厂的情况下提供公共构造函数。
+
+---
+**[Back to contents of the chapter（返回章节目录）](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Introduction.md)**
+- **Next Item（下一条目）：[Item 2: Consider a builder when faced with many constructor parameters（在面对多个构造函数参数时，请考虑构建器）](https://github.com/clxering/Effective-Java-3rd-edition-Chinese-English-bilingual/blob/master/Chapter-2/Chapter-2-Item-2-Consider-a-builder-when-faced-with-many-constructor-parameters.md)**