JAVA程序经常看到一个函数中包含了十几个if-else的分支判断
比如 根据不同职位增加工资的例子
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public class Employee {
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private int salary = 10;
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public void addMoney(String str) {
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if ("初级JAVA程序员".equals(str)) {
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this.salary = salary + 30;
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} else if ("中级JAVA程序员".equals(str)) {
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this.salary = salary + 50;
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} else if ("高级JAVA程序员".equals(str)) {
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this.salary = salary + 80;
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} else if ("架构师".equals(str)) {
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this.salary = salary + 100;
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} else if ("数据库管理员".equals(str)) {
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this.salary = salary + 100;
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} else if ("项目经理".equals(str)) {
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this.salary = salary + 100;
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} else if ("菜鸟".equals(str)) {
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this.salary = salary + 10;
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}
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// ...
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System.out.println(this.salary);
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}
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public static void main(String[] args) {
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Employee e = new Employee();
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e.addMoney("菜鸟");
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}
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}
可以改写如下
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import java.util.HashMap;
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import java.util.Map;
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public class Employee {
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private int salary = 10;
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private interface IStrategy {
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int addMoney();
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};
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Map<String, IStrategy> strategy = new HashMap<String, IStrategy>();
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{
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strategy.put("初级JAVA程序员", new IStrategy() {
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@Override
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public int addMoney() {
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return 30;
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}
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});
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strategy.put("中级JAVA程序员", new IStrategy() {
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@Override
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public int addMoney() {
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return 50;
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}
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});
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strategy.put("高级JAVA程序员", new IStrategy() {
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@Override
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public int addMoney() {
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return 80;
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}
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});
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strategy.put("架构师", new IStrategy() {
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@Override
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public int addMoney() {
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return 100;
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}
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});
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strategy.put("数据库管理员", new IStrategy() {
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@Override
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public int addMoney() {
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return 100;
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}
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});
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strategy.put("项目经理", new IStrategy() {
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@Override
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public int addMoney() {
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return 100;
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}
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});
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strategy.put("菜鸟", new IStrategy() {
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@Override
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public int addMoney() {
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return 10;
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}
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});
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}
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public void addMoney(String str) {
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this.salary = salary + strategy.get(str).addMoney();
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System.out.println(this.salary);
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}
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public static void main(String[] args) {
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Employee e = new Employee();
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e.addMoney("菜鸟");
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}
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}
如果是复杂的项目,可以把匿名内部类改为普通类.
改写之后,无论新增或者删除逻辑,都非常的简单明了,并且逻辑的变更,限制在了一个较小的范围.
实现了高内聚,低耦合的设计思路.
参考:
http://raychase.iteye.com/blog/1814187
过多if-else分支的优化
原文：http://blog.itpub.net/29254281/viewspace-1409748/
