• commons中 CollectionsUtils的一些功能


    package haohaoxuexi;
    /**
    * 函数式编程Closure 闭包封装业务功能
    * 1. Closure
    * CollectionUtils.forAllDo(容器,功能类对象)
    *
    * 2. IfClosure
    * IfClosure.ifClosure(断言,功能1,功能2)
    * CollectionUtils.forAllDo(容器,功能类对象)
    *
    * 3. WhileClosure
    * WhileClosure.whileClosure(断言,功能,标识符)
    * CollectionUtils.forAllDo(容器,功能类对象)
    *
    * 4. ChainedClosure
    * ChainedClosure.chainedClosure(功能列表)
    * CollectionUtils.forAllDo(容器,功能类对象)
    *
    */

    import java.util.ArrayList;
    import java.util.Iterator;
    import java.util.List;

    import org.apache.commons.collections4.Closure;
    import org.apache.commons.collections4.CollectionUtils;
    import org.apache.commons.collections4.Predicate;
    import org.apache.commons.collections4.functors.ChainedClosure;
    import org.apache.commons.collections4.functors.IfClosure;
    import org.apache.commons.collections4.functors.WhileClosure;

    public class lianxi33 {
    public static void main(String[] args) {

    basic();
    System.out.println("+++++++++++++++++++++++++++");
    isClosure();
    System.out.println("+++++++++++++++++++++++++++");
    whileClosure();
    System.out.println("++++++++++++++++++++++++++++");
    chainClousure();

    }
    public static void basic(){
    //定义一个容器,放入内容
    List<lianxi31> emList=new ArrayList<lianxi31>();
    emList.add(new lianxi31("BJSXT",20000));
    emList.add(new lianxi31("BJasdT",200000));
    emList.add(new lianxi31("BJsd",2000));

    //新建一个closure对象,规定出closure格式
    Closure<lianxi31> colsClosure=new Closure<lianxi31>() {
    public void execute(lianxi31 emp){
    emp.setSalary(emp.getSalary()*1.2);
    }};
    //利用工具类,实现对容器中内容的集体控制
    CollectionUtils.forAllDo(emList, colsClosure);
    //利用迭代器进行遍历输出
    Iterator<lianxi31> emIterator=emList.iterator();
    while (emIterator.hasNext()) {
    System.out.println(emIterator.next());
    }

    }
    /**
    * 二选一 如果打折商品,进行9折;否则满百减20
    */
    public static void isClosure(){
    //定义容器放入内容
    List<lianxi34> emList=new ArrayList<lianxi34>();
    emList.add(new lianxi34("asdasd",120,true));
    emList.add(new lianxi34("asd",100,false));
    emList.add(new lianxi34("aasd",10,false));
    //定义closure
    Closure<lianxi34> subClosure=new Closure<lianxi34>() {
    public void execute(lianxi34 goods){
    goods.setPrice(goods.getPrice()*1.2);
    }
    };
    //满百减20
    Closure<lianxi34> subtract=new Closure<lianxi34>() {
    public void execute(lianxi34 goods){
    if (goods.getPrice()>=100) {
    goods.setPrice(goods.getPrice()-20);
    }
    }
    };
    //打九折
    Closure<lianxi34> discount=new Closure<lianxi34>() {
    public void execute(lianxi34 goods){
    if (goods.getDiscount()) {
    goods.setPrice(goods.getPrice()*0.9);
    }
    }
    };
    //判断
    Predicate<lianxi34> preClosure=new Predicate<lianxi34>() {
    @Override
    public boolean evaluate(lianxi34 goods) {
    return goods.getDiscount();
    }
    };
    //利用ifclosure实现对容器的操作定义
    Closure<lianxi34> ifClo=IfClosure.ifClosure(preClosure, discount,subtract);
    //执行操作
    CollectionUtils.forAllDo(emList, ifClo);
    //利用迭代器遍历输出
    Iterator<lianxi34> emIterator=emList.iterator();
    while (emIterator.hasNext()) {
    System.out.println(emIterator.next());;
    }
    }

    /**
    * 将工资不断上涨知道到达全部10000以上
    */
    public static void whileClosure()
    {
    //数据
    List<lianxi31> empList = new ArrayList<>();
    empList.add(new lianxi31("周杰伦",20000));
    empList.add(new lianxi31("范冰冰",30000));
    empList.add(new lianxi31("黄晓明",5000));

    //业务功能 每次上涨0.2
    Closure<lianxi31> cols = new Closure<lianxi31>()
    {
    @Override
    public void execute(lianxi31 emp) {
    emp.setSalary(emp.getSalary()*1.2);
    }

    };

    //判断
    Predicate<lianxi31> empPre = new Predicate<lianxi31>() {
    @Override
    public boolean evaluate(lianxi31 emp) {
    return emp.getSalary()<10000;
    }
    };

    //false 表示while结构先判断后执行
    //true 表示do..while先执行后判断
    Closure<lianxi31> whileCols = WhileClosure.whileClosure(empPre,cols,false);


    //工具类
    CollectionUtils.forAllDo(empList, whileCols);

    //操作后的数据
    Iterator<lianxi31> empIt = empList.iterator();
    while(empIt.hasNext())
    {
    System.out.println(empIt.next());
    }
    }
    /**
    *折上减 如果打折商品,先进行9折,如果还满百,再减20
    */
    public static void chainClousure()
    {
    List<lianxi34> goodsList = new ArrayList<>();
    goodsList.add(new lianxi34("Android视频",120,true));
    goodsList.add(new lianxi34("javaee视频",110,false));
    goodsList.add(new lianxi34("Spack视频",80,false));

    //满百减20
    Closure<lianxi34> subtract = new Closure<lianxi34>() {
    @Override
    public void execute(lianxi34 input) {
    if(input.getPrice()>=100){
    input.setPrice(input.getPrice()-20);
    }
    }
    };

    //打折
    Closure<lianxi34> discount = new Closure<lianxi34>() {
    @Override
    public void execute(lianxi34 input) {
    if(input.getDiscount()){
    input.setPrice(input.getPrice()*0.9);
    }
    }
    };

    //链式操作
    Closure<lianxi34> chinaClo = ChainedClosure.chainedClosure(discount,subtract);

    //关联
    CollectionUtils.forAllDo(goodsList,chinaClo);

    //查看操作后的数据
    for(lianxi34 temp:goodsList)
    {
    System.out.println(temp);
    }
    }
    }

    public class lianxi31 {
    private String name;
    private double salary;

    public lianxi31() {
    }

    public String getName() {
    return name;
    }

    public void setName(String name) {
    this.name = name;
    }

    public double getSalary() {
    return salary;
    }

    public void setSalary(double salary) {
    this.salary = salary;
    }

    public lianxi31(String name, double salary) {
    super();
    this.name = name;
    this.salary = salary;
    }
    @Override
    public String toString() {
    return "码农:"+this.name+"工资"+this.salary;
    }
    }

    public class lianxi34 {
    private String name;
    private double price;
    private boolean discount;
    public lianxi34() {
    // TODO Auto-generated constructor stub
    }
    public lianxi34(String name, double price, boolean discount) {
    super();
    this.name = name;
    this.price = price;
    this.discount = discount;
    }
    public String getName() {
    return name;
    }
    public void setName(String name) {
    this.name = name;
    }
    public double getPrice() {
    return price;
    }
    public void setPrice(double price) {
    this.price = price;
    }
    public boolean getDiscount() {
    return discount;
    }
    public void setDiscount(Boolean discount) {
    this.discount = discount;
    }
    @Override
    public String toString() {
    return "商品:"+this.name+"价格:"+this.price+"是否打折:"+this.discount;
    }

    }

    guava的jar包导入之后没法使用,再网上找了很久的解决方法,还是没有解决,所以找了commons的jar包,以上是其中的一些功能,可以用于对容器内的元素进行操作

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  • 原文地址:https://www.cnblogs.com/zx931880423/p/6819068.html
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