Java Collections replaceAll()

replaceAll() 用于将列表中一个指定值的所有出现都替换为另一个指定值。

1 语法

public static <T> boolean replaceAll(List<T> list, T oldVal, T newVal)    

2 参数

list：要进行替换的列表。

oldVal：将被替换的旧值。

newVal：要替换oldVal的新值。

3 返回值

如果列表包含一个或多个元素，例如 (oldVal==null ? e==null : oldVal.equals(e))，则replaceAll() 方法返回true。

4 Collections replaceAll()示例1

package com.yiidian;

/**
 * 一点教程网： http://www.yiidian.com
 */
/**
 * Java Collections.replaceAll的例子
 */
import java.util.*;

public class Demo {

    public static void main(String[] args) {
        //Create vector and add element in this vector
        Vector<String> vector = new Vector<String>();
        vector.add("Java");
        vector.add("Yiidian");
        vector.add("SM1234");
        vector.add("Java");
        System.out.println("Initial values are :"+vector);
        //Replace 'Java' with 'JavaTpont'
        Collections.replaceAll(vector, "Java", "Yiidian");
        System.out.println("Value after replace :"+ vector);
    }
}

输出结果为：

Initial values are :[Java, Yiidian, SM1234, Java]
Value after replace :[Yiidian, Yiidian, SM1234, Yiidian]

5 Collections replaceAll()示例2

package com.yiidian;

/**
 * 一点教程网： http://www.yiidian.com
 */
/**
 * Java Collections.replaceAll的例子
 */
import java.util.*;

public class Demo {

    public static void main(String[] args) {
        //Create an list of String
        List<String> list = Arrays.asList("one", "two", "one");
        System.out.println("Original List:- "+list);
        boolean b = Collections.replaceAll(list, "one", "three");
        System.out.println("Boolean: "+b);
        System.out.println("Value after replace:- "+list);
    }
}

输出结果为：

Original List:- [one, two, one]
Boolean: true
Value after replace:- [three, two, three]

6 Collections replaceAll()示例3

package com.yiidian;

/**
 * 一点教程网： http://www.yiidian.com
 */
/**
 * Java Collections.replaceAll的例子
 */
import java.util.*;

public class Demo {

    public static void main(String[] args) {
        //Create an list of integers
        List<String> list = Arrays.asList("10", "20", "10", "40", "50", "10");
        System.out.println("Original List: " +list);
        boolean b = Collections.replaceAll(list, "10", "400");
        System.out.println("Boolean: "+b);
        System.out.println("Value after Replace: " +list);
    }
}

输出结果为：

Original List: [10, 20, 10, 40, 50, 10]
Boolean: true
Value after Replace: [400, 20, 400, 40, 50, 400]