数组与list的转换

如果想要把一个List转换为array数组，需要用其toArray方法，如：Company[] companies = (Company[]) companyList.toArray(new Company[companyList.size()]);

    如果想要把一个array数组转换为List，需要用到java.util.ArrayList类的asList方法，如：ArrayList companyList2 = new ArrayList( Arrays.asList(companies) );

完整的例子如下：

1. 先定义一个java bean: Company.java

package com.infosys.test;

public class Company {

private String comapnyInfo = null;

public String getComapnyInfo() {
  return comapnyInfo;
}

public void setComapnyInfo(String comapnyInfo) {
  this.comapnyInfo = comapnyInfo;
}
}
2. 定义Tester类，用Company的数组进行转化：

package com.infosys.test;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;

public class Tester {

/**
  * @param args
  */
public static void main(String[] args) {
  //lossArray = (Loss[]) lossList.toArray(new Loss[lossList.size()]);
  Company company1 = new Company();
  company1.setComapnyInfo("i am company 1");
  Company company2 = new Company();
  company2.setComapnyInfo("i am company 2");
  Company company3 = new Company();
  company3.setComapnyInfo("i am company 3");
  ArrayList companyList = new ArrayList();
  companyList.add(company1);
  companyList.add(company2);
  companyList.add(company3);
 
  // Convert the list into array
  Company[] companies = (Company[]) companyList.toArray(new Company[companyList.size()]);
  System.out.println("Array:");
  for (int length = 0; length < companies.length; length++) {
   System.out.println( companies[length].getComapnyInfo() );
  }
 
  // Convert the array into list
  ArrayList companyList2 = new ArrayList( Arrays.asList(companies) );
  System.out.println("List:");
  Iterator companyIterator = companyList2.iterator();
  while (companyIterator.hasNext()) {
   Company company = (Company) companyIterator.next();
   System.out.println( company.getComapnyInfo() );
  }
}

}


3. 运行Tester类的main方法后，控制台输出如下信息：

Array:
i am company 1
i am company 2
i am company 3
List:
i am company 1
i am company 2
i am company 3