Java类集（List接口-ArrayList）

//新的子类：ArrayList

package org.dml;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
public class ResultSetDemo01 {
public static final String DBDRIVER = "org.gjt.mm.mysql.Driver";
public static final String url = "jdbc:mysql://localhost:3306/mldn";
public static final String user = "root";
public static final String password = "root";
public static void main(String[] args) throws Exception{
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
String sql = "select id,name,password,age,sex from user";
Class.forName(DBDRIVER);
conn = DriverManager.getConnection(url,user,password);
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
while(rs.next()){
int id = rs.getInt("id");
String name = rs.getString("name");
String password = rs.getString("password");
int age = rs.getInt("age");
String sex = rs.getString("sex");
System.out.print("编号："+id+"；");
System.out.print("姓名："+name+"；");
System.out.print("密码："+password+"；");
System.out.print("年龄："+age+"；");
System.out.println("性别："+sex+"；");
System.out.println("------------------");
}
rs.close();
stmt.close();
conn.close();
}

}

package org.list;


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


public class ArrayListDemo02 {
public static void main(String[] args) {
List<String> allList = new ArrayList<String>();
allList.add("Hello");
allList.add(0,"World");
allList.add("chenfeipeng");
allList.add("www.hut.edu.cn");
System.out.println(allList);
allList.remove(0);
System.out.println(allList);
allList.remove("Hello");
System.out.println(allList);
allList.removeAll(allList);
System.out.println(allList);
}
}

package org.list;


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


public class ArrayListDemo03 {
public static void main(String[] args) {
List<String> allList = new ArrayList<String>();
allList.add("Hello");
allList.add("Hello");
allList.add(0,"World");
allList.add("chenfeipeng");
allList.add("www.hut.edu.cn");
System.out.println(allList);
System.out.println("由前向后输出：");
for(int i = 0;i<allList.size();i++){
System.out.print(allList.get(i)+"、");
}
System.out.println("\n由后向前输出：");
for(int i = allList.size()-1;i>=0;i--){
System.out.print(allList.get(i)+"、");
}
}
}

package org.list;


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


public class ArrayListDemo04 {
public static void main(String[] args) {
List<String> allList = new ArrayList<String>();
allList.add("Hello");
allList.add(0,"World");
allList.add("chenfeipeng");
allList.add("www.hut.edu.cn");
System.out.println(allList);
String str[] = allList.toArray(new String[]{});
System.out.println("指定数组类型：");
for(int i = 0;i<str.length;i++){
System.out.print(str[i]+"、");
}
System.out.println("\n返回对象数组：");
Object obj[] = allList.toArray();
for(int i = 0;i<obj.length;i++){
String temp = (String) obj[i];
System.out.print(temp+"、");
}
}
}

package org.list;


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


public class ArrayListDemo05 {
public static void main(String[] args) {
List<String> allList = new ArrayList<String>();
System.out.println("集合操作前是否为空？"+allList.isEmpty());
allList.add("Hello");
allList.add(0,"World");
allList.add("MLDN");
allList.add("www.hut.edu.cn");
System.out.println(allList);
System.out.println(allList.contains("Hello")?
"\"Hello\"字符串存在！":"\"Hello\"字符串不存在！");
List<String> allSub = allList.subList(3, 4);
System.out.print("集合截取：");
for(int i = 0;i<allSub.size();i++){
System.out.print(allList.get(i)+"、");
}
System.out.println("");
System.out.println("MLDN字符串的位置："+allList.indexOf("MLDN"));
System.out.println("集合操作后是否为空？"+allList.isEmpty());
}
}