package com_01_testfan_02_basic;import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;public class Day02_03_数据库取数据01 {public static void main(String[] args) {//找一个工具去连接数据库Connection conn = null;Statement statement = null;try {Class.forName("com.mysql.jdbc.Driver");//连接数据库conn = DriverManager.getConnection("jdbc:mysql://118.24.13.38:3308/test?characterEncoding=utf8&useSSL=false", "zhangsan", "123123");//准备sqlString  sql= "select * from t_user_test";//创建执行sql对象statement = conn.createStatement();//执行sql, 获取返回结果集合ResultSet  set=statement.executeQuery(sql);while (set.next()) {System.out.println(set.getString("uid")+" "+set.getString("loginname")+" "+set.getString("loginpass"));}} catch (Exception e) {e.printStackTrace();}finally {//数据库关闭try {conn.close();statement.close();} catch (SQLException e) {e.printStackTrace();}}}}

package com_01_testfan_02_basic;import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;public class Day02_04_数据库取数据02 {public static void main(String[] args) {List<DbUser> list = getAllDbUserTest();System.out.println(list.size());for (DbUser dbUser : list) {System.out.println(dbUser);}}public static List<DbUser> getAllDbUserTest(){Connection conn = null;Statement statement = null;List<DbUser> list =null;try {//找一个工具去连接数据库Class.forName("com.mysql.jdbc.Driver");//连接数据库conn = DriverManager.getConnection("jdbc:mysql://118.24.13.38:3308/test?characterEncoding=utf8&useSSL=false", "zhangsan", "123123");//准备sqlString  sql= "select * from t_user_test";//创建执行sql对象statement = conn.createStatement();//执行sql, 获取返回结果集合ResultSet  set=statement.executeQuery(sql);list = new ArrayList<DbUser>();while (set.next()) {DbUser user = new DbUser();user.setUid(set.getString("uid"));user.setLoginname(set.getString("loginname"));user.setLoginpass(set.getString("loginpass"));list.add(user);//System.out.println(set.getString("uid")+" "+set.getString("loginname")+" "+set.getString("loginpass"));
            }} catch (Exception e) {e.printStackTrace();}finally {//数据库关闭try {conn.close();statement.close();} catch (SQLException e) {e.printStackTrace();}}return list;}}

package com_01_testfan_02_basic;//数据库模拟对象
public class DbUser {private String uid;private String loginname;private String loginpass;public String getUid() {return uid;}public void setUid(String uid) {this.uid = uid;}public String getLoginname() {return loginname;}public void setLoginname(String loginname) {this.loginname = loginname;}public String getLoginpass() {return loginpass;}public void setLoginpass(String loginpass) {this.loginpass = loginpass;}@Overridepublic String toString() {return "DbUser [uid=" + uid + ", loginname=" + loginname + ", loginpass=" + loginpass + "]";}}