java读取数据库，操作相关数值
一、先准备好mysql的基本环境。
详细见https://blog.csdn.net/weixin_42575806/article/details/80941917
二、下载mysql-connector-java-8.0.11.jar的jira包放到项目lib目录下
下载地址https://dev.mysql.com/downloads/connector/j/
三、创建数据库表结构
DROP TABLE IF EXISTS `base_app_version`;
CREATE TABLE `base_app_version` (
`id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主键',
`version_id` varchar(50) DEFAULT '' COMMENT '版本号',
`type` int(2) DEFAULT '0' COMMENT '0:安卓，1：ISO',
`version_url` varchar(200) DEFAULT '' COMMENT '版本URL',
`city_code` varchar(6) DEFAULT '',
`create_time` varchar(14) DEFAULT '' COMMENT '创建时间',
`force_to_update` bit(1) DEFAULT b'0' COMMENT '是否强制更新',
`content_desc` varchar(800) NOT NULL COMMENT '更新内容描述',
`soft_type` int(2) DEFAULT '0' COMMENT '0:用户端，1：司机端',
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8 ROW_FORMAT=DYNAMIC COMMENT='app版本表';
-- ----------------------------
-- Records of base_app_version
-- ----------------------------
INSERT INTO `base_app_version` VALUES ('3', 'V1.0.0', '0', '', '420100', '2018 07 05 11 30 00', '\0', 'sdfsdfsdfsfdsdfsdf', '0');四、创建java工程
4.1 主入口 （text.java ）
package test0705;
public class text {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("I coming for test connet mysql!");
JdbcTest1.connetMysql();
}
}
4.2 创建表对应的类文件（BaseAppVersion.java）
package test0705;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
//CREATE TABLE `base_app_version` (
// `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主键',
// `version_id` varchar(50) DEFAULT '' COMMENT '版本号',
// `type` int(2) DEFAULT '0' COMMENT '0:安卓，1：ISO',
// `version_url` varchar(200) DEFAULT '' COMMENT '版本URL',
// `city_code` varchar(6) DEFAULT '',
// `create_time` varchar(14) DEFAULT '' COMMENT '创建时间',
// `force_to_update` bit(1) DEFAULT b'0' COMMENT '是否强制更新',
// `content_desc` varchar(800) NOT NULL COMMENT '更新内容描述',
// `soft_type` int(2) DEFAULT '0' COMMENT '0:用户端，1：司机端',
// PRIMARY KEY (`id`)
// ) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8 ROW_FORMAT=DYNAMIC COMMENT='app版本表';
public class BaseAppVersion {
private int id;
private String version_id;
private int type;
private String version_url;
private String city_code;
private String create_time;
private int force_to_update;
private String content_desc;
private int soft_type;
BaseAppVersion(int id,String version_id,int type,String version_url,String city_code,
String create_time,int force_to_update,String content_desc,int soft_type) {
this.id = id;
this.version_id = version_id;
this.type = type;
this.version_url = version_url;
this.city_code = city_code;
this.create_time = create_time;
this.force_to_update = force_to_update;
this.content_desc = content_desc;
this.soft_type = soft_type;
}
BaseAppVersion() {}
public int getId() {
return id;
}
public void setId(int newid) {
this.id = newid;
}
public String getVersionId() {
return version_id;
}
public void setVersionId(String newversion_id) {
this.version_id = newversion_id;
}
public int getType() {
return type;
}
public void setType(int newtype) {
this.type = newtype;
}
public String getversion_url() {
return version_url;
}
public void setversion_url(String newversion_url) {
this.version_url = newversion_url;
}
public String getcity_code() {
return city_code;
}
public void setcity_code(String newcity_code) {
this.city_code = newcity_code;
}
public String getcreate_time() {
return create_time;
}
public void setcreate_time(String newcreate_time) {
this.create_time = newcreate_time;
}
public int getforce_to_update() {
return force_to_update;
}
public void setforce_to_update(int newforce_to_update) {
this.force_to_update = newforce_to_update;
}
public String getcontent_desc() {
return content_desc;
}
public void setcontent_desc(String newcontent_desc) {
this.content_desc = newcontent_desc;
}
public int getsoft_type() {
return soft_type;
}
public void setsoft_type(int newsoft_type) {
this.soft_type = newsoft_type;
}
//读取数据库表结构值存在到当前类中
public static List SelectBaseAppVersionData(Statement stmt, String sqlstr) throws SQLException{
List list = new ArrayList();
ResultSet rs = stmt.executeQuery(sqlstr);//查询多个表
ResultSetMetaData md = rs.getMetaData();
int col = md.getColumnCount();
while(rs.next()){
BaseAppVersion bav = new BaseAppVersion();
bav.setId(rs.getInt("id"));
bav.setVersionId(rs.getString("version_id"));
bav.setType(rs.getInt("type"));
bav.setversion_url(rs.getString("version_url"));
bav.setcity_code(rs.getString("city_code"));
bav.setcreate_time(rs.getString("create_time"));
bav.setforce_to_update(rs.getInt("force_to_update"));
bav.setcontent_desc(rs.getString("content_desc"));
bav.setsoft_type(rs.getInt("soft_type"));
list.add(bav);
}
if( rs != null){
try{
rs.close();
} catch (SQLException e){
System.out.println("ResultSet 关闭时出现错误！");
e.printStackTrace();
}
}
return list;
}
//显示当前类查询值
public static void showBaseAppVersion(BaseAppVersion bav) {
System.out.println(" List for BaseAppVersion " + " id: "+ bav.getId()+ " version_id: "+ bav.getVersionId()
+ " type: "+ bav.getType() + " version_url: "+ bav.getversion_url() + " city_code: "+ bav.getcity_code()
+ " create_time: "+ bav.getcreate_time()+ " force_to_update: "+ bav.getforce_to_update()
+ " content_desc: "+ bav.getcontent_desc() + " soft_type: "+ bav.getsoft_type());
}
}
4.3 创建数据操作文件（JdbcTest1.java）package test0705;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.ResultSet;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class JdbcTest1 {
//获取当前时间，按照固定格式例如：yyyyMMddHHmmss
public static String getCurrentTime( String timeFormat){
LocalDateTime arrivalDate = LocalDateTime.now().withNano(0);
DateTimeFormatter format = DateTimeFormatter.ofPattern(timeFormat);
String nowTime = arrivalDate.toString().replaceAll("T", "");
nowTime = arrivalDate.format(format);
System.out.println("arrivalDate: " + arrivalDate + " nowTime: " + nowTime);
return nowTime;
}
//显示当前时间类型
public static void showTime(){
LocalDate today = LocalDate.now();
LocalTime time = LocalTime.now();
System.out.println("today: " + today + " time: " + time.withNano(0));
int year = today.getYear();
int month = today.getMonthValue();
int day = today.getDayOfMonth();
System.out.println("Year : "+ year + " Month :" + month + " day :" + day );
LocalTime newTime = time.plusHours(2); // adding two hours
System.out.println("Time after 2 hours : " + newTime);
}
//1.数据库删除
public static int DeleteData(Statement stmt, String sqlstr) throws SQLException{
int re = stmt.executeUpdate(sqlstr);
if(re != -1){
System.out.println(sqlstr + "数据库值删除成功！");
} else {
System.out.println(sqlstr + "数据库值删除失败！");
}
return re;
}
//2.数据库增加
public static int AddData(PreparedStatement ps) throws SQLException{
int re = ps.executeUpdate();//执行sql语句
if(re != -1){
System.out.println(ps.toString() + "数据库插入成功！");
} else {
System.out.println(ps.toString() + "数据库插入失败！");
}
return re;
}
//3.数据库更新
public static int UpdateData(Statement stmt, String sqlstr) throws SQLException{
int re = stmt.executeUpdate(sqlstr);
if(re != -1){
System.out.println(sqlstr + "数据库更新成功！");
} else {
System.out.println(sqlstr + "数据库更新失败！");
}
return re;
}
//4.数据库查找
public static int SelectData(Statement stmt, String sqlstr) throws SQLException{
ResultSet rs = stmt.executeQuery(sqlstr);//查询多个表
int col = rs.getMetaData().getColumnCount();
while(rs.next()){
for (int i = 1; i <= col; i++) {
System.out.print(rs.getString(i) + "\t");
}
System.out.println("\n==========================================================================================");
}
if( rs != null){
try{
rs.close();
} catch (SQLException e){
System.out.println("ResultSet 关闭时出现错误！");
e.printStackTrace();
}
}
return 1;
}
//不区分class类别进行数据库查找
public static List newSelectData(Statement stmt, String sqlstr) throws SQLException{
List list = new ArrayList();
ResultSet rs = stmt.executeQuery(sqlstr);//查询多个表
ResultSetMetaData md = rs.getMetaData();
int col = md.getColumnCount();
while(rs.next()){
Map rowData = new HashMap();
for (int i = 1; i <= col; i++) {
rowData.put(md.getColumnName(i),rs.getObject(i));
}
list.add(rowData);
}
if( rs != null){
try{
rs.close();
} catch (SQLException e){
System.out.println("ResultSet 关闭时出现错误！");
e.printStackTrace();
}
}
return list;
}
public static void connetMysql(){
Connection conn = null;// conn用于连接数据库
Statement stmt = null;// stmt用于发送sql语句到数据库并执行sql语句
String sqlstr = null;
String connectionString = "jdbc:mysql://10.1.254.180:3306/wptest?user=wp&password=123456&useUnicode=true&";
try{
// Class.forName("com.mysql.jdbc.Driver").newInstance(); 老版本数据1.8版本前的连接方式
Class.forName("com.mysql.cj.jdbc.Driver").newInstance();//新版本连接方式
System.out.println(connectionString);
conn = DriverManager.getConnection(connectionString);
System.out.println("connect success!");
stmt = conn.createStatement();
showTime();//just for test time and date
//1.数据库删除
int st = 0;
sqlstr = "DELETE FROM base_app_version WHERE soft_type = " + st +";";
DeleteData(stmt,sqlstr);
//2.数据库增加
sqlstr = "INSERT INTO `base_app_version` VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?);";
PreparedStatement ps = conn.prepareStatement(sqlstr);//创建一个Statement对象
ps.setInt(1,0);//id
ps.setString(2,"V1.0.1");//version_id
ps.setInt(3,0);//type
ps.setString(4,"");//version_url
ps.setString(5,"420101");//city_code
ps.setString(6, getCurrentTime("yyyyMMddHHmmss"));//create_time
ps.setInt(7,0);//force_to_update
ps.setString(8,"mytestinsert");//content_desc
ps.setInt(9,0);//soft_type
AddData(ps);
//3.数据库更新
sqlstr = "UPDATE base_app_version SET city_code = '420111' WHERE soft_type = " + st +";";
UpdateData(stmt, sqlstr);
//4.数据库查找
sqlstr = "Select * from base_app_version;";
SelectData(stmt,sqlstr);//查找数据库所有字段值
BaseAppVersion bav = new BaseAppVersion();
List baseAppVersionL = bav.SelectBaseAppVersionData(stmt,sqlstr);
for(int i=0; i