Java实现获得MySQL数据库中所有表的记录总数可行方法
更新时间:2013年06月14日 15:58:13 作者:
可以通过SELECT COUNT(*) FROM table_name查询某个表中有多少条记录。本文给出两种可行的Java程序查询所有别的记录方法,感兴趣朋友可以了解下
在MySQL中,可以通过SELECT COUNT(*) FROM table_name查询某个表中有多少条记录。如果想知道某个数据库中所有别的记录总数应该怎么做呢?本文给出两种可行的Java程序,解决该问题。
1. 首先确定数据库中有多少个表,然后对每个表执行SELECT COUNT(*) FROM table_name
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
public class Test {
private static String driver = "com.mysql.jdbc.Driver";
private static String url = "jdbc:mysql://127.0.0.1/";
private static String db = "test";
private static String user = "root";
private static String pass = "test";
static Connection conn = null;
static Statement statement = null;
static PreparedStatement ps = null;
static ResultSet rs = null;
static List<String> tables = new ArrayList<String>();
public static void startMySQLConn() {
try {
Class.forName(driver).newInstance();
conn = DriverManager.getConnection(url+db, user, pass);
if (!conn.isClosed()) {
System.out.println("Succeeded connecting to MySQL!");
}
statement = conn.createStatement();
} catch (Exception e) {
e.printStackTrace();
}
}
public static void closeMySQLConn() {
if(conn != null){
try {
conn.close();
System.out.println("Database connection terminated!");
} catch (SQLException e) {
e.printStackTrace();
}
}
}
public static void getTables() {
String sql = "show tables;";
try {
ps = conn.prepareStatement(sql);
rs = ps.executeQuery();
while (rs.next()) {
tables.add(rs.getString(1));
}
} catch (Exception e) {
e.printStackTrace();
}
}
public static long getDbSum() {
long sum = 0;
String sql = "select count(*) from ";
try {
for(String tblName: tables) {
ps = conn.prepareStatement(sql + tblName + ";");
rs = ps.executeQuery();
while (rs.next()) {
sum += rs.getInt(1);
}
}
} catch (Exception e) {
e.printStackTrace();
}
return sum;
}
public static void main(String[] args) {
startMySQLConn();
getTables();
System.out.println(getDbSum());
closeMySQLConn();
}
}
2. 借助information_schema库的tables表
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
public class Test {
private static String driver = "com.mysql.jdbc.Driver";
private static String url = "jdbc:mysql://127.0.0.1/";
private static String db = "test";
private static String user = "root";
private static String pass = "test";
static Connection conn = null;
static Statement statement = null;
static PreparedStatement ps = null;
static ResultSet rs = null;
public static void startMySQLConn() {
try {
Class.forName(driver).newInstance();
conn = DriverManager.getConnection(url+db, user, pass);
if (!conn.isClosed()) {
System.out.println("Succeeded connecting to MySQL!");
}
statement = conn.createStatement();
} catch (Exception e) {
e.printStackTrace();
}
}
public static void closeMySQLConn() {
if(conn != null){
try {
conn.close();
System.out.println("Database connection terminated!");
} catch (SQLException e) {
e.printStackTrace();
}
}
}
public static void useDB() {
String sql = "use information_schema;";
try {
ps = conn.prepareStatement(sql);
rs = ps.executeQuery();
} catch (Exception e) {
e.printStackTrace();
}
}
public static long getDbSum() {
long sum = 0;
String sql = "select table_name,table_rows from tables where TABLE_SCHEMA = '" +
db + "' order by table_rows desc;";
//System.out.println(sql);
try {
ps = conn.prepareStatement(sql);
rs = ps.executeQuery();
while (rs.next()) {
sum += rs.getInt(2);
}
} catch (Exception e) {
e.printStackTrace();
}
return sum;
}
public static void main(String[] args) {
startMySQLConn();
useDB();
System.out.println(getDbSum());
closeMySQLConn();
}
}
1. 首先确定数据库中有多少个表,然后对每个表执行SELECT COUNT(*) FROM table_name
复制代码 代码如下:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
public class Test {
private static String driver = "com.mysql.jdbc.Driver";
private static String url = "jdbc:mysql://127.0.0.1/";
private static String db = "test";
private static String user = "root";
private static String pass = "test";
static Connection conn = null;
static Statement statement = null;
static PreparedStatement ps = null;
static ResultSet rs = null;
static List<String> tables = new ArrayList<String>();
public static void startMySQLConn() {
try {
Class.forName(driver).newInstance();
conn = DriverManager.getConnection(url+db, user, pass);
if (!conn.isClosed()) {
System.out.println("Succeeded connecting to MySQL!");
}
statement = conn.createStatement();
} catch (Exception e) {
e.printStackTrace();
}
}
public static void closeMySQLConn() {
if(conn != null){
try {
conn.close();
System.out.println("Database connection terminated!");
} catch (SQLException e) {
e.printStackTrace();
}
}
}
public static void getTables() {
String sql = "show tables;";
try {
ps = conn.prepareStatement(sql);
rs = ps.executeQuery();
while (rs.next()) {
tables.add(rs.getString(1));
}
} catch (Exception e) {
e.printStackTrace();
}
}
public static long getDbSum() {
long sum = 0;
String sql = "select count(*) from ";
try {
for(String tblName: tables) {
ps = conn.prepareStatement(sql + tblName + ";");
rs = ps.executeQuery();
while (rs.next()) {
sum += rs.getInt(1);
}
}
} catch (Exception e) {
e.printStackTrace();
}
return sum;
}
public static void main(String[] args) {
startMySQLConn();
getTables();
System.out.println(getDbSum());
closeMySQLConn();
}
}
2. 借助information_schema库的tables表
复制代码 代码如下:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
public class Test {
private static String driver = "com.mysql.jdbc.Driver";
private static String url = "jdbc:mysql://127.0.0.1/";
private static String db = "test";
private static String user = "root";
private static String pass = "test";
static Connection conn = null;
static Statement statement = null;
static PreparedStatement ps = null;
static ResultSet rs = null;
public static void startMySQLConn() {
try {
Class.forName(driver).newInstance();
conn = DriverManager.getConnection(url+db, user, pass);
if (!conn.isClosed()) {
System.out.println("Succeeded connecting to MySQL!");
}
statement = conn.createStatement();
} catch (Exception e) {
e.printStackTrace();
}
}
public static void closeMySQLConn() {
if(conn != null){
try {
conn.close();
System.out.println("Database connection terminated!");
} catch (SQLException e) {
e.printStackTrace();
}
}
}
public static void useDB() {
String sql = "use information_schema;";
try {
ps = conn.prepareStatement(sql);
rs = ps.executeQuery();
} catch (Exception e) {
e.printStackTrace();
}
}
public static long getDbSum() {
long sum = 0;
String sql = "select table_name,table_rows from tables where TABLE_SCHEMA = '" +
db + "' order by table_rows desc;";
//System.out.println(sql);
try {
ps = conn.prepareStatement(sql);
rs = ps.executeQuery();
while (rs.next()) {
sum += rs.getInt(2);
}
} catch (Exception e) {
e.printStackTrace();
}
return sum;
}
public static void main(String[] args) {
startMySQLConn();
useDB();
System.out.println(getDbSum());
closeMySQLConn();
}
}
相关文章
MySQL修改innodb_data_file_path参数的一些注意事项
这篇文章主要给大家介绍了关于MySQL修改innodb_data_file_path参数的一些注意事项,文中通过示例代码介绍的非常详细,对大家学习或者使用MySQL具有一定的参考学习价值,需要的朋友们下面来一起学习学习吧2019-04-04
如何通过sql查找所有父节点和所有子节点(以mysql为例)
这篇文章主要给大家介绍了关于如何通过sql查找所有父节点和所有子节点,本文以mysql为例,项目中遇到一个需求,要求查处菜单节点的所有节点,这里给大家总结下,需要的朋友可以参考下2023-08-08
mysql自增navicat_navicat如何设置主键自增
通过Navicat设置MySQL表的主键自增,步骤包括:打开Navicat连接数据库,选择表并设计,右击id字段设置为主键,然后勾选自动递增功能,这样每次插入新记录时,id字段都会自动递增2025-01-01
mysql5.6 解析JSON字符串方式(支持复杂的嵌套格式)
这篇文章主要介绍了mysql5.6 解析JSON字符串方式(支持复杂的嵌套格式),具有很好的参考价值,希望对大家有所帮助。如有错误或未考虑完全的地方,望不吝赐教2022-07-07


最新评论