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
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 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(); } }
