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Java實現獲得MySQL數據庫中所有表的記錄總數可行方法
可以通過SELECT COUNT(*) FROM table_name查詢某個表中有多少條記錄。本文給出兩種可行的Java程序查詢所有別的記錄方法，感興趣朋友可以了解下
在MySQL中，可以通過SELECT COUNT(*) FROM table_name查詢某個表中有多少條記錄。如果想知道某個數據庫中所有別的記錄總數應該怎麼做呢？本文給出兩種可行的Java程序，解決該問題。
1. 首先確定數據庫中有多少個表，然後對每個表執行SELECT COUNT(*) FROM table_name
代碼如下：
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庫的tables表
複製代碼 代碼如下:
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();
}
}
最後更新：2017-04-03 14:54:20