java 连接mysql数据库

//引用jar包 mysql-connector-java-5.1.18-bin.jar

import java.sql.*;

public class DB {

public static Connection getConn(){

Connection conn=null;

try{

Class.forName("com.mysql.jdbc.Driver");

conn=DriverManager.getConnection("jdbc:mysql://localhost/database_name?user=user_name&password=password_str");

}

catch (ClassNotFoundException e) {

e.printStackTrace();

}

catch (SQLException e) {

e.printStackTrace();

}

return conn;

}

public static Statement getStatement(Connection conn){

Statement stmt=null;

try{

if(conn!=null){

stmt=conn.createStatement();

}

}

catch (SQLException e) {

e.printStackTrace();

}

return stmt;

}

public static ResultSet getResultSet(Statement stmt,String sql) {

ResultSet rs=null;

try {

if(stmt!=null){

rs=stmt.executeQuery(sql);

}

} catch (SQLException e) {

e.printStackTrace();

}

return rs;

}

public static void closeConn(Connection conn) {

try{

if(conn!=null){

conn.close();

conn=null;

}

}

catch (SQLException e) {

e.printStackTrace();

}

}

public static void closeStmt(Statement stmt){

try{

if(stmt!=null){

stmt.close();

stmt=null;

}

}

catch (SQLException e) {

e.printStackTrace();

}

}

public static void closeRs(ResultSet rs){

try {

if(rs!=null){

rs.close();

rs=null;

}

} catch (SQLException e) {

e.printStackTrace();

}

}

}

/*调用时

Connection conn=DB.getConn();

Statement stmt=DB.getStatement(conn);

String sql="select * from table_name";

ResultSet rs=DB.getResultSet(stmt, sql);

try {

while(rs.next()){

System.out.println(rs.getString("column_name"));

}

} catch (SQLException e) {

e.printStackTrace();

}

finally{

DB.closeRs(rs);

DB.closeStmt(stmt);

DB.closeConn(conn);

}

*/