Java当中数据库访问类：DB类
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DB类是项目用来连接数据库的辅助类：
封装和数据库的连接。
主要是和数据库连接的相关信息：
1.找到驱动程序
Class.forName("com.mysql.jdbc.Driver");
2.连接字符串
DriverManager.getConnection("jdbc:mysql://localhost/shopping?user=roo t&password=root");
3.PreparedStatement
4.Statement
5. Result
package com.bjsxt.shopping.util;
import java.sql.*;
publicclass DB {
publicstatic Connection getConn() {
Connection conn = null;
try {
Class.forName("com.mysql.jdbc.Driver");
conn =
DriverManager.getConnection("jdbc:mysql://localhost/shopping?user=roo t&password=root");
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
publicstatic PreparedStatement prepare(Connection conn, String sql) {
PreparedStatementpstmt = null;
try {
if(conn != null) {
pstmt = conn.prepareStatement(sql);
}
} catch (SQLException e) {
e.printStackTrace();
}
return pstmt;
}
publicstatic PreparedStatement prepare(Connection conn, String sql, int autoGenereatedKeys) {
PreparedStatementpstmt = null;
try {
if(conn != null) {
pstmt = conn.prepareStatement(sql, autoGenereatedKeys);
}
} catch (SQLException e) {
e.printStackTrace();
}
return pstmt;
}
publicstatic Statement getStatement(Connection conn) {
Statement stmt = null;
try {
if(conn != null) {
stmt = conn.createStatement();
}
} catch (SQLException e) {
e.printStackTrace();
}
return stmt;
}
/*
public static ResultSetgetResultSet(Connection conn, String sql) { Statement stmt = getStatement(conn);
ResultSetrs = getResultSet(stmt, sql);
close(stmt);
returnrs;
}
*/
publicstatic ResultSetgetResultSet(Statement stmt, String sql) { ResultSetrs = null;
try {
if(stmt != null) {
rs = stmt.executeQuery(sql);
}
} catch (SQLException e) {
e.printStackTrace();
}
return rs;
}
publicstaticvoid executeUpdate(Statement stmt, String sql) { try {
if(stmt != null) {
stmt.executeUpdate(sql);
}
} catch (SQLException e) {
e.printStackTrace();
}
}
publicstaticvoid close(Connection conn) {
try {
if(conn != null) {
conn.close();
conn = null;
}
} catch (SQLException e) {
e.printStackTrace();
}
}
publicstaticvoid close(Statement stmt) {
try {
if(stmt != null) {
stmt.close();
stmt = null;
}
} catch (SQLException e) {
e.printStackTrace();
}
}
publicstaticvoid close(ResultSetrs) {
try {
if(rs != null) {
rs.close();