1、import java.io.IOException;import java.io.PrintWriter;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.SQLException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class DeleteEmpServlet extends HttpServlet{ @Override
2、protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //解决中文乱码问题 request.setCharacterEncoding("utf-8"); response.setContentType("text/html;charset=utf-8"); //连接数据库 Connection con=null; String sql=null;
3、 PreparedStatement pstm=null; int id=Integer.parseInt(request.getParameter("id")); try {数据库的链接，DBUtil是之前建立的链接数据库的类，这里直接使用con=DBUtil.getConnection();使用PreparedStatement可以预编译sql语言，减少频繁的访问数据库，使性能降低
4、sql="delete from t_emp where id=?";pstm=con.prepareStatement(sql);pstm.setInt(1, id);pstm.executeUpdate();//重定向response.sendRedirect("listEmp");} catch (SQLException e) {System.out.println("连接异常");}finally {DBUtil.closeConnection(con);} }}
5、public class DBUt坡纠课柩il { private static String driver; privat髫潋啜缅e static String url; private static String username; private static String password; private static String initialSize; private static String maxActive; private static String maxIdle; private static String minIdle; private static String maxWait; private static BasicDataSource dataSource=null; private static Properties db=null; public static void init(){ db=new Properties(); try { db.load(DBUtil.class.getClassLoader().getResourceAsStream("db.properties")); driver=db.getProperty("driver"); url=db.getProperty("url"); username=db.getProperty("username"); password=db.getProperty("password"); initialSize=db.getProperty("initialSize"); maxActive=db.getProperty("maxActive"); maxIdle=db.getProperty("maxIdle"); minIdle=db.getProperty("minIdle"); maxActive=db.getProperty("maxWait"); //通过DataSource加载相关参数值 dataSource=new BasicDataSource(); dataSource.setDriverClassName(driver); dataSource.setUrl(url); dataSource.setUsername(username); dataSource.setPassword(password); if (initialSize!=null) {dataSource.setInitialSize(Integer.parseInt(initialSize));} if (maxActive!=null) {dataSource.setMaxActive(Integer.parseInt(maxActive));} if (maxIdle!=null) {dataSource.setMaxIdle(Integer.parseInt(maxIdle));} if (minIdle!=null) {dataSource.setMinIdle(Integer.parseInt(minIdle));} if (maxWait!=null) {dataSource.setMaxWait(Integer.parseInt(maxWait));} } catch (IOException e) {System.out.println("读取文件失败");throw new RuntimeException(e);}}
6、 //建立连接数据库的方法 public static Conne罕铞泱殳ction getConnection烫喇霰嘴() throws SQLException{ if (dataSource==null) {init();} Connection con=null; if (dataSource!=null) {con=dataSource.getConnection();}return con; } //关闭数据库 public static void closeConnection(Connection con){ try {con.close();} catch (SQLException e) {System.out.println("关闭连接失败");} }}DBUtil文件，这是一个静态类，我们可以在需要使用的时候直接调用里面的方法，
