package Entity;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name="test")
public class user {
      private int id;
      private String name;
      @Id
      public int getId() {
            return id;
      }
      public void setId(int id) {
            this.id = id;
      }
      public String getName() {
            return name;
      }
      public void setName(String name) {
            this.name = name;
      }
}
@Entity：表明此类为entity bean
@Table(name="test")：与数据库中的表映射，并且表名为test。

package Entity;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.sql.DataSource;
/**
* Servlet implementation class TestEntityBean
*/
@WebServlet("/TestEntityBean")
public class TestEntityBean extends HttpServlet {
      private static final long serialVersionUID = 1L;
      /**
      * @see HttpServlet#HttpServlet()
      */
      public TestEntityBean() {
            super();
            // TODO Auto-generated constructor stub
      }
      /**
      * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
      */
      protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            // TODO Auto-generated method stub
            Context ctx;
            try {
                  ctx = new InitialContext();
                  DataSource ds = (DataSource) ctx.lookup("MySQLDS"); //通过JNDI找到数据源
                  Connection conn = ds.getConnection(); //建立连接
                  Statement stmt = null;
                  ResultSet rs = null;
                  stmt = conn.createStatement();
                  String sql = "select * from test;";
                  rs = stmt.executeQuery(sql); //执行SQL
                  while(rs.next()){
                        rs.getInt("id");
                        rs.getString("name"); //获取查询结果
                        System.out.println(rs.getString("name"));
                  }
            } catch (Exception e) {
                  // TODO Auto-generated catch block
                  e.printStackTrace();
            }
      }
      /**
      * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
      */
      protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            // TODO Auto-generated method stub
      }
}

该贴由koei123转至本版2015-6-2 8:56:16