Java+JSP+Oracle+Ajax前台显示数据库数据

迈不过友情╰ 2022-06-18 05:29 232阅读 0赞

## Java+JSP+Oracle+Ajax前台显示数据库数据 ##

在这个例子中，我们将使用Java查询Oracle数据库里面的数据并在前台JSP页面显示。  
**一、准备**  
Java连接Oracle数据库请参考 Java连接Oracle数据库.note  
使用Ajax需要jQuery.js文件，下载：[http://www.jq22.com/jquery-info122][http_www.jq22.com_jquery-info122]  
必要的连接Oracle的jar包。  
所用数据库表数据：  
![这里写图片描述][SouthEast]  
**二、创建工程**  
工程的完整目录为：  
![这里写图片描述][SouthEast 1]

*  **JdbcUtils.java**
    
    JdbcUtils.java连接数据库

package com.cu.test;
    
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.SQLException;
    
    public class JdbcUtils { 
    
        private static final String driverUrl = "oracle.jdbc.driver.OracleDriver";
    
        private static final String url = "jdbc:oracle:thin:@59.71.244.71:1521:ORCL";
    
        private static final String username = "SXUSER";
    
        private static final String password = "1234";
    
        public static Connection getConnection(){
            Connection connection = null;
            try {
                Class.forName(driverUrl);
                connection = DriverManager.getConnection(url, username, password);
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            System.out.println("连接成功！");
            return connection;
        }
    }

*  **DataInfo.java**  
    DataInfo用来保存由数据库传来的数据

package com.cu.test;
    
    public class DataInfo {
        public int id,age;
        public String name,sex;
        public int getId() {
            return id;
        }
        public void setId(int id) {
            this.id = id;
        }
        public int getAge() {
            return age;
        }
        public void setAge(int age) {
            this.age = age;
        }
        public String getName() {
            return name;
        }
        public void setName(String name) {
            this.name = name;
        }
        public String getSex() {
            return sex;
        }
        public void setSex(String sex) {
            this.sex = sex;
        }
    }

*  **DataSets.java**  
    DataSets类获取数据库数据，返回存有数据的list

package com.cu.test;
    
    import java.sql.Connection;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.sql.Statement;
    import java.util.ArrayList;
    
    public class DataSets { 
        public static String sql="select * from ODBC_IMPORT t";
        public static Statement stmt = null;
        public static ResultSet res = null;
        public static Connection conn = null;
        public static ArrayList<DataInfo> list=new ArrayList<DataInfo>();
    
        public static ArrayList<DataInfo> getDataInfo(){
            try {
                conn=JdbcUtils.getConnection();
                stmt = conn.createStatement();
                res = stmt.executeQuery(sql);
                while(res.next())
                {
                    DataInfo data=new DataInfo();
                    data.setId(res.getInt("ID"));
                    data.setName(res.getString("NAME"));
                    data.setAge(res.getInt("AGE"));
                    data.setSex(res.getString("SEX"));
                    list.add(data);
                }
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return list;
    
        }
    
        //将list转成json样式的字符串
        public static String dataJson(ArrayList<DataInfo> list){
            String json="{\"people\":[";
            for (DataInfo dataInfo : list) {
                String line="{\"name\":\""+dataInfo.getName()+
                        "\",\"id\":"+dataInfo.getId()+","+
                        "\"age\":"+dataInfo.getAge()+","+
                        "\"sex\":"+dataInfo.getSex()+"},"+
                        "\r\n";
                json=json+line;
            }
            json=json.substring(0, json.length()-3);
            json=json+"]}";
            return json;
    
        }
    }

*  **DataServlet.java**  
    新建DataServlet类，用于将获得的数据传往前台JSP页面

package com.cu.test;
    
    import java.io.IOException;
    import java.io.PrintWriter;
    import java.util.ArrayList;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    public class DataServlet extends HttpServlet { 
        public void doGet(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException {
    
            doPost(request, response);
        }
        public void doPost(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException {
    
            request.setCharacterEncoding("utf-8"); 
            response.setContentType("text/html;charset=utf-8"); 
            response.setCharacterEncoding("utf-8"); 
    
            ArrayList<DataInfo> list=DataSets.getDataInfo();
            String json=DataSets.dataJson(list);
            PrintWriter out = response.getWriter();
            out.println(json);
            out.close();
        }
    }

*  **MyJsp.jsp**  
    前台JSP页面代码，点击按钮显示后台数据

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %>
    
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    <html>
      <head>
        <base href="<%=basePath%>">
    
        <title>My JSP 'MyJsp.jsp' starting page</title>
    
        <meta http-equiv="pragma" content="no-cache">
        <meta http-equiv="cache-control" content="no-cache">
        <meta http-equiv="expires" content="0">    
        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
        <meta http-equiv="description" content="This is my page">
        
        <script src="jquery-3.0.0.js" type="text/javascript"></script>
        <script type="text/javascript"> function myFunction(){ $.ajax({ type:"post", //传输方式为post，所以我们在servlet里面代码是写在doPost()函数中 url:"DataServlet", //这就是使用的servlet的url success:function(data){ document.getElementById("json").innerHTML=data; } }); } </script>
      </head>
    
      <body>
        <p id="json">数据</p><br>
        <button onclick="myFunction()">获取数据</button>
      </body>
    </html>

运行MyJsp.jsp的结果：  
![这里写图片描述][SouthEast 2]  
![这里写图片描述][SouthEast 3]

[http_www.jq22.com_jquery-info122]: http://www.jq22.com/jquery-info122
[SouthEast]: /images/20220618/0420116fe46f4907953057a3d6af49ec.png
[SouthEast 1]: /images/20220618/932d333128e34f2c870824210e2824cc.png
[SouthEast 2]: /images/20220618/25559298e29e40cb989d7f63a8c7621c.png
[SouthEast 3]: /images/20220618/355f820a54f54069808a848285699d36.png