[Java知识库]struts2数据库连接显示数据

struts2连接oracle数据库并显示数据到页面

1. 建表
   create table cost2(
   id number(4) primary key,
   name varchar2(50),
   base_cost number(4,2),
   stauts char(1)
   );
   插入几行数据
   insert into cost2 values (1,‘本月流量消费’,10.0,1);
   insert into cost2 values (2,‘本月流量消费’,12.0,1);
   insert into cost2 values (3,‘本月流量消费’,9.0,0);
2. 把jar包加载到maven库
   打开cmd输入这行命令mvn install:install-file -DgroupId=com.oracle -DartifactId=ojdbc6 -Dversion=11.2.0.3.0 -Dpackaging=jar -Dfile=E:\tools\orac_\ojdbc6.jar（这路径以自己的为准）
   3.打开IDEA工具创建maven项目
   
   在pom.xml导入依赖

<dependency>
      <groupId>org.apache.struts</groupId>
      <artifactId>struts2-core</artifactId>
      <version>2.5.28</version>
    </dependency>
    <dependency>
      <groupId>com.oracle</groupId>
      <artifactId>ojdbc6</artifactId>
      <version>11.2.0.3.0</version>
    </dependency>

web.xml中配置过滤器

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Archetype Created Web Application</display-name>
    <filter>
      <filter-name>struts2</filter-name>
      <filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter</filter-class>
    </filter>
  <filter-mapping>
    <filter-name>struts2</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>

在resources文件下新建struts.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN" "http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
    <package name="ghh" namespace="/data" extends="struts-default">
        <action name="f1" class="Action.OAction" method="find">
            <result name="success">/info.jsp</result>
        </action>
    </package>
</struts>

在resources文件下新建jdbc.properties文件这里存放连接数据库的几个值

driver=oracle.jdbc.driver.OracleDriver
url=jdbc\:oracle\:thin\:@localhost\:1521\:XE
username=system
password=hfghf

4. 编写实现功能代码
   项目目录结构如下
   
   实体类Account

package pojo;

public class Account {
    int id;
    String name;
    Double base_cost;
    String stauts;

    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;
    }

    public Double getBase_cost() {
        return base_cost;
    }

    public void setBase_cost(Double base_cost) {
        this.base_cost = base_cost;
    }

    public String getStauts() {
        return stauts;
    }

    public void setStauts(String stauts) {
        this.stauts = stauts;
    }
}

工具类DBLink连接数据库的

package util;

import java.io.IOException;
import java.sql.*;
import java.util.Properties;

public class DBLink {
     static String username;
     static String password;
     static String url;
     static String driver;
     static {
        Properties p=new Properties();
        try {
            p.load(DBLink.class.getClassLoader().getResourceAsStream("jdbc.properties"));
        } catch (IOException e) {
            e.printStackTrace();
        }
        username=p.getProperty("username");
        password=p.getProperty("password");
        url=p.getProperty("url");
        driver=p.getProperty("driver");
        try {
            Class.forName(driver);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
    public static Connection getcon() throws SQLException {
        Connection con = DriverManager.getConnection(url,username,password);
        return con;
    }

    public static void main(String[] args) throws SQLException {

        System.out.println(getcon());
    }
}

Dao层

package DAO;

import pojo.Account;
import util.DBLink;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.LinkedList;
import java.util.List;

public class Dao {
    public static List<Account> getAll() throws SQLException {
        Connection con= DBLink.getcon();
        Statement st=con.createStatement();
        String sql="select * from cost2";
        ResultSet rs=st.executeQuery(sql);
        List<Account> ls=new LinkedList<>();
        while (rs.next()){
            Account acc=new Account();
            acc.setId(rs.getInt(1));
            acc.setName(rs.getString(2));
            acc.setBase_cost(rs.getDouble(3));
            acc.setStauts(rs.getString(4));
            ls.add(acc);
        }
        return ls;
    }
    public static void main(String[] args) throws SQLException {
        System.out.println(getAll().get(1).getId()+" "+getAll().get(1).getName()+getAll().get(1).getBase_cost()+" "+getAll().get(1).getStauts());
    }
}

Action控制层

package Action;

import DAO.Dao;
import com.opensymphony.xwork2.ActionSupport;
import pojo.Account;

import java.sql.SQLException;
import java.util.LinkedList;
import java.util.List;

public class OAction extends ActionSupport {
    List<Account> ls=new LinkedList<>();

    public List<Account> getLs() {
        return ls;
    }

    public void setLs(List<Account> ls) {
        this.ls = ls;
    }

    public String find() throws SQLException {
        ls= Dao.getAll();
        return "success";
    }
}

5. 页面上显示数据info.jsp利用迭代器

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <s:iterator value="ls" var="a">
        <s:property value="#a.id"/>
        <s:property value="#a.name"/>
        <s:property value="#a.base_cost"/>
        <s:property value="#a.stauts"/><br>
    </s:iterator>
</body>
</html>

6. 代码基本全部放出来了，可能写的项目流程我描述的不是很好，请见谅，最主要是学习怎么用代码连接oracle数据库，然后将数据显示到页面来。