Java--jdbc--orm-- List-- Json

DB_Select_Demo.java

 

package com.syc.test.DB;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import com.syctest.bean.UpdateListBean;

public class DB_Select_Demo {
	public static void main(String[] args) {
		System.out.println(selectDB());
	}

	public static List<UpdateListBean> selectDB() {
		Connection conn = null;
		Statement st = null;
		ResultSet rs = null;
		List<UpdateListBean> list=new ArrayList<UpdateListBean>();
		String text = "00";
		// mysql的加载JDBC驱动程序
		try {
			Class.forName("com.mysql.jdbc.Driver");
		} catch (ClassNotFoundException e) {
			System.out.println("驱动加载错误");
			e.printStackTrace();
		}
		// 与mysql数据库建立连接
		try {
			conn = DriverManager.getConnection(
					"jdbc:mysql://localhost:3306/sva_rec", "root", "mysql");
		} catch (SQLException e) {
			System.out.println("数据库链接错误");
			e.printStackTrace();
		}
		// 创建Statement
		try {
			st = conn.createStatement();
			// 创建一个JDBC声明
			String query ="SELECT dt, year,month FROM date_drv ORDER BY dt,MONTH DESC LIMIT 1,10";
			rs = st.executeQuery(query);
			while (rs.next()) {
				UpdateListBean ulBean=new UpdateListBean();
				ulBean.setYear(rs.getString("year"));
				ulBean.setDt(rs.getString("dt"));
				ulBean.setMonth(rs.getString("month"));
				
				list.add(ulBean);
			}
		} catch (SQLException e1) {
			System.out.println("数据操作错误");
			e1.printStackTrace();
		}
		// 关闭数据库
		try {
			if (rs != null) {
				rs.close();
				rs = null;
			}
			if (st != null) {
				st.close();
				st = null;
			}
			if (conn != null) {
				conn.close();
				conn = null;
			}
		} catch (Exception e) {
			System.out.println("数据库关闭错误");
			e.printStackTrace();
		}
		return list;
	}
}

 

 

UpdateList2Json.java

package com.syctest.JSON;

import java.util.ArrayList;
import java.util.List;

import net.sf.json.JSONArray;

import com.syc.test.DB.DB_Select_Demo;
import com.syctest.bean.UpdateListBean;

public class UpdateList2Json {
	public static void main(String[] args) {
		UpdateList2Json();
	}

	private static void UpdateList2Json() {
		List<UpdateListBean> list = new ArrayList<UpdateListBean>();
		list = DB_Select_Demo.selectDB();
		for (int i = 0; i < list.size(); i++) {
			// System.out.println(list.get(i).getYear()+" "+list.get(i).getMonth()+" "+list.get(i).getDt()
			// );
		}

		for (int i = 0; i < list.size(); i++) {
			int maxNum = Integer.parseInt(list.get(0).getMonth());
			int objNum = Integer.parseInt(list.get(i).getMonth()) * 100
					/ maxNum;
			System.out.println(maxNum + " " + objNum);
			list.get(i).setRate(String.valueOf(objNum));
		}
		for (int i = 0; i < list.size(); i++) {
			System.out.println(list.get(i).getYear() + " "
					+ list.get(i).getMonth() + " " + list.get(i).getDt() + " "
					+ list.get(i).getRate());
		}
		JSONArray ja = JSONArray.fromObject(list);
		System.out.println(ja.toString());

	}

}

 

 

UpdateListBean.java

package com.syctest.bean;

public class UpdateListBean {
	public String rate;
	public String getRate() {
		return rate;
	}

	public void setRate(String rate) {
		this.rate = rate;
	}

	public String year;

	public String getYear() {
		return year;
	}

	public void setYear(String year) {
		this.year = year;
	}

	public String getMonth() {
		return month;
	}

	public void setMonth(String month) {
		this.month = month;
	}

	public String getDt() {
		return dt;
	}

	public void setDt(String dt) {
		this.dt = dt;
	}

	public String month;
	public String dt;
}