毕业设计-1.09

情况概述：

　　连接数据库，并完成了通用方法的编写。

代码如下：

DBUtil.java

package com.zlc.util;

import java.sql.Connection;
import java.sql.DriverManager;

//数据库连接 SqlServer
public class DBUtil {
    // 驱动类名
    String driver = "com.mysql.jdbc.Driver";
    String url = "jdbc:mysql://localhost:3307/weather?useUnicode=true&characterEncoding=UTF8";// JavaTest为你的数据库名称
    String user = "root";
    String password = "364624";
    Connection coon = null;

    public Connection DBConnection() {
        Connection coon = null;
        try {
            // 加载驱动程序
            Class.forName(driver);
            coon = DriverManager.getConnection(url,user,password);
            if (!coon.isClosed()) {
                System.out.println("成功连接数据库！");
            } else {
                System.out.println("失败");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return coon;
    }

    public void close() {
        try {
            this.coon.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        DBUtil db = new DBUtil();
        db.DBConnection();
    }
}

CommonMethod.Java

package com.zlc.util;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.mysql.jdbc.Statement;

public class CommonMethod {
    public static Connection conn = null;
    public static PreparedStatement ps = null;
    public static ResultSet rs = null;

    /**
     * 
     * @Title: createPreParedStatement
     * @Description: PreParedStatement的创建方法
     * @param: @param sql
     * @param: @param params
     * @param: @return
     * @param: @throws SQLException   
     * @return: PreparedStatement   
     * @throws
     */
    public static PreparedStatement createPreParedStatement(String sql,Object[] params) throws SQLException {
        DBUtil db = new DBUtil();
        conn = db.DBConnection();
        ps = (PreparedStatement) conn.prepareStatement(sql);
        // 查询
        // set方法的个数依赖于？的个数，而？的个数与数组的个数一致
        if (params != null) {
            for (int i = 0; i < params.length; i++) {
                ps.setObject(i + 1, params[i]);
            }
        }
        return ps;
    }
    
    /**
     * 
     * @Title: executeUpdate
     * @Description: 通用的增刪改查
     * @param: @param sql 语句
     * @param: @param params 参数
     * @param: @return   
     * @return: boolean   是否完成操作
     * @throws
     */
    public static boolean executeUpdate(String sql, Object[] params) {
        try {
            ps = createPreParedStatement(sql, params);
            // 执行查询-返回值
            int count = ps.executeUpdate();
            if (count > 0) {
                return true;
            } else {
                return false;
            }
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        } finally {
            try {
                closeAll(rs, (Statement) ps, conn);
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 
     * @Title: executeQuery
     * @Description: 通用的查 返回值是一个集合
     * @param: @param sql 语句
     * @param: @param params 参数
     * @param: @return   
     * @return: ResultSet   返回集
     * @throws
     */
    public static ResultSet executeQuery(String sql, Object[] params) {
        try {
            ps = createPreParedStatement(sql, params);
            rs = ps.executeQuery();
            return rs;
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        }
    }
    
    /**
     * 
     * @Title: closeAll
     * @Description: 关闭数据库连接
     * @param: @param rs
     * @param: @param stmt
     * @param: @param conn
     * @param: @throws SQLException   
     * @return: void   
     * @throws
     */
    public static void closeAll(ResultSet rs,Statement stmt,Connection conn) throws SQLException {
        if (rs != null) {
            rs.close();
        }
        if (conn != null) {
            conn.close();
        }
        if (stmt != null) {
            stmt.close();
        }
    }

    /**
     * 
     * @Title: getTotalCount
     * @Description: 查询数据总数
     * @param: @param sql
     * @param: @return   
     * @return: int   
     * @throws
     */
    public static int getTotalCount(String sql) {
        int count = -1;
        try {
            ps = createPreParedStatement(sql, null);
            rs = ps.executeQuery();
            if (rs.next()) {
                count = rs.getInt(1);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            try {
                closeAll(rs, (Statement) ps, conn);
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        return count;
    }
    
    
    
}