封装JDBC操作数据库的方法

自己动手封装java操作数据库的方法：

一：目录结构

二：所需依赖的第三方jar包

这里只需引入mysql-connector-java-5.1.8-bin.jar，mysql数据库驱动jar包

三：代码

1：和数据库进行交互，首先是数据源，获取连接，代码如下：

/**
 * 
 */
package com.hlcui.datasource;

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

/**
 * @author Administrator 定义获取和关闭数据源的方法
 */
public class DataSourceUtil {

    /**
     * 注册数据库驱动
     */
    static {
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    /**
     * 获取数据源
     * 
     * @throws SQLException
     */
    public static Connection getConnection(String url, String user,
            String password) throws SQLException {
        return DriverManager.getConnection(url, user, password);
    }

    /**
     * 关闭数据源
     * 
     * @throws SQLException
     */
    public static void closeConnection(Connection conn) throws SQLException {
        if (null != conn) {
            conn.close();
        }
    }
}

2：有个数据库连接之后，可以对数据库进行操作了

/**
 * 
 */
package com.hlcui.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import com.hlcui.Constants;
import com.hlcui.datasource.DataSourceUtil;
import com.hlcui.entity.Student;

/**
 * @author Administrator
 * 
 */
public class DBUtil {

    /**
     * 查询所有学生信息
     * 
     * @return
     */
    public static List<Student> getAllStuInfo() {
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        List<Student> stus = new ArrayList<Student>();
        try {
            conn = DataSourceUtil.getConnection(Constants.URL,
                    Constants.USERNAME, Constants.PASSWORD);
            String sql = "select * from student";
            ps = conn.prepareStatement(sql);
            rs = ps.executeQuery();
            while (rs.next()) {
                int id = rs.getInt("id");
                String name = rs.getString("name");
                int age = rs.getInt("age");
                double score = rs.getDouble("score");
                Student s = new Student(id, name, age, score);
                stus.add(s);
            }

        } catch (Exception e) {
            e.printStackTrace();
        } finally {

            try {
                if (null != rs) {
                    rs.close();
                }
                if (null != ps) {
                    ps.close();
                }
                if (null != conn) {
                    DataSourceUtil.closeConnection(conn);
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }

        }
        return stus;
    }

    /**
     * 根据id查询学生的信息
     */
    public static Student getStuInfoById(int id) {
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        Student s = null;
        try {
            conn = DataSourceUtil.getConnection(Constants.URL,
                    Constants.USERNAME, Constants.PASSWORD);
            String sql = "SELECT * FROM student where id = ?";
            ps = conn.prepareStatement(sql);
            ps.setInt(1, id);
            rs = ps.executeQuery();
            while (rs.next()) {
                String name = rs.getString("name");
                int age = rs.getInt("age");
                double score = rs.getDouble("score");
                s = new Student(id, name, age, score);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (null != rs) {
                    rs.close();
                }
                if (null != ps) {
                    ps.close();
                }
                if (null != conn) {
                    DataSourceUtil.closeConnection(conn);
                }
            } catch (Exception e2) {
            }
        }
        return s;
    }

    /**
     * 增加学生信息
     */
    public static void saveStuInfo(Student stu) {
        Connection conn = null;
        PreparedStatement ps = null;
        try {
            conn = DataSourceUtil.getConnection(Constants.URL,
                    Constants.USERNAME, Constants.PASSWORD);
            String sql = "insert into student (id,name,age,score) values (?,?,?,?)";
            ps = conn.prepareStatement(sql);
            ps.setInt(1, stu.getId());
            ps.setString(2, stu.getName());
            ps.setInt(3, stu.getAge());
            ps.setDouble(4, stu.getScore());
            int insertCount = ps.executeUpdate();
            System.out.println(isSuccess(insertCount));
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (null != ps) {
                    ps.close();
                }
                if (null != conn) {
                    conn.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
    }

    /**
     * 根据id删除学生信息
     */
    public static void deleteStuInfo(int id) {
        Connection conn = null;
        PreparedStatement ps = null;
        try {
            conn = DataSourceUtil.getConnection(Constants.URL,
                    Constants.USERNAME, Constants.PASSWORD);
            String sql = "delete from student where id = ?";
            ps = conn.prepareStatement(sql);
            ps.setInt(1, id);
            int deleteCount = ps.executeUpdate();
            System.out.println(isSuccess(deleteCount));
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (null != ps) {
                    ps.close();
                }
                if (null != conn) {
                    conn.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
    }

    /**
     * 根据id修改学生信息
     */
    public static void modifyStuInfo(Student stu) {
        Connection conn = null;
        PreparedStatement ps = null;
        try {
            conn = DataSourceUtil.getConnection(Constants.URL,
                    Constants.USERNAME, Constants.PASSWORD);
            String sql = "update student set name = ?,age = ? ,score = ? where id = ?";
            ps = conn.prepareStatement(sql);
            ps.setString(1, stu.getName());
            ps.setInt(2, stu.getAge());
            ps.setDouble(3, stu.getScore());
            ps.setInt(4, stu.getId());
            int count = ps.executeUpdate();
            System.out.println(isSuccess(count));
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (null != ps) {
                    ps.close();
                }
                if (null != conn) {
                    conn.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
    }

    /**
     * 判断操作是否成功
     */
    public static String isSuccess(int count) {
        if (count > 0) {
            return "操作成功！";
        } else {
            return "操作失败！";
        }
    }
}

3：POJO实体类

/**
 * 
 */
package com.hlcui.entity;

/**
 * @author Administrator
 * 
 */
public class Student {
    private int id;
    private String name;
    private int age;
    private double score;

    public Student() {

    }

    public Student(int id, String name, int age, double score) {
        super();
        this.id = id;
        this.name = name;
        this.age = age;
        this.score = score;
    }

    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 int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public double getScore() {
        return score;
    }

    public void setScore(double score) {
        this.score = score;
    }

}

4：常量类Constants

/**
 * 
 */
package com.hlcui;

/**
 * @author Administrator
 * 
 */
public class Constants {

    public static final String URL = "jdbc:mysql://localhost:3306/test";
    public static final String USERNAME = "root";
    public static final String PASSWORD = "root";

}

四：测试类，验证是否能够操作数据库中数据

/**
 * 
 */
package com.hlcui.test;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.Iterator;
import java.util.List;

import org.junit.Test;

import com.hlcui.Constants;
import com.hlcui.dao.DBUtil;
import com.hlcui.datasource.DataSourceUtil;
import com.hlcui.entity.Student;

/**
 * @author Administrator
 * 
 */
public class TestJdbc {

    /**
     * 测试获取数据库连接
     * 
     * @throws SQLException
     */
    @Test
    public void testGetConnection() throws SQLException {
        Connection conn = DataSourceUtil.getConnection(Constants.URL,
                Constants.USERNAME, Constants.PASSWORD);
        System.out.println("conn:" + conn);

    }

    /**
     * 测试获取所有的学生信息
     */
    @Test
    public void testGetAllStuInfo() {
        List<Student> stus = DBUtil.getAllStuInfo();
        Iterator<Student> it = stus.iterator();
        while (it.hasNext()) {
            Student s = it.next();
            System.out.println(s.getId() + "," + s.getName() + "," + s.getAge()
                    + "," + s.getScore());
        }
    }

    /**
     * 测试根据id获取学生信息
     */
    @Test
    public void testGetStuInfoById() {
        int id = 1;
        Student s = DBUtil.getStuInfoById(id);
        System.out.println(s.getId() + "," + s.getName() + "," + s.getAge()
                + "," + s.getScore());
    }

    /**
     * 测试添加学生信息
     */
    @Test
    public void testSaveStuInfo() {
        Student s = new Student(4, "Lucy", 27, 100.0);
        DBUtil.saveStuInfo(s);
    }

    /**
     * 测试删除学生信息
     */
    @Test
    public void testDeleteStuInfo() {
        int id = 4;
        DBUtil.deleteStuInfo(id);
    }
    
    /**
     * 测试修改学生信息
     */
    @Test
    public void testModifyStuInfo(){
        Student s = new Student(3,"Lili",24,9000.0);
        DBUtil.modifyStuInfo(s);
    }

}

以上代码均已验证正确。