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。