JDBC数据读写基本操作

编写DAO数据处理组件

定义添加数据方法

定义更新数据方法

定义删除数据方法

定义各种业务查询数据方法

package com.xzit.dao;

import com.xzit.db.util.DataSourceManager;
import com.xzit.pojo.Department;

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

/*
* 数据访问处理组件，实现对dep_tab 部门表进行增，删，改，查操作
* */
public class DepartmentDao {

    /*
    * 添加新部门的方法
    * @param dep 新添加的部门
    * */
    public int addDepartment(Department dep){
        int res = 0;
        String sql="insert into dep_table " +
                "(id,name,createtime,descs) values (?,?,?,?)";  //sql插入语句
        Connection conn = DataSourceManager.getConnection();    //获取数据库连接
        PreparedStatement ps = null;    //获取PreparedStatement接口对象

        try {
            ps = conn.prepareStatement(sql);    //获取PreparedStatement对象
            /* 设置替换sql语句中的参数占位符? */
            ps.setString(1,"NO008");
            ps.setString(2,dep.getName());
            ps.setDate(3,new java.sql.Date(dep.getCreateDate().getTime()));
            ps.setString(4,dep.getDescs());
            res = ps.executeUpdate();

        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {  //关闭数据库连接，释放资源
            DataSourceManager.close(ps);
            DataSourceManager.close(conn);
        }
        return res;
    }

    /**
     * 修改选定的部门对象
     * @param dep 欲修改的部门
     * @return
     */
    public int modifyDepartment(Department dep){
        int res = 0;
        String sql = "update dep_table set name = ?,createtime=?,descs=? "
                + "where id=?";
        Connection conn = DataSourceManager.getConnection();    //获取数据库连接
        PreparedStatement ps = null;    //获取PreparedStatement接口对象

        try {
            ps = conn.prepareStatement(sql);
            ps.setString(1,dep.getName());
            ps.setDate(2,new java.sql.Date(dep.getCreateDate().getTime()));
            ps.setString(3,dep.getDescs());
            ps.setString(4,dep.getId());
            res = ps.executeUpdate();
        } catch (Exception ex) {
            ex.printStackTrace();
        }finally {
            DataSourceManager.close(ps);
            DataSourceManager.close(conn);
        }
        return res;
    }

    /**
     * 删除部门对象
     * @param id 删除部门的id
     * @return
     */
    public int deleteDepartmentById(String id){
        int res = 0;
        String sql = "delete from dep_table where id = '"+id+"'";
        Connection conn = DataSourceManager.getConnection();    //获取连接
        PreparedStatement ps = null;    //获取PreparedStatement接口对象

        try {
            ps = conn.prepareStatement(sql);
            //执行删除操作
            res = ps.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        }finally {  //关闭数据库连接
            DataSourceManager.close(ps);
            DataSourceManager.close(conn);
        }
        return res;
    }
}

package com.xzit.test;

import com.xzit.dao.DepartmentDao;
import com.xzit.pojo.Department;

import java.util.Date;

public class TestInset {
    public static void main(String[] args) {

        Department dep = new Department();
        dep.setName("测试二部");
        dep.setCreateDate(new Date());
        dep.setDescs("测试部辅助部门");

        int res = new DepartmentDao().addDepartment(dep);
        System.out.println("影响数据库表的行数是 "+res);
    }
}

package com.xzit.db.util;

import java.sql.*;

/*
* 数据源管理组件，提供最基本的通用的数据库连接
* */
public final class DataSourceManager {

    /*
    * 提供目标数据源的连接通用方法
    * */
    public static Connection getConnection(){

        Connection conn = null;
        /* 加载数据库驱动 */
        try {
            /* 加载数据库驱动 */
            Class.forName(Env.JDBC_DRIVER);
            conn = DriverManager.getConnection(Env.JDBC_URL,Env.JDBC_USER,Env.JDBC_PASSWORD);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return conn;
    }

    /*
    * 关闭数据库连接的通用方法
    * */
    public static void close(Connection conn){//关闭Connection

        try {
            if(conn != null && conn.isClosed()){
                conn.close();   //关闭数据库连接
            }
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }

    public static void close(Statement state){
        try {
            if (state != null && state.isClosed()){
                state.close();
            }
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }

    public static void close(ResultSet set){
        try {
            if (set != null && !set.isClosed()){
                set.close();
            }
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }
}

package com.xzit.db.util;

import java.util.ResourceBundle;

public final class Env {
    /* 存储从属性文件读取的数据库属性配置信息 */
    public static final String JDBC_URL;
    public static final String JDBC_DRIVER;
    public static final String JDBC_USER;
    public static final String JDBC_PASSWORD;
    static {
        /* 获取配置文件的名称，使用getBundle()方法 */
        ResourceBundle resourceBundle = ResourceBundle.getBundle("dbconf");//不需要写后缀名
        /* 获取资源文件中的信息：使用getString()方法 */
        JDBC_URL=resourceBundle.getString("jdbc_url");
        JDBC_DRIVER=resourceBundle.getString("jdbc_driver");
        JDBC_USER=resourceBundle.getString("jdbc_user");
        JDBC_PASSWORD=resourceBundle.getString("jdbc_password");
    }
        public static void main(String[] args) {
        System.out.println(Env.JDBC_DRIVER);
        System.out.println(Env.JDBC_URL);
        System.out.println(Env.JDBC_USER);

    }
}

package com.xzit.pojo;

import java.util.Date;

/*
* 映射dep_tab 部门信息表的实体类
* */
public class Department {

    private String id;
    private String name;
    private Date createDate;
    private String descs;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Date getCreateDate() {
        return createDate;
    }

    public void setCreateDate(Date createDate) {
        this.createDate = createDate;
    }

    public String getDescs() {
        return descs;
    }

    public void setDescs(String descs) {
        this.descs = descs;
    }
}

package com.xzit.test;

import com.xzit.dao.DepartmentDao;

public class TestDelete {
    public static void main(String[] args) {
        String id = "NO008";    //被删除部门对象的id(主键)
        int res = new DepartmentDao().deleteDepartmentById(id);
        System.out.println(res+" 条数据被删除");
    }
}