JDBC连接数据库增删改查实例

查询所有

1. dao层代码：

package example;

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

import org.junit.Test;

import fengzhuang.Brand;

public class BrandTest {

	/**
	 * 1.sql语句：select * from tb_brand
	 * 2.参数：不需要
	 * 3.结果：List<Brand>
	 *
	 */

	@Test
	public void testSelectAll() throws Exception {
		//获取连接
		String url = "jdbc:mysql://localhost:3306/db1";
		String name = "root";
		String password = "123456";
		Connection conn = DriverManager.getConnection(url, name, password);
		//定义sql语句
		String sql = "select * from tb_brand";
		//获取对象
		PreparedStatement pstmt = conn.prepareStatement(sql);
		//执行sql
		ResultSet rs = pstmt.executeQuery();
		//处理结果
		Brand brand = null;
		List<Brand> brands = new ArrayList<>();
		while(rs.next()) {
			//获取数据
			int id = rs.getInt("id");
			String brandName = rs.getString("brand_name");
			String companyName = rs.getString("company_name");
			int ordered = rs.getInt("odered");
			String description = rs.getString("description");
			int status = rs.getInt("status");
			//封装对象
			brand = new Brand();
			brand.setId(id);
			brand.setBrandName(brandName);
			brand.setCompanyName(companyName);
			brand.setOrdered(ordered);
			brand.setDescription(description);
			brand.setStatus(status);
			//放到集合
			brands.add(brand);
		}
		System.out.println(brands);
		//释放资源
		rs.close();
		pstmt.close();
		conn.close();

	}

}

1. 数据类代码：

package fengzhuang;

public class Brand {
	private Integer id;
	private String brandName;
	private String companyName;
	private Integer ordered;
	private String description;
	private Integer status;

	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getBrandName() {
		return brandName;
	}
	public void setBrandName(String brandName) {
		this.brandName = brandName;
	}
	public String getCompanyName() {
		return companyName;
	}
	public void setCompanyName(String companyName) {
		this.companyName = companyName;
	}
	public Integer getOrdered() {
		return ordered;
	}
	public void setOrdered(Integer ordered) {
		this.ordered = ordered;
	}
	public String getDescription() {
		return description;
	}
	public void setDescription(String description) {
		this.description = description;
	}
	public Integer getStatus() {
		return status;
	}
	public void setStatus(Integer status) {
		this.status = status;
	}

	@Override
	public String toString() {
		return "Brand [id=" + id + ", brandName=" + brandName + ", companyName=" + companyName + ", ordered=" + ordered
				+ ", description=" + description + ", status=" + status + "]";
	}

}

1. 数据库表
   
   数据库名为db1，表名为tb_brand，数据库结构如下图：
   
   

2. 运行结果
   
   目前主要是学习JDBC，所有代码都是junit测试来运行的，暂时还没有前端界面。
   
   

添加数据

1. dao层代码

        /**
	 * 1.SQL语句：insert into tb_brand(brand_name,company_name,odered,description,status) values(?,?,?,?,?);
	 * 2.参数：需要，除了id外所有信息
	 * 3.结果：boolean
	 */

	@Test
	public void testAdd() throws Exception {
		//接受页面提交的参数
		String brandName = "香飘飘";
		String companyName = "香飘飘公司";
		int ordered = 1;
		String description = "香的要飘飘";
		int status = 1;
		//1. 获取连接
		String url = "jdbc:mysql://localhost:3306/db1";
		String name = "root";
		String password = "123456";
		Connection conn = DriverManager.getConnection(url, name, password);
		//2. 定义SQL语句
		String sql = "insert into tb_brand(brand_name,company_name,odered,description,status) values(?,?,?,?,?)";
		//3. 获取对象
		PreparedStatement pstmt = conn.prepareStatement(sql);
		//4. 设置参数
		pstmt.setString(1, brandName);
		pstmt.setString(2, companyName);
		pstmt.setInt(3, ordered);
		pstmt.setString(4, description);
		pstmt.setInt(5, status);
		//5. 执行SQL
		int count = pstmt.executeUpdate();
		//6. 处理结果
		System.out.println(count > 0);
		//7. 释放资源
		pstmt.close();
		conn.close();

	}

1. 数据类代码
   
   与查找相同

2. 数据库表结构
   
   与查找相同

3. 运行结果
   
   

修改

1. dao层代码：

        /**
	 * 1.SQL语句：update tb_brand set brand_name = ?,company_name = ?,odered = ?,description = ?,status = ? where id = ?
	 * 2.参数：需要，所有数据
	 * 3.结果：boolean
	 */

	@Test
	public void testUpdate() throws Exception {
		//接受页面提交的参数
		String brandName = "香飘飘";
		String companyName = "香飘飘公司";
		int ordered = 1000;
		String description = "直接起飞！";
		int status = 1;
		int id = 4;
		//1. 获取连接
		String url = "jdbc:mysql://localhost:3306/db1";
		String name = "root";
		String password = "123456";
		Connection conn = DriverManager.getConnection(url, name, password);
		//2. 定义SQL语句
		String sql = "update tb_brand set brand_name = ?,company_name = ?,odered = ?,description = ?,status = ? where id = ?";
		//3. 获取对象
		PreparedStatement pstmt = conn.prepareStatement(sql);
		//4. 设置参数
		pstmt.setString(1, brandName);
		pstmt.setString(2, companyName);
		pstmt.setInt(3, ordered);
		pstmt.setString(4, description);
		pstmt.setInt(5, status);
		pstmt.setInt(6, id);
		//5. 执行SQL
		int count = pstmt.executeUpdate();
		//6. 处理结果
		System.out.println(count > 0);
		//7. 释放资源
		pstmt.close();
		conn.close();

	}

1. 数据类代码
   
   与查询相同

2. 数据库结构
   
   与查询相同

3. 运行结果
   
   

删除

1. dao层代码

/**
	 * 1.SQL语句：delete from tb_brand where id = ?
	 * 2.参数：需要，id
	 * 3.结果：boolean
	 */

	@Test
	public void testDeleteById() throws Exception {
		//接受页面提交的参数
		int id = 4;
		//1. 获取连接
		String url = "jdbc:mysql://localhost:3306/db1";
		String name = "root";
		String password = "123456";
		Connection conn = DriverManager.getConnection(url, name, password);
		//2. 定义SQL语句
		String sql = "delete from tb_brand where id = ?";
		//3. 获取对象
		PreparedStatement pstmt = conn.prepareStatement(sql);
		//4. 设置参数
		pstmt.setInt(1, id);
		//5. 执行SQL
		int count = pstmt.executeUpdate();
		//6. 处理结果
		System.out.println(count > 0);
		//7. 释放资源
		pstmt.close();
		conn.close();

	}

1. 数据类代码：
   
   与查找相同

2. 数据库表结构
   
   与查找相同

3. 运行结果