题目
使用IDEA 创建 MAVEN JAVA 项目
根据下图 在mysql数据库中创建员工表(T_Employee)
创建实体类 Employee 并创建DAO 层(使用JDBC技术)
以及测试类 对创建的DAO实现类进行增删改查进行测试
项目目录结构
1.在数据库中创建表T_Employee(大小写无所谓)
DROP TABLE IF EXISTS t_employee;
CREATE TABLE t_employee (
id int(11) NOT NULL AUTO_INCREMENT,
name varchar(30) DEFAULT NULL,
age int(11) DEFAULT NULL,
birthday date DEFAULT NULL,
salary decimal(10,0) DEFAULT NULL,
PRIMARY KEY (id)
)
2.创建实体类Employee
package com.xiongluoluo.bean;
import lombok.*;
import java.math.BigDecimal;
import java.util.Date;
/**
* Created by Administrator on 2019/12/21 0021.
*/
@Getter
@Setter
@ToString
@AllArgsConstructor
@NoArgsConstructor
public class Employee {
private int id;
private String name;
private int age;
private Date birthday;
private BigDecimal salary;
}
2.创建Dao层之前,按照以前的方式,我们需要导入JDBC的jar包,然后导入C3P0的jar包,以及dbutils的jar包,在src下写一个c3p0-config.xml文件.但是现在我们使用了maven去创建项目,需要导包的只需在pom.xml中添加依赖即可.需要写在src下的c3p0-config.xml文件只需放在src-->main-->resources文件夹(这个文件夹必须标记为resource root,不然读不到)下即可.
2.1 pom.xml文件
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.xiongluoluo</groupId>
<artifactId>maven3</artifactId>
<version>1.0.0</version>
<dependencies>
<!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
<!--lombok插件的依赖-->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.8</version>
<scope>provided</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<!--JDBC的依赖(在https://mvnrepository.com中搜索mysql,点击第一个即可)-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.38</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.mchange/c3p0 -->
<!--c3p0的依赖(在https://mvnrepository.com中搜索c3p0,点击第一个即可)-->
<dependency>
<groupId>com.mchange</groupId>
<artifactId>c3p0</artifactId>
<version>0.9.5.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/commons-dbutils/commons-dbutils -->
<!--dbutils的依赖(在https://mvnrepository.com中搜索dbutils,点击第一个即可)-->
<dependency>
<groupId>commons-dbutils</groupId>
<artifactId>commons-dbutils</artifactId>
<version>1.6</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
</dependencies>
</project>
2.2 c3p0-config.xml文件
<?xml version="1.0" encoding="UTF-8" ?>
<c3p0-config>
<default-config>
<property name="driverClass">com.mysql.jdbc.Driver</property>
<property name="jdbcUrl">jdbc:mysql://localhost:3306/test2</property>
<property name="user">root</property>
<property name="password">1234</property>
</default-config>
</c3p0-config>
2.3 EmployeDao.java文件
package com.xiongluoluo.dao;
import com.xiongluoluo.bean.Employee;
import java.util.List;
/**
* Created by Administrator on 2019/12/21 0021.
*/
public interface EmployeeDao {
//增加员工
public int addEmployee(Employee employee);
//通过id删除员工
public int deleteEmployeeById(int id);
//修改员工信息
public int updateEmployee(Employee employee);
//查询员工信息
public Employee queryEmployeeById(int id);
//查询全部员工信息
public List<Employee> queryAllEmployee();
}
2.4 EmployeeDaoImpl.java文件
package com.xiongluoluo.dao.impl;
import com.xiongluoluo.bean.Employee;
import com.xiongluoluo.dao.EmployeeDao;
import com.xiongluoluo.utils.C3p0Util;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import java.util.List;
/**
* Created by Administrator on 2019/12/21 0021.
*/
public class EmployeeDaoImpl implements EmployeeDao{
public int addEmployee(Employee employee) {
QueryRunner queryRunner = new QueryRunner(C3p0Util.getDataSource());
String sql = "insert into t_employee values(null,?,?,?,?)";
int result = 0;
try {
result = queryRunner.update(sql,new Object[]{employee.getName(),employee.getAge(),employee.getBirthday(),employee.getSalary()});
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
public int deleteEmployeeById(int id) {
QueryRunner queryRunner = new QueryRunner(C3p0Util.getDataSource());
String sql = "delete from t_employee where id = ?";
int result = 0;
try {
result = queryRunner.update(sql,id);
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
public int updateEmployee(Employee employee) {
QueryRunner queryRunner = new QueryRunner(C3p0Util.getDataSource());
String sql = "update t_employee set name=?,age=?,birthday=?,salary=? where id = ?";
int result = 0;
try {
result = queryRunner.update(sql,employee.getName(),employee.getAge(),employee.getBirthday(),employee.getSalary(),employee.getId());
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
public Employee queryEmployeeById(int id) {
QueryRunner queryRunner = new QueryRunner(C3p0Util.getDataSource());
String sql = "select id,name,age,birthday,salary from t_employee where id=?";
Employee employee = null;
try {
employee = queryRunner.query(sql,new BeanHandler<Employee>(Employee.class),id);
} catch (Exception e) {
e.printStackTrace();
}
return employee;
}
public List<Employee> queryAllEmployee() {
QueryRunner queryRunner = new QueryRunner(C3p0Util.getDataSource());
String sql = "select id,name,age,birthday,salary from t_employee";
List<Employee> list = null;
try {
list = queryRunner.query(sql,new BeanListHandler<Employee>(Employee.class));
} catch (Exception e) {
e.printStackTrace();
}
return list;
}
}
3 Dao层中需要用的一些工具类
3.1 C3p0获取数据源的工具类
package com.xiongluoluo.utils;
import com.mchange.v2.c3p0.ComboPooledDataSource;
import javax.sql.DataSource;
/**
* Created by Administrator on 2019/12/21 0021.
*/
public class C3p0Util {
private static DataSource dataSource = new ComboPooledDataSource();
public static DataSource getDataSource(){
return dataSource;
}
}
3.2 字符串转日期工具类
package com.xiongluoluo.utils;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
/**
* Created by Administrator on 2019/12/21 0021.
*/
public class DateUtil {
public static Date strToDate(String str){
Date date = null;
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
try {
date = simpleDateFormat.parse(str);
} catch (ParseException e) {
e.printStackTrace();
}
return date;
}
}
4 测试类
package com.xiongluoluo.test;
import com.xiongluoluo.bean.Employee;
import com.xiongluoluo.dao.EmployeeDao;
import com.xiongluoluo.dao.impl.EmployeeDaoImpl;
import com.xiongluoluo.utils.DateUtil;
import org.junit.Test;
import java.math.BigDecimal;
import java.util.Date;
import java.util.List;
import java.util.Scanner;
/**
* Created by Administrator on 2019/12/21 0021.
*/
public class EmployeeTest {
//增加员工
@Test
public void testAddEmployee(){
Scanner sc = new Scanner(System.in);
try{
System.out.println("请输入name:");
String name = sc.nextLine();
System.out.print("请输入age:");
int age = Integer.parseInt(sc.nextLine());
System.out.println("请输入生日(格式1998-01-02):");
Date birthday = DateUtil.strToDate(sc.nextLine());
System.out.println("请输入工资:");
BigDecimal salary = new BigDecimal(sc.nextLine());
Employee employee = new Employee();
employee.setName(name);
employee.setAge(age);
employee.setBirthday(birthday);
employee.setSalary(salary);
EmployeeDao employeeDao = new EmployeeDaoImpl();
int result = employeeDao.addEmployee(employee);
if(result>0){
System.out.println("添加成功!");
}else{
System.out.println("添加失败!");
}
}catch (Exception e){
System.out.println("您输入的格式不正确!");
//e.printStackTrace();
}
}
//通过id删除员工
@Test
public void testDeleteEmployeeById(){
Scanner sc = new Scanner(System.in);
System.out.println("请输入id(数字):");
try{
int id = Integer.parseInt(sc.nextLine());
EmployeeDao employeeDao = new EmployeeDaoImpl();
int result = employeeDao.deleteEmployeeById(id);
if(result>0){
System.out.println("删除成功!");
}else{
System.out.println("删除失败!");
}
}catch (Exception e){
System.out.println("您输入的格式不正确!");
//e.printStackTrace();
}
}
//修改员工信息
@Test
public void testUpdateEmployee(){
Scanner sc = new Scanner(System.in);
System.out.println("请输入id(数字):");
try{
int id = Integer.parseInt(sc.nextLine());
EmployeeDao employeeDao = new EmployeeDaoImpl();
Employee employee = employeeDao.queryEmployeeById(id);
if(employee!=null){
int result = employeeDao.updateEmployee(employee);
if(result>0){
System.out.println("更新成功!");
}else{
System.out.println("更新失败!");
}
}else{
System.out.println("您输入的id不存在!");
}
}catch (Exception e){
System.out.println("您输入的格式不正确!");
//e.printStackTrace();
}
}
//查询员工信息
@Test
public void testQueryEmployeeById(){
Scanner sc = new Scanner(System.in);
System.out.println("请输入id(数字):");
try{
int id = Integer.parseInt(sc.nextLine());
EmployeeDao employeeDao = new EmployeeDaoImpl();
Employee employee = employeeDao.queryEmployeeById(id);
if(employee!=null){
System.out.println(employee.getName()+"\t"+employee.getAge()+"\t"+employee.getBirthday()+"\t"+employee.getSalary());
}else{
System.out.println("您输入的id不存在!");
}
}catch (Exception e){
System.out.println("您输入的格式不正确!");
//e.printStackTrace();
}
}
//查询全部员工信息
@Test
public void testQueryAllEmployee(){
EmployeeDao employeeDao = new EmployeeDaoImpl();
List<Employee> employeeList = employeeDao.queryAllEmployee();
for(Employee employee:employeeList){
System.out.println(employee.getName()+"\t"+employee.getAge()+"\t"+employee.getBirthday()+"\t"+employee.getSalary());
}
}
}
这样配置项目之后编译之后的结果为:
虽然这个项目很简单,但是也让我感觉到maven的好处.像以前我写这种项目的时候,就得导很多包,然后放文件什么的.但是有了maven,只需导入依赖即可.还有c3p0-config.xml文件也帮忙处理了.感觉maven这个工具还是很棒的,就是一开始做的时候,没有真正理解maven的用法,所以遇到一些坑,不过现在算是理解清楚了.
