Java基础（maven）——maven新建项目 & 常用IO工具 & Durid数据库工具 & 案例

引出

如何用maven新建项目，用maven建项目的优势，常用的io工具和durid工具

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用Maven建项目

0.Maven配置方式

参考博客 ：
【配置】Maven的配置 & Tomcat的配置 & 在IDEA中新建web项目

中的maven配置

1.io流的工具IOUtils/FileUtils

1）可以读文件、按照行读、读网页等；

package com.tianju.io;

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;

import java.io.*;
import java.net.URL;
import java.util.List;

public class ReadFileDemo1 {
    public static void main(String[] args) throws IOException {
        // IOUtils 进行读取
        /**
         * IOUtils.readLines 读取一个文件，把文件中的每一行放在一个List中
         * 两个参数： 1.要读取文件的输入流 FileInputStream；
         *          2.编码形式，通常为"UTF-8"
         */
        List<String> stringList = IOUtils.readLines(new FileInputStream("D:\\Myprogram\\jf_map_utf8.txt"),
                "UTF-8");

        stringList.forEach(System.out::println);

        // 读文件
        List<String> in = FileUtils.readLines(new File("D:\\Myprogram\\jf_map_utf8.txt"),"UTF-8");
        System.out.println(in);

        // 读网页
        URL url = new URL("https://www.baidu.com");
        InputStream inputStream = url.openStream();
        List<String> stringList1 = IOUtils.readLines(inputStream,"UTF-8");
        stringList1.forEach(System.out::println);


    }
}

2）配合hasmap进行简体繁体转换

package com.tianju.io;

import org.apache.commons.io.FileUtils;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class TransferDemo1 {
    public static void main(String[] args) throws IOException {
        String filePath = "D:\\Myprogram\\jf_map_utf8.txt";
        List<String> in = FileUtils.readLines(new File(filePath),"UTF-8");
        // 把list 转成 map，高效查找
        Map<String,String> map = new HashMap<>(1000);

        for (String i:in){
            String[] iSplit = i.split(":");
            map.put(iSplit[0],iSplit[1]);
        }

        // 转换单个字的方法
        System.out.println(map);
        String inStr = "发";
        System.out.println(map.get(inStr));

        // 转换一句话的方法
        String inWord = "我家住在东北6564呵呵，恭喜发财";
        StringBuilder outWord = new StringBuilder();
        char[] chars = inWord.toCharArray();
        for (char c:chars){
            // 如果是中文字符，则进行繁体字的转换
            if (Character.UnicodeScript.of(c)==Character.UnicodeScript.HAN){
                if (map.get(c+"")!=null){
                    outWord.append(map.get(c+""));
                }else {
                    outWord.append(c);
                }
            }else {
                // 否则直接加加进去
                outWord.append(c);
            }
        }
        System.out.println(outWord);


    }
}

2.durid数据库连接工具

1）创建连接，durid进行连接管理

（1）用durid去连接数据库，创建多个connection；

（2）要用到connection的时候，找durid要；

连接数据库的两种url写法：

 String url = "jdbc:mysql://127.0.0.1:3306/javaweb06?useUnicode=true&characterEncoding=UTF-8&userSSL=false&serverTimezone=GMT%2B8";
String url = "jdbc:mysql://"+ip+"?useSSL=false&serverTimezone=Asia/Shanghai&allowPublicKeyRetrieval=true";

package com.tianju.dataSource;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.pool.DruidPooledConnection;

import java.sql.SQLException;

/**
 * 1.用 druid 去连接数据库，创建多个connection
 * 2.要用到connection 的时候，找druid要
 */
public class DruidDemo {
    public static void main(String[] args) throws SQLException {
        String driverClassname = "com.mysql.cj.jdbc.Driver";
        String ip = "192.168.111.128:3306/rec_db";
        String url = "jdbc:mysql://"+ip+"?useSSL=false&serverTimezone=Asia/Shanghai&allowPublicKeyRetrieval=true";
        String username = "root";
        String password = "123";

        // 1.创建Druid 的连接对象，会一次性创建10个连接
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(driverClassname);
        dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);
        dataSource.setMaxActive(10); // 让数据库一次性建立10个连接

        // 2.使用一个连接，问druid要一个连接
        DruidPooledConnection connection = dataSource.getConnection();
        System.out.println(connection);

    }
}

2）查询的方式queryForObject、query，queryForRowSet

推荐使用queryForObject、query

RowMapper<Emp> userRowMapper = new BeanPropertyRowMapper<>(Emp.class);
List<Emp> empList = jdbcTemplate.query("SELECT * FROM emp_tab", userRowMapper);

根据id查单个的方式：

    public Phone findById(Integer id) {
        List<Phone> find = db.query("SELECT * FROM t_phone WHERE id = ?", rowMapper,id);
        if (find.size()>0){
            return find.get(0);
        }
        System.out.println("Not found");
        return null;
    }

package com.tianju.dataSource;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.pool.DruidPooledConnection;
import com.tianju.entity.Emp;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.support.rowset.SqlRowSet;

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

public class JdbcTmpelateDemo {
    public static void main(String[] args) throws SQLException {
        String driverClassname = "com.mysql.cj.jdbc.Driver";
        String ip = "192.168.111.128:3306/emp_db";
        String url = "jdbc:mysql://"+ip+"?useSSL=false&serverTimezone=Asia/Shanghai&allowPublicKeyRetrieval=true";
        String username = "root";
        String password = "123";

        // 1.创建Druid 的连接对象，会一次性创建10个连接
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(driverClassname);
        dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);
        dataSource.setMaxActive(10); // 让数据库一次性建立10个连接

        // 2.jdbcTemplate, 操作数据库的工具类，类似于DBUtils
        JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);

        // 增删改
        jdbcTemplate.update("INSERT INTO emp_tab(emp_name, emp_gender) VALUES (?,?)","张三","女");

        // 查询，不建议用此方法
       SqlRowSet rs  = jdbcTemplate.queryForRowSet("SELECT * FROM emp_tab");
       List<Emp> list = new ArrayList<>(10);
       while (rs.next()){
           Emp emp = new Emp(
                   rs.getInt("id"),
                   rs.getString("name"),
                   rs.getString("gender"),
                   rs.getInt("age"),
                   rs.getDouble("sal"),
                   rs.getString("job")
           );
           list.add(emp);
       }
       System.out.println(list);

       // 查询的第二种方式，这种方式更好
        RowMapper<Emp> userRowMapper = new BeanPropertyRowMapper<>(Emp.class);
        List<Emp> empList = jdbcTemplate.query("SELECT * FROM emp_tab", userRowMapper);
        System.out.println("-----------------");
        System.out.println(empList);


    }
}

案例：把电话号码导入到数据库

0.pom.xml配置

<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/maven-v4_0_0.xsd">
  <modelVersion>4.0.0modelVersion>
  <groupId>com.tianjugroupId>
  <artifactId>JavaWebPhoneartifactId>
  <packaging>warpackaging>
  <version>1.0-SNAPSHOTversion>

  <properties>
    <project.build.sourceEncoding>UTF-8project.build.sourceEncoding>
    <maven.compiler.source>1.8maven.compiler.source>
    <maven.compiler.target>1.8maven.compiler.target>
  properties>

  <dependencies>
    <dependency>
      <groupId>javax.servletgroupId>
      <artifactId>javax.servlet-apiartifactId>
      <version>4.0.1version>
      
      <scope>providedscope>
    dependency>

    <dependency>

      <groupId>org.projectlombokgroupId>
      <artifactId>lombokartifactId>
      <version>1.18.22version>
    dependency>

    <dependency>

      <groupId>commons-iogroupId>
      <artifactId>commons-ioartifactId>
      <version>2.5version>
    dependency>

    <dependency>

      <groupId>com.alibabagroupId>
      <artifactId>druidartifactId>
      <version>1.2.16version>
    dependency>

    <dependency>

      <groupId>mysqlgroupId>
      <artifactId>mysql-connector-javaartifactId>
      <version>8.0.20version>
    dependency>

    <dependency>

      <groupId>org.springframeworkgroupId>
      <artifactId>spring-jdbcartifactId>
      <version>5.2.22.RELEASEversion>
    dependency>

    <dependency>

      <groupId>junitgroupId>
      <artifactId>junitartifactId>
      <version>3.8.1version>
      <scope>testscope>
    dependency>
      <dependency>
          <groupId>junitgroupId>
          <artifactId>junitartifactId>
          <version>RELEASEversion>
          <scope>compilescope>
      dependency>

  dependencies>

project>

web.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
</web-app>

1.读取文件存到数据库

package com.tianju.test;

import com.sun.org.apache.bcel.internal.generic.NEW;
import com.tianju.util.DBUtils;
import org.apache.commons.io.FileUtils;
import org.junit.Test;
import org.springframework.jdbc.core.JdbcTemplate;

import java.io.File;
import java.io.IOException;
import java.util.List;

public class SaveToSQLDemo1 {
    public static void main(String[] args) throws IOException {
        JdbcTemplate db = DBUtils.getJdbcTemplate();
        String filePath = "D:\\Myprogram\\files\\phone1.csv";
        List<String> stringList = FileUtils.readLines(new File(filePath),"UTF-8");
        for (int i =1;i<stringList.size();i++){
            String[] sSplit = stringList.get(i).split(",");
            System.out.println(sSplit[1] + sSplit[2] + sSplit[3]);
            db.update("INSERT INTO t_phone(mobile_number,mobile_area,mobile_type,create_time,update_time) " +
                    "VALUES (?,?,?,now(),now())",sSplit[1],sSplit[2],sSplit[3]);
        }
    }

    @Test // 加入test注解，让普通方法变成可运行
    public void insertInSQL() throws IOException {
        JdbcTemplate db = DBUtils.getJdbcTemplate();
        String filePath = "D:\\Myprogram\\files\\phone1.csv";
        List<String> stringList = FileUtils.readLines(new File(filePath),"UTF-8");
        for (int i =1;i<stringList.size();i++){
            String[] sSplit = stringList.get(i).split(",");
            System.out.println(sSplit[1] + sSplit[2] + sSplit[3]);
            db.update("INSERT INTO t_phone(mobile_number,mobile_area,mobile_type,create_time,update_time) " +
                    "VALUES (?,?,?,now(),now())",sSplit[1],sSplit[2],sSplit[3]);
        }

    }
}

2.DBUtils

package com.tianju.util;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.jdbc.core.JdbcTemplate;

/**
 * 1.连接数据库--durid
 * 2.提供jdbcTemplate
 */
public class DBUtils {
    private static DruidDataSource dataSource =null;
    static {
        String driverClassname = "com.mysql.cj.jdbc.Driver";
        String ip = "127.0.0.1:3306/javaweb06";
        // jdbc:mysql://127.0.0.1:3306/javaweb06?useUnicode=true&characterEncoding=UTF-8&userSSL=false&serverTimezone=GMT%2B8
        String url = "jdbc:mysql://"+ip+"?useSSL=false&serverTimezone=Asia/Shanghai&allowPublicKeyRetrieval=true";
        String username = "root";
        String password = "123";
        dataSource = new DruidDataSource();
        dataSource.setDriverClassName(driverClassname);
        dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);
    }

    /**
     *
     * @return 返回一个JdbcTemplate对象
     */
    public static JdbcTemplate getJdbcTemplate(){
        return new JdbcTemplate(dataSource);
    }


}

3.Dao层的代码【查单个/多个，统计数量】

接口部分

package com.tianju.dao;

import com.tianju.entity.Phone;

import java.util.List;

public interface IPhoneDao {

    // 添加一条数据
    /**
     * 增加一条数据
     * @param phone 增加的实体类
     * @return 返回影响的行数
     */
    Integer add(Phone phone);

    // 修改
    /**
     * 修改
     * @param phone 修改的实体类，根据该实体类的id进行定位和修改
     * @return 影响行数
     */
    Integer update(Phone phone);

    // 根据id删除一条数据
    /**
     * 根据id删除一条数据
     * @param id 删除的索引id
     * @return 影响行数
     */
    Integer deleteById(Integer id);

    // 查询所有
    /**
     * 查询数据库中所有的数据
     * @return 查询到的list
     */
    List<Phone> queryAll();

    // 根据id查询
    Phone findById(Integer id);

    // 根据mobile_number进行查询
    /**
     * 根据号码查询归属地等信息
     * @param mobileNumber 查找的电话number
     * @return 返回查找的
     */
    Phone selectByMobileNumber(String mobileNumber);

    // 查询数据条数
    /**
     * 查找所有的行数
     * @return 总的行数
     */
    Integer countDataLines();

}

实现类

package com.tianju.dao.impl;

import com.tianju.dao.IPhoneDao;
import com.tianju.entity.Phone;
import com.tianju.util.DBUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;

import java.util.List;

public class PhoneDaoImpl implements IPhoneDao {
    private JdbcTemplate db;
    private RowMapper<Phone> rowMapper;

    public PhoneDaoImpl() {
        db = DBUtils.getJdbcTemplate();
        rowMapper = new BeanPropertyRowMapper<>(Phone.class);
    }

    @Override
    public Integer add(Phone phone) {
        return db.update("INSERT INTO t_phone(id,mobile_number,mobile_area,mobile_type,create_time,update_time) VALUES " +
                "(NULL,?,?,?,now(),now())",phone.getMobileNumber(),phone.getMobileArea(),phone.getMobileType());
    }

    @Override
    public Integer update(Phone phone) {
        return db.update("UPDATE t_phone SET mobile_number=?,mobile_area=?,mobile_type=?,update_time=now() WHERE id=?",
                phone.getMobileNumber(),phone.getMobileArea(),phone.getMobileType(),phone.getId());
    }

    @Override
    public Integer deleteById(Integer id) {
        return db.update("DELETE FROM t_phone WHERE id = ?", id);
    }

    @Override
    public List<Phone> queryAll() {
        return db.query("SELECT * FROM t_phone", rowMapper);
    }

    @Override
    public Phone findById(Integer id) {
        List<Phone> find = db.query("SELECT * FROM t_phone WHERE id = ?", rowMapper,id);
        if (find.size()>0){
            return find.get(0);
        }
        System.out.println("Not found");
        return null;
    }

    @Override
    public Phone selectByMobileNumber(String mobileNumber) {
        List<Phone> find = db.query("SELECT * FROM t_phone WHERE mobile_number = ?", rowMapper,mobileNumber);
        if (find.size()>0){
            return find.get(0);
        }
        System.out.println("Not found");
        return null;
    }

    @Override
    public Integer countDataLines() {
        // 要用.queryForObject方法
        return db.queryForObject("SELECT COUNT(*) FROM t_phone", Integer.class);
    }
}

4.实体类

package com.tianju.entity;

import lombok.*;

import java.util.Date;
@Data
@AllArgsConstructor
@NoArgsConstructor
@Setter @Getter
public class Phone {
    private Integer id;
    private String mobileNumber;
    private String mobileArea;
    private String mobileType;
    private Date createTime; // springJDBC可以把数据中下划线转成createTime
    private Date updateTime;

    @Override
    public String toString() {
        return "\nPhone{" +
                "id=" + id +
                ", mobileNumber='" + mobileNumber + '\'' +
                ", mobileArea='" + mobileArea + '\'' +
                ", mobileType='" + mobileType + '\'' +
                ", createTime=" + createTime +
                ", updateTime=" + updateTime +
                '}';
    }
}

5.进行测试

package test;

import com.tianju.dao.IPhoneDao;
import com.tianju.dao.impl.PhoneDaoImpl;
import com.tianju.entity.Phone;
import org.junit.Test;

import java.util.stream.Collectors;

public class PhoneDaoTest {
    private IPhoneDao dao = new PhoneDaoImpl();
    @Test
    public void add(){
        // 添加
        System.out.println(dao.countDataLines());
        System.out.println(dao.add(new Phone(null, "测试", "测试1", "南京", null, null)));
        System.out.println(dao.countDataLines());
    }

    @Test
    public void update(){
        // 修改
        System.out.println(dao.findById(300107));
        System.out.println(dao.update(new Phone(300107, "南京", "江宁", "hehe", null, null)));
        System.out.println(dao.findById(300107));
    }

    @Test
    public void query(){
        // 查询
        System.out.println(dao.countDataLines());
        System.out.println(dao.queryAll().stream().limit(10).collect(Collectors.toList()));
        System.out.println(dao.selectByMobileNumber("1880222"));
    }

    @Test
    public void delete(){
        System.out.println(dao.deleteById(300106));
    }


}

---

总结

1.maven的作用，及其配置，新建maven项目方法；
2.常用的IO工具，读取文件的方法，读取到成字符串行；
3.durid数据库连接工具，查询的方法，query；