java 常用的包

org.apache.commons.lang.StringUtils 常用方法

    <dependency>
       <groupId>org.apache.commons</groupId>
       <artifactId>commons-lang3</artifactId>
       <version>3.4</version>
  </dependency>

示例：

import org.apache.commons.lang.StringUtils;
 
public class Test{
    @SuppressWarnings({ "deprecation", "unused" })
    public static void test(String[] args) {
    	
    	/*************************判   空**********************************/
    	//判断是否Null 或者 "" 【不去空格】为空的标准是 str==null 或 str.length()==0 
    	boolean isEmpty = StringUtils.isEmpty("");//true
    	boolean isEmpty1 = StringUtils.isEmpty("  ");//false
    	boolean isEmptyNull = StringUtils.isEmpty(null);//true
    	// 判断是否Null 或者 "" 【去空格】为空的标准是 str==null 或 str.length()==0 
    	boolean isBlack = StringUtils.isBlank("");//true
    	boolean isBlack1 = StringUtils.isBlank("  ");//true
    	boolean isBlankNull = StringUtils.isBlank(null);//true
    	
    	
        //找到2个字符串第一个出现不同的位置（1开始）
        String difference = StringUtils.difference("s123", "s13");
        System.out.println(difference);//3
        
        //判断2个字符串是否相等
        boolean equals = StringUtils.equals("s1", "s1");
        System.out.println(equals);//true
        
        // 不区分大小写判断两个字符串是都相等
        boolean equalsIgnoreCase = StringUtils.equalsIgnoreCase("abc", "ABc");//true
        System.out.println(equalsIgnoreCase);
        
        //判断字符串里面是否含有特定字符串
        boolean b2 = StringUtils.contains("asd", "as");
        System.out.println(b2);//true
 
        //把数组的元素用:进行拼接
        String concatStr = StringUtils.join(new String[]{"dog", "cat", "monkey"},":");
        System.out.println(concatStr);//dog:cat:monkey
 
        //根据特定分隔符对字符串进行拆分
        String[] split = StringUtils.split("apple|xiaomi|dell|lenovo", "|");
        for (String s1 : split) {
            System.out.print(s1 + "、");//apple、xiaomi、dell、lenovo、
        }
        System.out.println();
        
        //所有单词首字母大写
        String capitaliseAllWords = StringUtils.capitaliseAllWords("today i will go to china");
        System.out.println(capitaliseAllWords);//Today I Will Go To China
 
        //统计某个字符串在字符串出现的次数
        int matchCount = StringUtils.countMatches("Happy Birthday to you", "o");
        System.out.println(matchCount);//2
 
        //必须要8位，不够的就拿0去字符串左边补 
        String leftPad = StringUtils.leftPad("54", 8, "0");
        System.out.println(leftPad);//00000054
        
        //必须要8位，不够的就拿0去字符串右边补 
        String rightPad = StringUtils.rightPad("54", 8, "0");
        System.out.println(rightPad);//54000000
 
        //判断字符串是否以特定字符串开头，区分大小写
        boolean startsWith = StringUtils.startsWith("GoodMorning", "go");
        System.out.println(startsWith);//false
        
        //判断字符串是否以特定字符串结尾，区分大小写
        boolean endsWith = StringUtils.endsWith("GoodMorning", "ing");
        System.out.println(endsWith);//true
        
        // 去空格
        StringUtils.trim("      222     ");//222
        
        //将null和""转换为null
        StringUtils.trimToNull("");//null
        
        // 将null和""转换为""
        StringUtils.trimToEmpty(null);//""
 
        //当第一个字符串为null或者""时返回第二个参数
        StringUtils.defaultIfEmpty(null, "sos");//sos
        StringUtils.defaultIfEmpty("", "sos");//sos
        StringUtils.defaultIfEmpty("111", "sos");//111
        
        // 去除参数首尾和第二个参数相同的字符,如果第二个参数为null那就去除首尾的空格
        StringUtils.strip("fsfsdf", "f");//sfsd
        StringUtils.strip("fsfsdfa", "f");//sfsdfa
        // 去除首部和第二个参数相同的字符,如果第二个参数为null那就去除首部的空格
        StringUtils.stripStart("ddsuuud", "d");//suuud
        // 去除尾部和第二个参数相同的字符,如果第二个参数为null那就去除尾部的空格
        StringUtils.stripEnd("ddsuuud", "d");//ddsuuu
        
        // 对数组整体去除首尾空格
        //java
        //c++
        //python    script
        String[] strip = StringUtils.stripAll(new String[]{"    java ", "c++     ", "python    script"});
    	for(String aa : strip){
    		System.out.println(aa);
    	}
        
    	// 去掉数据中首尾和第二个参数一样的字符
    	//java
        //hp
        //ython    script
        String[] strip1 = StringUtils.stripAll(new String[]{"    java ", "php     ", "python    script"},"p");
    	for(String aa : strip){
    		System.out.println(aa);
    	}
        
    	/**************************查找****************************/
    	// 查找第二个参数首次出现的位置(区分大小写)，如果第一个参数为null或者没有查找到时返回-1
    	StringUtils.indexOf("bbbb", "a");//-1
    	StringUtils.indexOf(null, "a");//-1
    	StringUtils.indexOf("aaaa", "a");//0
    	StringUtils.indexOf("aaaa", "A");//-1
    	
    	// 查找第二个参数首次出现的位置(不区分大小写)，如果第一个参数为null或者没有查找到时返回-1
    	StringUtils.indexOf("bbbb", "A");//-1
    	StringUtils.indexOf(null, "A");//-1
    	StringUtils.indexOf("aaaa", "A");//0
    	
    	
    }
    
    public static void main(String[] args) {
    	System.out.println(StringUtils.indexOfIgnoreCase("abbb", "A"));
	}
    
}

@Data（Lombok实现）

		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<version>1.18.22</version>
			<optional>true</optional>
		</dependency>

示例

package com.example.lombok;
 
import lombok.Data;
 
@Data
public class Student {
	private Integer id;
	private String name;
	private Integer gender;
	private Integer classId;
}
 

可选配置 如果想要在 Maven 打包的时候，Lombok 不被打包，可使用如下配置。

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <configuration>
                <excludes>
                    <exclude>
                        <groupId>org.projectlombok</groupId>
                        <artifactId>lombok</artifactId>
                    </exclude>
                </excludes>
            </configuration>
        </plugin>
    </plugins>
</build>

java利用POI解析Excel及图片

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>3.17</version>
        </dependency>
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>3.17</version>
        </dependency>

package com.betawoo.admin.test.base;
import com.betawoo.admin.commons.utils.QiNiuUtils;
import org.apache.poi.POIXMLDocumentPart;
import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.*;
import org.openxmlformats.schemas.drawingml.x2006.spreadsheetDrawing.CTMarker;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
 * Created by hgg on 2019/5/7.
 */
public class POIExcel {
    public static void getDataFromExcel(String filePath) throws IOException
    {
        //判断是否为excel类型文件
        if(!filePath.endsWith(".xls")&&!filePath.endsWith(".xlsx"))
        {
            System.out.println("文件不是excel类型");
        }
        FileInputStream fis =null;
        Workbook wookbook = null;
        Sheet sheet =null;
        try
        {
            //获取一个绝对地址的流
            fis = new FileInputStream(filePath);
            /* 读取网络文件（比如七牛等云存储）
            URL url = new URL(filePath);
            BufferedInputStream fis = new BufferedInputStream(url.openStream());*/
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
        try
        {
            //2003版本的excel，用.xls结尾
            wookbook = new HSSFWorkbook(fis);//得到工作簿
        }
        catch (Exception ex)
        {
            //ex.printStackTrace();
            try
            {
                //2007版本的excel，用.xlsx结尾
                fis = new FileInputStream(filePath);
                wookbook = new XSSFWorkbook(fis);//得到工作簿
            } catch (IOException e)
            {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        Map<String, PictureData> maplist=null;
        sheet = wookbook.getSheetAt(0);
        // 判断用07还是03的方法获取图片
        if (filePath.endsWith(".xls")) {
            maplist = getPictures1((HSSFSheet) sheet);
        } else if(filePath.endsWith(".xlsx")){
            maplist = getPictures2((XSSFSheet) sheet);
        }
        try {
            printImg(maplist);
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            //释放map
            if (maplist != null){
                maplist = null;
            }
        }
        //得到一个工作表
        //获得表头
        Row rowHead = sheet.getRow(0);
		
        //获得数据的总行数
        int totalRowNum = sheet.getLastRowNum();
        //要获得属性
        String proName="";
        String space="";
        String size="";
        String brand="";
        String unit="";
        Integer num=null;
        Double unitPrice=null;
        Double total=null;
        String material="";
        String remark="";
        String pic="";
        //获得所有数据
        System.out.println("产品名称\t\t空间\t\t规格/尺寸\t\t品牌\t\t单位\t\t数量\t\t单价\t\t金额\t\t材质\t\t备注");
        for(int i = 1 ; i < totalRowNum ; i++)
        {
            //获得第i行对象
            Row row = sheet.getRow(i);
            
            //空间位置(为空则停止解析)
            Cell cell = row.getCell(0);
            if (cell == null){
                break;
            }
            cell.setCellType(CellType.STRING);
            space =cell.getStringCellValue().toString();
            if (StringUtils.isBlank(space)){
                break;
            }
 
            //产品名称
            cell = row.getCell(1);
            if (cell != null){
                cell.setCellType(CellType.STRING);
                proName =  cell.getStringCellValue();
            }
            //规格/尺寸
            cell = row.getCell(3);
            if (cell != null){
                cell.setCellType(CellType.STRING);
                size =cell.getStringCellValue()+"";
            }
            //品牌
            cell = row.getCell(4);
            if (cell != null){
                cell.setCellType(CellType.STRING);
                brand =cell.getStringCellValue()+"";
            }
            //单位
            cell = row.getCell(5);
            if (cell != null){
                cell.setCellType(CellType.STRING);
                unit =cell.getStringCellValue()+"";
            }
            //数量
            cell = row.getCell(6);
            if (cell != null){
                num =(int)cell.getNumericCellValue();
            }
            //单价
            cell = row.getCell(7);
            if (cell != null){
                unitPrice =cell.getNumericCellValue();
            }
            //金额
            cell = row.getCell(8);
            if (cell != null){
                total =cell.getNumericCellValue();
            }
            //材质
            cell = row.getCell(9);
            if (cell != null){
                cell.setCellType(CellType.STRING);
                material =cell.getStringCellValue()+"";
            }
            //备注
            cell = row.getCell(10);
            if (cell != null){
                cell.setCellType(CellType.STRING);
                remark =cell.getStringCellValue()+"";
            }
            System.out.println(proName+"\t\t"+space+"\t\t"+size+"\t\t"+brand+"\t\t"+unit+"\t\t"+num+"\t\t"
                    +unitPrice+"\t\t"+total+"\t\t"+material+"\t\t"+remark);
        }
        for (Map.Entry<String, PictureData> entry : maplist.entrySet()) {
            System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
        }
        //使用完成关闭
        wookbook.close();
        if (fis != null){
            fis.close();
        }
    }
    /**
     * 获取图片和位置 (xls)
     * @param sheet
     * @return
     * @throws IOException
     */
    public static Map<String, PictureData> getPictures1 (HSSFSheet sheet) throws IOException {
        Map<String, PictureData> map = new HashMap<String, PictureData>();
        List<HSSFShape> list = sheet.getDrawingPatriarch().getChildren();
        for (HSSFShape shape : list) {
            if (shape instanceof HSSFPicture) {
                HSSFPicture picture = (HSSFPicture) shape;
                HSSFClientAnchor cAnchor = (HSSFClientAnchor) picture.getAnchor();
                PictureData pdata = picture.getPictureData();
                String key = cAnchor.getRow1() + "-" + cAnchor.getCol1(); // 行号-列号
                map.put(key, pdata);
            }
        }
        return map;
    }
    /**
     * 获取图片和位置 (xlsx)
     * @param sheet
     * @return
     * @throws IOException
     */
    public static Map<String, PictureData> getPictures2 (XSSFSheet sheet) throws IOException {
        Map<String, PictureData> map = new HashMap<String, PictureData>();
        List<POIXMLDocumentPart> list = sheet.getRelations();
        for (POIXMLDocumentPart part : list) {
            if (part instanceof XSSFDrawing) {
                XSSFDrawing drawing = (XSSFDrawing) part;
                List<XSSFShape> shapes = drawing.getShapes();
                for (XSSFShape shape : shapes) {
                    XSSFPicture picture = (XSSFPicture) shape;
                    XSSFClientAnchor anchor = picture.getPreferredSize();
                    CTMarker marker = anchor.getFrom();
                    String key = marker.getRow() + "-" + marker.getCol();
                    map.put(key, picture.getPictureData());
                }
            }
        }
        return map;
    }
    //图片写出
    public static void printImg(Map<String, PictureData> sheetList) throws Exception {
        Object key[] = sheetList.keySet().toArray();
        String filePath = "";
        for (int i = 0; i < sheetList.size(); i++) {
            // 获取图片流
            PictureData pic = sheetList.get(key[i]);
            // 获取图片索引
            String picName = key[i].toString();
            // 获取图片格式
            String ext = pic.suggestFileExtension();
            byte[] data = pic.getData();
            //文件上传七牛
//            QiNiuUtils.uploadOneObject(data,"111_"+picName + "." + ext);
            //图片保存路径
            filePath = "D:\\img\\pic" + picName + "." + ext;
            System.out.println(filePath);
            FileOutputStream out = new FileOutputStream(filePath);
            out.write(data);
            out.close();
        }
    }
    public static void main(String[] args) throws Exception {
        getDataFromExcel("D:"+ File.separator +"test.xlsx");
    }
}

java csv文件读取包

    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-csv</artifactId>
        <version>1.8</version> <!-- 请检查是否有更新的版本 -->
    </dependency>

示例

在Java中，可以使用不同的库来读取CSV文件，其中最常用的是Apache Commons CSV和OpenCSV。
 
下面是使用Apache Commons CSV读取CSV文件的示例代码：
 
java
import org.apache.commons.csv.*;
 
import java.io.FileReader;
import java.io.IOException;
import java.util.List;
 
public class CSVReader {
    public static void main(String[] args) {
        try {
            FileReader reader = new FileReader("data.csv");
            Iterable<CSVRecord> records = CSVFormat.DEFAULT.withFirstRecordAsHeader().parse(reader);
            for (CSVRecord record : records) {
                String name = record.get("Name");
                int age = Integer.parseInt(record.get("Age"));
                System.out.println("Name: " + name + ", Age: " + age);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}
 
// 例假设CSV文件的第一行是标题行，其中包含“Name”和“Age”列名。在循环中，我们使用record.get()方法获取每个列的值，并使用System.out.println()将其打印到控制台。
 
// 想使用OpenCSV库，可以使用以下示例代码：
 
java
import com.opencsv.CSVReader;
import java.io.FileReader;
import java.io.IOException;
 
public class CSVReader {
    public static void main(String[] args) {
        try {
            CSVReader reader = new CSVReader(new FileReader("data.csv"));
            String[] nextLine;
            while ((nextLine = reader.readNext()) != null) {
                String name = nextLine[0];
                int age = Integer.parseInt(nextLine[1]);
                System.out.println("Name: " + name + ", Age: " + age);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } catch (NumberFormatException e) {
            e.printStackTrace();
        }
    }
}
 
// 例使用CSVReader类读取CSV文件，并使用readNext()方法逐行读取数据。注意，我们假设CSV文件中的第一列是名称，第二列是年龄。