java poi插入数据到已经存在的excel但不覆盖原来的数据 怎么实现 在线等待...

Posted 2023-04-15

参考技术A poi的Sheet对象可以获取最后一行位置，如int lastRowNum = sheet.getLastRowNum(); 知道最后一行位置，就可以在最后一行后面开始加入新数据，如Row row = sheet.getRow(lastRowNum+1);追问

我是用的一个单独的方法啊 这样的话就新new了一个HSSFWorkbook 不知道怎么判断excel已经存在 而且我也是在开始的位置加啊...

追答

说下你想完成什么样的功能吧

本回答被提问者采纳

java poi技术读取到数据库

https://www.cnblogs.com/hongten/p/java_poi_excel.html

java的poi技术读取Excel数据到MySQL

这篇blog是介绍java中的poi技术读取Excel数据，然后保存到MySQL数据中。

你也可以在 ： java的poi技术读取和导入Excel 了解到写入Excel的方法信息

使用JXL技术可以在 ： java的jxl技术导入Excel

项目结构：

Excel中的测试数据：

数据库结构：

对应的SQL：
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1 CREATE TABLE student_info (
2 id int(11) NOT NULL AUTO_INCREMENT,
3 no varchar(20) DEFAULT NULL,
4 name varchar(20) DEFAULT NULL,
5 age varchar(10) DEFAULT NULL,
6 score float DEFAULT \'0\',
7 PRIMARY KEY (id)
8 ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

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插入数据成功：

如果重复数据，则丢掉：

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源码部分：

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/ExcelTest/src/com/b510/client/Client.java
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1 /**
2 *
3 /
4 package com.b510.client;
5
6 import java.io.IOException;
7 import java.sql.SQLException;
8
9 import com.b510.excel.SaveData2DB;
10
11 /*
12 * @author Hongten
13 * @created 2014-5-18
14 */
15 public class Client {
16
17 public static void main(String[] args) throws IOException, SQLException {
18 SaveData2DB saveData2DB = new SaveData2DB();
19 saveData2DB.save();
20 System.out.println("end");
21 }
22 }

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/ExcelTest/src/com/b510/common/Common.java
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1 /**
2 *
3 /
4 package com.b510.common;
5
6 /*
7 * @author Hongten
8 * @created 2014-5-18
9 */
10 public class Common {
11
12 // connect the database
13 public static final String DRIVER = "com.mysql.jdbc.Driver";
14 public static final String DB_NAME = "test";
15 public static final String USERNAME = "root";
16 public static final String PASSWORD = "root";
17 public static final String IP = "192.168.1.103";
18 public static final String PORT = "3306";
19 public static final String URL = "jdbc:mysql://" + IP + ":" + PORT + "/" + DB_NAME;
20
21 // common
22 public static final String EXCEL_PATH = "lib/student_info.xls";
23
24 // sql
25 public static final String INSERT_STUDENT_SQL = "insert into student_info(no, name, age, score) values(?, ?, ?, ?)";
26 public static final String UPDATE_STUDENT_SQL = "update student_info set no = ?, name = ?, age= ?, score = ? where id = ? ";
27 public static final String SELECT_STUDENT_ALL_SQL = "select id,no,name,age,score from student_info";
28 public static final String SELECT_STUDENT_SQL = "select * from student_info where name like ";
29 }

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/ExcelTest/src/com/b510/excel/ReadExcel.java
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1 /**
2 *
3 /
4 package com.b510.excel;
5
6 import java.io.FileInputStream;
7 import java.io.IOException;
8 import java.io.InputStream;
9 import java.util.ArrayList;
10 import java.util.List;
11
12 import org.apache.poi.hssf.usermodel.HSSFCell;
13 import org.apache.poi.hssf.usermodel.HSSFRow;
14 import org.apache.poi.hssf.usermodel.HSSFSheet;
15 import org.apache.poi.hssf.usermodel.HSSFWorkbook;
16
17 import com.b510.common.Common;
18 import com.b510.excel.vo.Student;
19
20 /*
21 * @author Hongten
22 * @created 2014-5-18
23 */
24 public class ReadExcel {
25
26 public List readXls() throws IOException {
27 InputStream is = new FileInputStream(Common.EXCEL_PATH);
28 HSSFWorkbook hssfWorkbook = new HSSFWorkbook(is);
29 Student student = null;
30 List list = new ArrayList();
31 // 循环工作表Sheet
32 for (int numSheet = 0; numSheet < hssfWorkbook.getNumberOfSheets(); numSheet++) {
33 HSSFSheet hssfSheet = hssfWorkbook.getSheetAt(numSheet);
34 if (hssfSheet == null) {
35 continue;
36 }
37 // 循环行Row
38 for (int rowNum = 1; rowNum <= hssfSheet.getLastRowNum(); rowNum++) {
39 HSSFRow hssfRow = hssfSheet.getRow(rowNum);
40 if (hssfRow != null) {
41 student = new Student();
42 HSSFCell no = hssfRow.getCell(0);
43 HSSFCell name = hssfRow.getCell(1);
44 HSSFCell age = hssfRow.getCell(2);
45 HSSFCell score = hssfRow.getCell(3);
46 student.setNo(getValue(no));
47 student.setName(getValue(name));
48 student.setAge(getValue(age));
49 student.setScore(Float.valueOf(getValue(score)));
50 list.add(student);
51 }
52 }
53 }
54 return list;
55 }
56
57 @SuppressWarnings("static-access")
58 private String getValue(HSSFCell hssfCell) {
59 if (hssfCell.getCellType() == hssfCell.CELL_TYPE_BOOLEAN) {
60 // 返回布尔类型的值
61 return String.valueOf(hssfCell.getBooleanCellValue());
62 } else if (hssfCell.getCellType() == hssfCell.CELL_TYPE_NUMERIC) {
63 // 返回数值类型的值
64 return String.valueOf(hssfCell.getNumericCellValue());
65 } else {
66 // 返回字符串类型的值
67 return String.valueOf(hssfCell.getStringCellValue());
68 }
69 }
70 }

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/ExcelTest/src/com/b510/excel/SaveData2DB.java
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1 /**
2 *
3 /
4 package com.b510.excel;
5
6 import java.io.IOException;
7 import java.sql.SQLException;
8 import java.util.List;
9
10 import com.b510.common.Common;
11 import com.b510.excel.util.DbUtil;
12 import com.b510.excel.vo.Student;
13
14 /*
15 * @author Hongten
16 * @created 2014-5-18
17 */
18 public class SaveData2DB {
19
20 @SuppressWarnings({ "rawtypes" })
21 public void save() throws IOException, SQLException {
22 ReadExcel xlsMain = new ReadExcel();
23 Student student = null;
24 List list = xlsMain.readXls();
25
26 for (int i = 0; i < list.size(); i++) {
27 student = list.get(i);
28 List l = DbUtil.selectOne(Common.SELECT_STUDENT_SQL + "\'%" + student.getName() + "%\'", student);
29 if (!l.contains(1)) {
30 DbUtil.insert(Common.INSERT_STUDENT_SQL, student);
31 } else {
32 System.out.println("The Record was Exist : No. = " + student.getNo() + " , Name = " + student.getName() + ", Age = " + student.getAge() + ", and has been throw away!");
33 }
34 }
35 }
36 }

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/ExcelTest/src/com/b510/excel/util/DbUtil.java
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1 /**
2 *
3 /
4 package com.b510.excel.util;
5
6 import java.sql.Connection;
7 import java.sql.DriverManager;
8 import java.sql.PreparedStatement;
9 import java.sql.ResultSet;
10 import java.sql.SQLException;
11 import java.util.ArrayList;
12 import java.util.List;
13
14 import com.b510.common.Common;
15 import com.b510.excel.vo.Student;
16
17 /*
18 * @author Hongten
19 * @created 2014-5-18
20 /
21 public class DbUtil {
22
23 /*
24 * @param sql
25 */
26 public static void insert(String sql, Student student) throws SQLException {
27 Connection conn = null;
28 PreparedStatement ps = null;
29 try {
30 Class.forName(Common.DRIVER);
31 conn = DriverManager.getConnection(Common.URL, Common.USERNAME, Common.PASSWORD);
32 ps = conn.prepareStatement(sql);
33 ps.setString(1, student.getNo());
34 ps.setString(2, student.getName());
35 ps.setString(3, student.getAge());
36 ps.setString(4, String.valueOf(student.getScore()));
37 boolean flag = ps.execute();
38 if(!flag){
39 System.out.println("Save data : No. = " + student.getNo() + " , Name = " + student.getName() + ", Age = " + student.getAge() + " succeed!");
40 }
41 } catch (Exception e) {
42 e.printStackTrace();
43 } finally {
44 if (ps != null) {
45 ps.close();
46 }
47 if (conn != null) {
48 conn.close();
49 }
50 }
51 }
52
53 @SuppressWarnings({ "unchecked", "rawtypes" })
54 public static List selectOne(String sql, Student student) throws SQLException {
55 Connection conn = null;
56 PreparedStatement ps = null;
57 ResultSet rs = null;
58 List list = new ArrayList();
59 try {
60 Class.forName(Common.DRIVER);
61 conn = DriverManager.getConnection(Common.URL, Common.USERNAME, Common.PASSWORD);
62 ps = conn.prepareStatement(sql);
63 rs = ps.executeQuery();
64 while(rs.next()){
65 if(rs.getString("no").equals(student.getNo()) || rs.getString("name").equals(student.getName())|| rs.getString("age").equals(student.getAge())){
66 list.add(1);
67 }else{
68 list.add(0);
69 }
70 }
71 } catch (Exception e) {
72 e.printStackTrace();
73 } finally {
74 if (rs != null) {
75 rs.close();
76 }
77 if (ps != null) {
78 ps.close();
79 }
80 if (conn != null) {
81 conn.close();
82 }
83 }
84 return list;
85 }
86
87
88 public static ResultSet selectAll(String sql) throws SQLException {
89 Connection conn = null;
90 PreparedStatement ps = null;
91 ResultSet rs = null;
92 try {
93 Class.forName(Common.DRIVER);
94 conn = DriverManager.getConnection(Common.URL, Common.USERNAME, Common.PASSWORD);
95 ps = conn.prepareStatement(sql);
96 rs = ps.executeQuery();
97 } catch (Exception e) {
98 e.printStackTrace();
99 } finally {
100 if (rs != null) {
101 rs.close();
102 }
103 if (ps != null) {
104 ps.close();
105 }
106 if (conn != null) {
107 conn.close();
108 }
109 }
110 return rs;
111 }
112
113 }

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/ExcelTest/src/com/b510/excel/vo/Student.java
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1 /**
2 *
3 /
4 package com.b510.excel.vo;
5
6 /*
7 * Student
8 *
9 * @author Hongten
10 * @created 2014-5-18
11 /
12 public class Student {
13 /*
14 * id
15 /
16 private Integer id;
17 /*
18 * 学号
19 /
20 private String no;
21 /*
22 * 姓名
23 /
24 private String name;
25 /*
26 * 学院
27 /
28 private String age;
29 /*
30 * 成绩
31 */
32 private float score;
33
34 public Integer getId() {
35 return id;
36 }
37
38 public void setId(Integer id) {
39 this.id = id;
40 }
41
42 public String getNo() {
43 return no;
44 }
45
46 public void setNo(String no) {
47 this.no = no;
48 }
49
50 public String getName() {
51 return name;
52 }
53
54 public void setName(String name) {
55 this.name = name;
56 }
57
58 public String getAge() {
59 return age;
60 }
61
62 public void setAge(String age) {
63 this.age = age;
64 }
65
66 public float getScore() {
67 return score;
68 }
69
70 public void setScore(float score) {
71 this.score = score;
72 }
73
74 }

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源码下载：http://files.cnblogs.com/hongten/ExcelTest.zip

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More reading,and english is important.

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