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請(qǐng)問(wèn)使用java如何獲得數(shù)據(jù)庫(kù)表中各字段的字段名?

請(qǐng)問(wèn)使用java如何獲得數(shù)據(jù)庫(kù)表中各字段的字段名?

月關(guān)寶盒 2021-11-18 11:11:34
比如我傳給rs一條SQL語(yǔ)句,"select * from TableName" ,我想得到TableName的字段名,這樣我就可以把一條結(jié)果保存到HashTable里,整個(gè)結(jié)果同樣可以放到HashList里,方便jsp頁(yè)面上的JSTL取值,最好付上整個(gè)DB代碼內(nèi)容,謝謝
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慕姐8265434

TA貢獻(xiàn)1813條經(jīng)驗(yàn) 獲得超2個(gè)贊

import java.sql.*;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;public class Test{ public static void main(String[] args) throws Exception {
// 驅(qū)動(dòng)
String driver = "com.mysql.jdbc.Driver";
// 數(shù)據(jù)庫(kù)連接
String url = "jdbc:mysql://localhost:3306/test";
// 用戶名
String user = "root";
// 數(shù)據(jù)庫(kù)密碼
String password = "admin";
// 加載驅(qū)動(dòng)
Class.forName(driver);
// 獲取鏈接
Connection connection = DriverManager
.getConnection(url, user, password);
// 創(chuàng)建查詢聲明
PreparedStatement preparedStatement = connection
.prepareStatement("select * from dept");
// 獲取結(jié)果
ResultSet resultSet = preparedStatement.executeQuery();
// 獲取各個(gè)列的信息
ResultSetMetaData metaData = resultSet.getMetaData();
// 一條數(shù)據(jù)保存在一個(gè)Hashtable 將所有Hashtable存放到list
List<Hashtable<String, Object>> rows = new ArrayList<Hashtable<String, Object>>();
while (resultSet.next()) {
Hashtable<String, Object> row = new Hashtable<String, Object>();
for (int i = 1; i <= metaData.getColumnCount(); i++) {
// 打印列名
System.out.println(metaData.getColumnName(i));
row.put(metaData.getColumnName(i), resultSet.getObject(i));
}
rows.add(row);
}
resultSet.close();
preparedStatement.close();
connection.close();
}}



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MMMHUHU

TA貢獻(xiàn)1834條經(jīng)驗(yàn) 獲得超8個(gè)贊

參考如下例子,利用jdbc獲取到結(jié)果集后,利用ResultSetMetaData的方法就可以取到字段名了!
package com.javacodegeeks.snippets.core;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;

public class RetrieveColumnNamesExample {

public static void main(String[] args) {

Connection connection = null;
try {

// 加載jdbc驅(qū)動(dòng)

String driverName = "com.mysql.jdbc.Driver";

Class.forName(driverName);

//創(chuàng)建連接

String serverName = "localhost";

String schema = "test";

String url = "jdbc:mysql://" + serverName + "/" + schema;

String username = "username";

String password = "password";

connection = DriverManager.getConnection(url, username, password);

System.out.println("Successfully Connected to the database!");

} catch (ClassNotFoundException e) {

System.out.println("Could not find the database driver " + e.getMessage());
} catch (SQLException e) {

System.out.println("Could not connect to the database " + e.getMessage());
}

try {

// 創(chuàng)建結(jié)果集

Statement statement = connection.createStatement();

ResultSet results = statement.executeQuery("SELECT * FROM test_table");

// 獲取 metadata

ResultSetMetaData metadata = results.getMetaData();

// 從 metadata中獲取列的個(gè)數(shù)
int columnCount = metadata.getColumnCount();

System.out.println("test_table columns : ");

//循環(huán)獲取列的名字并打印

for (int i=1; i<=columnCount; i++) {

String columnName = metadata.getColumnName(i);

System.out.println(columnName);

}

} catch (SQLException e) {

System.out.println("Could not retrieve database metadata " + e.getMessage());
}
}
}

其中以下的重點(diǎn)代碼片段:
ResultSet results = statement.executeQuery("SELECT * FROM test_table");

// 獲取 metadata

ResultSetMetaData metadata = results.getMetaData();

// 從 metadata中獲取列的個(gè)數(shù)
int columnCount = metadata.getColumnCount();

System.out.println("test_table columns : ");

//循環(huán)獲取列的名字并打印

for (int i=1; i<=columnCount; i++) {

String columnName = metadata.getColumnName(i);

System.out.println(columnName);

}

 


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