我需要我的代码输出包含ID，NAME和CALORIES列，但我不确定'如何'。我希望id＃自动填充，但是当我尝试在Oracle上找到的东西时，它无效。如何让线条看起来分开一切？
这是我的代码：
package edu.umsl.java3816.foodItem;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class FoodItemTable {
Connection fit = null;
public static void main(String[] args) {
String createTableSQL = "create table FOOD_ITEM(ID INTEGER,NAME VARCHAR(256),CALORIES INTEGER)";
String insertTableSQL = "INSERT INTO FOOD_ITEM(ID,NAME,CALORIES) VALUES('1','hamburger','550')";
String selectSQLStatement = "SELECT * FROM FOOD_ITEM";
FoodItemTable fit = new FoodItemTable();
try {
fit.getConnection();
fit.createTable(createTableSQL);
fit.insertSQL(insertTableSQL);
fit.selectSQL(selectSQLStatement);
fit.shutdownDB();
} catch (Exception e) {
e.printStackTrace();
}
}
public void getConnection() throws Exception {
Class.forName("org.hsqldb.jdbcDriver");
fit = DriverManager.getConnection("jdbc:hsqldb:mem", "sa", // username
"");
}
public void createTable(String sqlStatement) {
Statement statement = null;
try {
statement = fit.createStatement();
int i = statement.executeUpdate(sqlStatement);
if (i == -1) {
System.out.println("Error: " + sqlStatement);
}
} catch (SQLException e) {
e.printStackTrace();
}
}
public void insertSQL(String insertSQLStatement) {
Statement statement = null;
try {
statement = fit.createStatement();
int i = statement.executeUpdate(insertSQLStatement);
if (i == -1) {
System.out.println("Error: " + insertSQLStatement);
}
} catch (SQLException e) {
e.printStackTrace();
}
}
public void selectSQL(String selectSQLStatement) {
Statement statement = null;
try {
statement = fit.createStatement();
ResultSet rs = statement.executeQuery(selectSQLStatement);
while (rs.next()) {
System.out.println(rs.getInt("ID"));
System.out.println(rs.getString("NAME"));
System.out.println(rs.getInt("CALORIES"));
}
} catch (SQLException e) {
e.printStackTrace();
}
}
public void shutdownDB() {
try {
fit.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
答案 0 :(得分：1)
看起来像，就像您希望在控制台窗口中以有序的方式显示查询结果（至少在某种程度上）。
您可以使用java方法执行此操作，但首先需要将返回的查询结果集放入二维（2D）数组中。以下是您可以实现此目标的方法（利用您当前的 selectSQL（） 方法）：
public void selectSQL(String selectSQLStatement) {
PreparedStatement statement;
int resultSetCount = 0;
String rowCountSQL = "SELECT COUNT(*) AS rCount FROM FOOD_ITEM;";
try {
//Get the number of records within that will be
//retrieved from your query...
statement = fit.prepareStatement(rowCountSQL);
ResultSet rs = statement.executeQuery();
while (rs.next()) { resultSetCount = rs.getInt("rCount"); }
// Are there records to display?
if (resultSetCount == 0) {
// No there isn't
System.out.println("There are NO Records to display!");
return;
}
// Yes there is so let's declare our 2D Object Array...
Object[][] queriedRecords = new Object[resultSetCount][3];
// And now fill the array...
statement = fit.prepareStatement(selectSQLStatement);
rs = statement.executeQuery();
int counter = 0;
while (rs.next()) {
queriedRecords[counter][0] = rs.getInt("ID");
queriedRecords[counter][1] = rs.getString("NAME");
queriedRecords[counter][2] = rs.getInt("CALORIES");
counter++;
}
// Display the retrieved records in Console window...
// The table header names to be used when printed
String[] tableHeader = { "ID", "NAME", "CALORIES" };
consolePrintTable(tableHeader, queriedRecords, 2, false, true);
} catch (SQLException e) { e.printStackTrace(); }
}
您会注意到此方法的底部是对另一个名为 consolePrintTable（） 的方法的调用。此方法将检索到的数据显示到控制台。阅读我用这种方法提供的JavaDoc。这是方法代码：
/**
* This method will take the supplied data and print a table to console in a particular
* spaced format.<br><br>
*
* <b>Example Usage:</b><pre>
*
* final Object[][] table = new Object[4][];
* table[0] = new Object[] { "foo", "bar", "baz", "bar2", "foo2", "baz2" };
* table[1] = new Object[] { "bar2", "foo2", "baz2", "bar2", "foo2", "baz2" };
* table[2] = new Object[] { "baz3", "bar3", "foo3", "bar2", "foo2", "baz2" };
* table[3] = new Object[] { "foo4", "bar4", "baz4", "bar2", "foo2", "baz2" };
*
* String[] h = {"Header 1", "Header 2", "Header 3", "Header 4", "Header 5", "Header 6"};
* consolePrintTable(h, table, 4, false, true);
*
* // Output will be:
*
* --------------------------------------------------------------------
* Header 1 Header 2 Header 3 Header 4 Header 5 Header 6
* --------------------------------------------------------------------
* foo bar baz bar2 foo2 baz2
* bar2 foo2 baz2 bar2 foo2 baz2
* baz3 bar3 foo3 bar2 foo2 baz2
* foo4 bar4 baz4 bar2 foo2 baz2</pre>
*
* @param headerData (1D String Array) Column (header) titles for the table.
* If no Header is desired then supply <b>null</b><br>
*
* @param tableData (2D Object Array) The table data to display.<br>
*
* @param spacesBetweenCells (Integer) The table that will be printed is always
* spaced apart from one another based on the widest cell detected within both
* supplied header data or the 2D Object Array data. This parameter allows you
* add additional spacing between each column.<br>
*
* @param options (optional - Boolean) ...<pre>
*
* rightAlignment - (Default is false) If boolean true is supplied
* theTable is displayed as right justified. Boolean
* false make the table display as left justified.
*
* applyHeaderLines - (Default is true) By default lines are applied to
* the table so as to separate the header from table
* data. If false is supplied then header lines are
* not displayed. This option only applies if a Header
* 1D String Array is supplied (not null).
*
* </pre><br>
*/
public static void consolePrintTable(String[] headerData, Object[][] tableData, int spacesBetweenCells, boolean... options) {
if (tableData.length == 0) { return; }
boolean alignRight = false; // Default is Left Alignment
boolean addHeaderLines = true;
if(options.length > 0) {
if (options.length >= 1) { alignRight = options[0]; }
if (options.length == 2) { addHeaderLines = options[1]; }
}
// Get the widest Cell needed so that all the
// table cells will be the same when printed.
int widestCell = 0;
for (Object[] tableData1 : tableData) {
for (int j = 0; j < tableData[0].length; j++) {
int l = tableData1[j].toString().length();
if (l > widestCell) { widestCell = l; }
}
}
//Now check for the widest in header (if any)
if (headerData != null && headerData.length > 0) {
for(int i = 0; i < headerData.length; i++) {
if (headerData[i].length() > widestCell) {
widestCell = headerData[i].length();
}
}
}
widestCell = (widestCell + spacesBetweenCells);
// -------------------------------------------
int columns = tableData[0].length;
String format = "", alignStrg = "-";
if (alignRight) { alignStrg = ""; }
for (int i = 1; i <= columns; i++) {
format+= "%" + alignStrg + String.valueOf(widestCell) + "s";
}
format+= "\n";
//Print The Header (if any)...
if (headerData != null && headerData.length > 0) {
int charCount = columns*widestCell;
if (!alignRight) { charCount = ((columns*widestCell) - spacesBetweenCells);}
String gridline = "\n" + String.join("", Collections.nCopies(charCount, "-"));
if (addHeaderLines) { System.out.println(gridline); }
for(int i = 0; i < headerData.length; i++) {
System.out.printf("%" + alignStrg + String.valueOf(widestCell) + "s", headerData[i]);
}
if (addHeaderLines) { System.out.println(gridline); }
else { System.out.println(""); }
}
// Display the Table data...
for (final Object[] row : tableData) {
System.out.format(format, row);
}
}
答案 1 :(得分：0)
如果要在前端显示ID，卡路里和名称的数据（HTML），可以使用表格。一个简单的例子是：
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<table>
<tr>
<th>ID</th>
<th>NAME</th>
<th>Calories</th>
</tr>
<tr>
<td>You set the data here</td>
<td>..</td>
<td>..</td>
</tr>
<tr>
<td>..</td>
<td>..</td>
<td>..</td>
</tr>
</table>
</body>
</html>