本人小白，都是对着书上敲代码。实在是解决不了了-_-

package MysqlTest;

import java.io.FileInputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.Statement;
import java.util.Properties;

public class PreparedStatementTest {
private String driver;
private String url;
private String user;
private String password;
public void initParam(String paramFile)throws Exception
{
Properties props=new Properties();
props.load(new FileInputStream(paramFile));
driver=props.getProperty("driver");
url=props.getProperty("url");
user=props.getProperty("user");
password=props.getProperty("password");
}
public void insertUseStatement() throws Exception//这一个statement方法可以正常调用
{
long start=System.currentTimeMillis();
try(Connection conn=DriverManager.getConnection(url,user,password);
Statement stmt = conn.createStatement())
{
for(int i=0;i<100;i++)
{
stmt.executeUpdate("insert into student_table values("+i+",'cmd',"+i+")");
}
}
System.out.println("使用Statement费时："+(System.currentTimeMillis()-start));
}
public void insertUsePrepare() throws Exception//这一个出错了，提示表不存在。可是我是和上面那个一模一样的呀。怎么不存在呢
{
long start=System.currentTimeMillis();

try(Connection conn=DriverManager.getConnection(url,user,password);
PreparedStatement pstmt = conn.prepareStatement("insert into student_test values(250,?,1)"))
{
for(int i=0;i<100;i++)
{
pstmt.setString(1,"cmd");
pstmt.executeUpdate();
}
System.out.println(start);
}
System.out.println("使用PreparedStatement费时："+(System.currentTimeMillis()-start));
}
public static void main(String[] args) throws Exception
{
PreparedStatementTest pt=new PreparedStatementTest();
pt.initParam("db.properties");
pt.insertUseStatement();
pt.insertUsePrepare();
}
}

错误提示：

使用Statement费时：258
Exception in thread "main" com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table 'xianxian.student_test' doesn't exist
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
at com.mysql.jdbc.Util.getInstance(Util.java:408)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:943)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3973)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3909)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2527)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2680)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2494)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1858)
at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2079)
at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2013)
at com.mysql.jdbc.PreparedStatement.executeLargeUpdate(PreparedStatement.java:5104)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1998)
at MysqlTest.PreparedStatementTest.insertUsePrepare(PreparedStatementTest.java:48)
at MysqlTest.PreparedStatementTest.main(PreparedStatementTest.java:59)

好奇他怎么调出来xianxian.student_test表的。

我的表相关属性：