Question

各位来看一下这段java连接数据库的代码

import java.sql.*;
public class test() throws SQLException
{
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
String driver ="com.microsoft.jdbc.sqlserver.SQLServerDriver";
String url ="jdbc:microsoft.sqlserver://localhost:1433;DatabaseName=Restaurant";
String user ="user";
String pwd ="user";
sql ="select name,password from operator;";
public static void main(String [] args)
{
Class.forName(driver);
System.out.println("加载驱动成功！");
conn = DriverManager.getConnection(url,user,pwd);
System.out.println("连接数据库成功！");
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
while(rs.next())
{
System.out.println("------记录-------");
System.out.println("姓 名: "+rs.getString("name"));
System.out.println("密 码: "+rs.getString("password"));
}
}
}

编译时报错说：
public class test() throws SQLException
^
test.java:28: 需要 '}'
^
怎么回事啊？
sql语句多打了一个分号，实际上是没有的

报错说的是：

test.java:2: 需要 '{'
public class test() throws SQLException
^
test.java:28: 需要 '}'

2 错误

Answer 1

你这段程序错误太多了

1）
public class test() throws SQLException
test是类，不是方法，不要用()，不能抛出异常
改为
public class test

2）sql ="select name,password from operator;";
sql变量没有声明，改为
String sql ="select name,password from operator;";

3) main方法是静态方法，里面不能使用conn等非静态变量。
改为新定义一个方法，
然后再main中创建一个test对象，在调用该方法

4)因为除了SQLException，语句Class.forName(driver);还会抛出其它异常，所以在方法直接使用catch处理所有的异常。

修改后
import java.sql.*;
public class test
{
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
String driver ="com.microsoft.jdbc.sqlserver.SQLServerDriver";
String url ="jdbc:microsoft.sqlserver://localhost:1433;DatabaseName=Restaurant";
String user ="user";
String pwd ="user";
String sql ="select name,password from operator;";

public void doTest() {
try{
Class.forName(driver);
System.out.println("加载驱动成功！");
conn = DriverManager.getConnection(url,user,pwd);
System.out.println("连接数据库成功！");
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
while(rs.next())
{
System.out.println("------记录-------");
System.out.println("姓 名: "+rs.getString("name"));
System.out.println("密 码: "+rs.getString("password"));
}
}catch(Exception e){
e.printStackTrace();
}
}

public static void main(String [] args)
{
new test().doTest();
}
}

Answer 2

import java.sql.*;
public class test
{
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
String driver ="com.microsoft.jdbc.sqlserver.SQLServerDriver";
String url ="jdbc:microsoft.sqlserver://localhost:1433;DatabaseName=Restaurant";
String user ="user";
String pwd ="user";
String sql ="select name,password from operator;";

public void doTest() {
try{
Class.forName(driver);
System.out.println("加载驱动成功！");
conn = DriverManager.getConnection(url,user,pwd);
System.out.println("连接数据库成功！");
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
while(rs.next())
{
System.out.println("------记录-------");
System.out.println("姓 名: "+rs.getString("name"));
System.out.println("密 码: "+rs.getString("password"));
}
}catch(Exception e){
e.printStackTrace();
}
}

public static void main(String [] args)
{
new test().doTest();
}
}