conn.java
package javafan;
import java.sql.*;
import java.util.*;
public class conns {
Connection conn=null;
ResultSet rs;
String user ="sa";
String password ="123";
String sql;
String url ="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=guestbook";
public conns()
{
try{
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();
System.out.println("数据库连接成功!"); }
catch(Exception e)
{
e.printStackTrace();
System.out.println("数据库连接失败");
}
}
public List executeQuery(String sql)
{
conn = DriverManager.getConnection(url, user, password);
Statement stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
List results = new ArrayList();
while (rs.next())
{
Admin beans = new Admin();
beans.setUserName(rs.getString("username"));
beans.setPassword(rs.getString("password"));
results.add(beans);
}
stmt.close();
conn.close();
System.out.println(" <br>数据库表打开!");
return results;
} }Admin.java
package javafan;public class Admin {
private String userName; private String password; public String getUserName() {
return userName;
} public void setUserName(String userName) {
this.userName = userName;
} public String getPassword() {
return password;
} public void setPassword(String password) {
this.password = password;
}
}报错内容:vafan\conns.java:28: unreported exception java.sql.SQLException; must be caugh
t or declared to be thrown
conn = DriverManager.getConnection(url, user, password);
^
javafan\conns.java:29: unreported exception java.sql.SQLException; must be caugh
t or declared to be thrown
Statement stmt = conn.createStatement();
^
javafan\conns.java:30: unreported exception java.sql.SQLException; must be caugh
t or declared to be thrown
rs = stmt.executeQuery(sql);
^
javafan\conns.java:32: unreported exception java.sql.SQLException; must be caugh
t or declared to be thrown
while (rs.next())
^
javafan\conns.java:35: unreported exception java.sql.SQLException; must be caugh
t or declared to be thrown
beans.setUserName(rs.getString("username"));
^
javafan\conns.java:36: unreported exception java.sql.SQLException; must be caugh
t or declared to be thrown
beans.setPassword(rs.getString("password"));
^
javafan\conns.java:39: unreported exception java.sql.SQLException; must be caugh
t or declared to be thrown
stmt.close();
^
javafan\conns.java:40: unreported exception java.sql.SQLException; must be caugh
t or declared to be thrown
conn.close();
^
package javafan;
import java.sql.*;
import java.util.*;
public class conns {
Connection conn=null;
ResultSet rs;
String user ="sa";
String password ="123";
String sql;
String url ="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=guestbook";
public conns()
{
try{
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();
System.out.println("数据库连接成功!"); }
catch(Exception e)
{
e.printStackTrace();
System.out.println("数据库连接失败");
}
}
public List executeQuery(String sql)
{
conn = DriverManager.getConnection(url, user, password);
Statement stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
List results = new ArrayList();
while (rs.next())
{
Admin beans = new Admin();
beans.setUserName(rs.getString("username"));
beans.setPassword(rs.getString("password"));
results.add(beans);
}
stmt.close();
conn.close();
System.out.println(" <br>数据库表打开!");
return results;
} }Admin.java
package javafan;public class Admin {
private String userName; private String password; public String getUserName() {
return userName;
} public void setUserName(String userName) {
this.userName = userName;
} public String getPassword() {
return password;
} public void setPassword(String password) {
this.password = password;
}
}报错内容:vafan\conns.java:28: unreported exception java.sql.SQLException; must be caugh
t or declared to be thrown
conn = DriverManager.getConnection(url, user, password);
^
javafan\conns.java:29: unreported exception java.sql.SQLException; must be caugh
t or declared to be thrown
Statement stmt = conn.createStatement();
^
javafan\conns.java:30: unreported exception java.sql.SQLException; must be caugh
t or declared to be thrown
rs = stmt.executeQuery(sql);
^
javafan\conns.java:32: unreported exception java.sql.SQLException; must be caugh
t or declared to be thrown
while (rs.next())
^
javafan\conns.java:35: unreported exception java.sql.SQLException; must be caugh
t or declared to be thrown
beans.setUserName(rs.getString("username"));
^
javafan\conns.java:36: unreported exception java.sql.SQLException; must be caugh
t or declared to be thrown
beans.setPassword(rs.getString("password"));
^
javafan\conns.java:39: unreported exception java.sql.SQLException; must be caugh
t or declared to be thrown
stmt.close();
^
javafan\conns.java:40: unreported exception java.sql.SQLException; must be caugh
t or declared to be thrown
conn.close();
^
{
conn = DriverManager.getConnection(url, user, password);
Statement stmt = conn.createStatement();
rs = stmt.executeQuery(sql); 加上红色的那句话,或者把上面的三句加try{}catch(E e){}
must be caught or declared to be thrown
要能抛出异常
要你还是用记事本什么开发的话,,建议你要学开发工具了
那几个语句可能出现异常 需要捕获
我觉得还是你操作错误了,对于checked exception,必须捕获或者抛出。这个和打包不打包没关系啊。