import java.io.InputStream
时间: 2024-03-06 16:34:24 浏览: 6
public class MyClass {
public static void main(String[] args) {
// Create an input stream
InputStream inputStream = System.in;
// Read the input from the user
System.out.println("Enter your name: ");
try {
byte[] input = new byte[100];
int numBytesRead = inputStream.read(input);
String name = new String(input, 0, numBytesRead);
System.out.println("Hello, " + name + "!");
} catch (Exception e) {
System.out.println("Error reading input: " + e.getMessage());
}
}
}
相关问题
package day0608.utils; import com.alibaba.druid.pool.DruidDataSource; import com.alibaba.druid.pool.DruidDataSourceFactory; import javax.sql.DataSource; import java.io.IOException; import java.io.InputStream; import java.util.Properties; /** * 连接池工具类
这是一个连接池工具类的代码,它使用阿里巴巴的Druid连接池来实现数据库连接的复用,避免频繁地创建和关闭数据库连接。通过读取配置文件中的数据库连接参数,创建Druid数据源,并通过数据源获取数据库连接。在使用完成后,需要将连接关闭并归还给连接池。以下是代码的详细解释:
1. 导入Druid相关的类和接口
```java
import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;
```
2. 创建连接池工具类
```java
public class ConnectionPoolUtil {
private static DataSource dataSource;
static {
try {
// 读取配置文件
InputStream inputStream = ConnectionPoolUtil.class.getClassLoader().getResourceAsStream("druid.properties");
Properties properties = new Properties();
properties.load(inputStream);
// 创建Druid数据源
dataSource = DruidDataSourceFactory.createDataSource(properties);
} catch (Exception e) {
e.printStackTrace();
}
}
// 获取数据库连接
public static Connection getConnection() throws SQLException {
return dataSource.getConnection();
}
// 关闭数据库连接
public static void closeConnection(Connection conn, PreparedStatement pstmt, ResultSet rs) {
try {
if (rs != null) {
rs.close();
}
if (pstmt != null) {
pstmt.close();
}
if (conn != null) {
conn.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
```
3. 使用连接池工具类
```java
public class MyDao {
public List<User> getAllUsers() {
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
List<User> userList = new ArrayList<>();
try {
// 获取数据库连接
conn = ConnectionPoolUtil.getConnection();
pstmt = conn.prepareStatement("SELECT * FROM user");
rs = pstmt.executeQuery();
// 处理查询结果
while (rs.next()) {
User user = new User();
user.setId(rs.getInt("id"));
user.setName(rs.getString("name"));
user.setAge(rs.getInt("age"));
userList.add(user);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
// 关闭数据库连接
ConnectionPoolUtil.closeConnection(conn, pstmt, rs);
}
return userList;
}
}
```
以上是连接池工具类的基本实现,可以在多线程环境下安全地使用。同时,Druid还提供了很多其他的功能,例如监控、防御SQL注入攻击等,可以根据实际需求进行配置和使用。
import com.tyhxzy.entity.User; import com.tyhxzy.mapper.UserMApper; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; import org.junit.Test; import sun.security.util.Resources; import java.io.InputStream; import java.util.List; public class mybatis { @Test public void chaxun(){ InputStream inputStream = Resources.getResourceAsSteream("mybatis-config.xml"); SqlSessionFactoryBuilder builder=new SqlSessionFactoryBuilder (); SqlSessionFactory sqlSessionFactory=builder.build ( inputStream ); SqlSession con=sqlSessionFactory.openSession (); UserMApper cc=con.getMapper ( UserMApper.class ); List<User> list=cc.findall (); for (User item:list){ System.out.println (item); } } }哪里错了
您的代码存在几个问题:
1. `Resources` 类在当前 Java 版本中已经被废弃,建议使用其他替代方案。
2. `SqlSessionFactoryBuilder` 类的 `build()` 方法需要传入一个 `Reader` 类型的参数,而您传入的是 `InputStream` 类型的参数,需要将其转换为 `Reader` 类型。
3. `mybatis-config.xml` 文件需要放置在类路径下,以便正确读取。
下面是修改后的代码示例:
```
import com.tyhxzy.entity.User;
import com.tyhxzy.mapper.UserMapper;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.nio.charset.StandardCharsets;
public class MyBatisTest {
@Test
public void test() throws IOException {
InputStream inputStream = getClass().getClassLoader().getResourceAsStream("mybatis-config.xml");
Reader reader = new java.io.InputStreamReader(inputStream, StandardCharsets.UTF_8);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
SqlSession sqlSession = sqlSessionFactory.openSession();
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
List<User> userList = userMapper.findAll();
for (User user : userList) {
System.out.println(user);
}
sqlSession.close();
}
}
```