一，常用坐标导入
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<!-- servlet-->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>
<!-- mysql-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.25</version>
</dependency>
<!-- fastjson-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.62</version>
</dependency>
<!-- druid数据库连接池-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.12</version>
</dependency>
<!--jdbcTemplate-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.1.2.RELEASE</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>4.1.2.RELEASE</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>4.1.2.RELEASE</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>4.1.2.RELEASE</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
<version>1.1.1</version>
<scope>compile</scope>
</dependency>
<!--beanUtils用于封装表单数据-->
<dependency>
<groupId>commons-beanutils</groupId>
<artifactId>commons-beanutils</artifactId>
<version>1.9.2</version>
<scope>compile</scope>
</dependency>
</dependencies>二，常用的配置类
★jdbc.properties
user=root
password=111111
url=jdbc:mysql:///mysql?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=UTC
driverClass=com.mysql.cj.jdbc.Driver()三，常用的工具类
★JDBCUtils
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
/*
1. 声明静态数据源成员变量
2. 创建连接池对象
3. 定义公有的得到数据源的方法
4. 定义得到连接对象的方法
5. 定义关闭资源的方法
*/
public class JDBCUtils {
// 1. 声明静态数据源成员变量
private static DataSource ds;
// 2. 创建连接池对象
static {
// 加载配置文件中的数据
InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("jdbc.properties");
Properties pp = new Properties();
try {
pp.load(is);
// 创建连接池，使用配置文件中的参数
ds = DruidDataSourceFactory.createDataSource(pp);
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
// 3. 定义公有的得到数据源的方法
public static DataSource getDataSource() {
return ds;
}
// 4. 定义得到连接对象的方法
public static Connection getConnection() throws SQLException {
return ds.getConnection();
}
// 5.定义关闭资源的方法
public static void close(Connection conn, Statement stmt, ResultSet rs) {
if (rs != null) {
try {
rs.close();
} catch (SQLException e) {}
}
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {}
}
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {}
}
}
// 6.重载关闭方法
public static void close(Connection conn, Statement stmt) {
close(conn, stmt, null);
}
}★BeanUtil
导入对应的坐标即可
<!--beanUtils用于封装表单数据-->
<dependency>
<groupId>commons-beanutils</groupId>
<artifactId>commons-beanutils</artifactId>
<version>1.9.2</version>
<scope>compile</scope>
</dependency>
</dependencies>?作用：用于在servlet层对前端的数据封装成为对象，常用于表单数据，先使用getParameterMap获取Map集合，再通过BeanUtil进行封装成对象
eg：
四，BaseServlet
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
public class BaseServlet extends HttpServlet {
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//1.获取请求路径
String uri = req.getRequestURI();
//2.获取最后一段路径，方法名
int index = uri.lastIndexOf('/');
String methodName = uri.substring(index + 1);
//3.1获取BrandServlet，UserServlet字节码对象class
//this指向BrandServlet，UserServlet...
Class<? extends BaseServlet> cls = this.getClass();
//3.2获取方法Method对象
try {
Method method = cls.getMethod(methodName, HttpServletRequest.class,HttpServletResponse.class);
//3.3执行方法
method.invoke(this,req,resp);
} catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
e.printStackTrace();
}
}
}五，常用的Bean对象
★ResultInfo
作用：用于前后端交互，主要封装数据放回，错误信息和判断方法是否执行成功
import java.io.Serializable;
public class ResultInfo implements Serializable {
private boolean flag;
private Object data;
private String errorMsg;
public ResultInfo() {
}
public ResultInfo(boolean flag, Object data, String errorMsg) {
this.flag = flag;
this.data = data;
this.errorMsg = errorMsg;
}
public boolean isFlag() {
return flag;
}
public void setFlag(boolean flag) {
this.flag = flag;
}
public Object getData() {
return data;
}
public void setData(Object data) {
this.data = data;
}
public String getErrorMsg() {
return errorMsg;
}
public void setErrorMsg(String errorMsg) {
this.errorMsg = errorMsg;
}
}★pageBean
作用：用于数据分页展示
import java.util.List;
public class PageBean<T> {
private int totalCount;//总记录数
private int totalPage;//总页数
private int currentPage;//当前页码
private int pageSize;//每页显示的条数
private List<T> list;//每页显示的数据集合
public int getTotalCount() {
return totalCount;
}
public void setTotalCount(int totalCount) {
this.totalCount = totalCount;
}
public int getTotalPage() {
return totalPage;
}
public void setTotalPage(int totalPage) {
this.totalPage = totalPage;
}
public int getCurrentPage() {
return currentPage;
}
public void setCurrentPage(int currentPage) {
this.currentPage = currentPage;
}
public int getPageSize() {
return pageSize;
}
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
public List<T> getList() {
return list;
}
public void setList(List<T> list) {
this.list = list;
}
}六，思路总结
1.dao用于操作小方法，service用于调用多个dao方法来执行一个大的业务方法，servlet用于前后端的数据处理和交互。