Spring学习总结二——SpringIOC容器二

一：指定bean的依赖关系

例如examplebean对象依赖examplebean1对象，那么在创建examplebean对象之前就

需要先创建examplebean1对象。

1：创建Examplebean1类：

 /**
  *
  */
 package com.hlcui.dao;

 /**
  * @author Administrator
  *
  */
 public class ExampleBean1 {
     public ExampleBean1() {
         System.out.println("实例化ExampleBean1...");
     }
 }

2：在spring容器配置文件中配置ExampleBean1对象，并且指定bean的依赖关系

depends-on="ExampleBean1"

 <!-- 实例化ExampleBean对象 -->
     <bean id="exampleBean" class="com.hlcui.dao.ExampleBean" lazy-init="true"
     init-method="init" destroy-method="destroy" scope="singleton" depends-on="ExampleBean1"></bean>

     <!-- 实例化ExampleBean1对象 -->
     <bean id="ExampleBean1" class="com.hlcui.dao.ExampleBean1"
         lazy-init="true"></bean>

3：运行测试方法：

 @Test
     /**测试bean的依赖关系*/
     public void testNewExampleBean() {
         ApplicationContext ac = getApplicationContext();
         ExampleBean eb1 = ac.getBean("exampleBean", ExampleBean.class);
         System.out.println(eb1);
     }

通过结果可以看出先实例化依赖对象，再创建对象。

二：spring实现setter注入到jdbcDatasource数据库连接参数

1：导入jar包，在spring原有的支持包的基础上导入，oracle数据库的驱动包

2：创建JDBCDataSource类

 /**
  *
  */
 package com.hlcui.dao;

 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;

 /**
  * @author Administrator
  *
  */
 public class JDBCDataSource {

     private String driverClass;

     private String url;

     private String username;

     private String password;

     public String getDriverClass() {
         return driverClass;
     }

     public void setDriverClass(String driverClass) {
         try {
             Class.forName(driverClass); // 注册数据库驱动
             this.driverClass = driverClass;
         } catch (ClassNotFoundException e) {
             e.printStackTrace();
         }

     }

     public String getUrl() {
         return url;
     }

     public void setUrl(String url) {
         this.url = url;
     }

     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;
     }

     // 获取数据库连接
     public Connection getConn() throws SQLException {
         return DriverManager.getConnection(url, username, password);
     }

     // 关闭数据库连接
     public void closeConn(Connection conn) {
         if (null != conn) {
             try {
                 conn.close();
             } catch (SQLException e) {
                 e.printStackTrace();
             }
         }
     }
 }

3：配置bean对象

核心代码如下：

 <!-- 配置jdbc数据源 -->
     <bean id="jdbcDatasource" class="com.hlcui.dao.JDBCDataSource">
         <property name="driverClass" value="oracle.jdbc.OracleDriver"></property>
         <property name="url" value="jdbc:oracle:thin:@localhost:1521:orcl"></property>
         <property name="username" value="system"></property>
         <property name="password" value="orcl"></property>
     </bean>

4：测试方法以及运行结果

 @Test
     /**测试获取jdbc连接*/
     public void testJdbcConnection() {
         try {
             ApplicationContext ac = getApplicationContext();
             JDBCDataSource ds = ac.getBean("jdbcDatasource",
                     JDBCDataSource.class);
             System.out.println(ds.getConn());
         } catch (Exception e) {
             e.printStackTrace();
         }

     }

从运行结果可以看出，得到了jdbc连接对象。

三：spring实现构造器注入参数

1：创建业务实体类对象User

 /**
  *
  */
 package com.hlcui.dto;

 /**
  * @author Administrator
  *
  */
 public class User {
     private int id;
     private String name;
     private String pwd;
     private String phone;
     public User(int id, String name, String pwd, String phone) {
         super();
         this.id = id;
         this.name = name;
         this.pwd = pwd;
         this.phone = phone;
     }
     public User(String name, String pwd, String phone) {
         super();
         this.name = name;
         this.pwd = pwd;
         this.phone = phone;
     }
     public int getId() {
         return id;
     }
     public void setId(int id) {
         this.id = id;
     }
     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public String getPwd() {
         return pwd;
     }
     public void setPwd(String pwd) {
         this.pwd = pwd;
     }
     public String getPhone() {
         return phone;
     }
     public void setPhone(String phone) {
         this.phone = phone;
     }
     @Override
     public int hashCode() {
         final int prime = 31;
         int result = 1;
         result = prime * result + id;
         result = prime * result + ((name == null) ? 0 : name.hashCode());
         result = prime * result + ((phone == null) ? 0 : phone.hashCode());
         result = prime * result + ((pwd == null) ? 0 : pwd.hashCode());
         return result;
     }
     @Override
     public boolean equals(Object obj) {
         if (this == obj)
             return true;
         if (obj == null)
             return false;
         if (getClass() != obj.getClass())
             return false;
         User other = (User) obj;
         if (id != other.id)
             return false;
         if (name == null) {
             if (other.name != null)
                 return false;
         } else if (!name.equals(other.name))
             return false;
         if (phone == null) {
             if (other.phone != null)
                 return false;
         } else if (!phone.equals(other.phone))
             return false;
         if (pwd == null) {
             if (other.pwd != null)
                 return false;
         } else if (!pwd.equals(other.pwd))
             return false;
         return true;
     }
     @Override
     public String toString() {
         return "User [id=" + id + ", name=" + name + ", phone=" + phone
                 + ", pwd=" + pwd + "]";
     }

 }

2：创建oracle的sql脚本，并且执行sql

 --创建表users
 Create Table Users(
 Id Number(6,2),
 Name Varchar2(30),
 Pwd  Varchar2(50),
 Phone Varchar2(50),
 Primary Key(Id),
 constraint name unique(name)
 );

 --创建序列
 Create Sequence Seq_Users;

 --向表中插入数据
 Insert Into Users (Id,Name,Pwd,Phone) Values(Seq_Users.Nextval,'Tom','','');
 Insert Into Users (Id,Name,Pwd,Phone) Values(Seq_Users.Nextval,'Jack','','');
 Insert Into Users (Id,Name,Pwd,Phone) Values(Seq_Users.Nextval,'Lucy','','');
 commit;

3：创建UserDAO接口以及其实现类

 package com.hlcui.dao;

 import com.hlcui.dto.User;

 /**
  * @author Administrator
  *
  */
 public interface UserDAO {
     public User findByName(String name);
 }

 /**
  *
  */
 package com.hlcui.dao.impl;

 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;

 import com.hlcui.dao.JDBCDataSource;
 import com.hlcui.dao.UserDAO;
 import com.hlcui.dto.User;

 /**
  * @author Administrator
  *
  */
 public class OracleUserDAO implements UserDAO {

     private JDBCDataSource jdbcDataSource;

     public OracleUserDAO(JDBCDataSource jdbcDataSource) {
         this.jdbcDataSource = jdbcDataSource;
     }

     public User findByName(String name) {
         Connection conn = null;
         PreparedStatement prep = null;
         ResultSet rs = null;
         User user = null;
         try {
             conn = jdbcDataSource.getConn();
             String sql = "select id,pwd,phone from users where name=?";
             prep = conn.prepareStatement(sql);
             prep.setString(1, name);
             rs = prep.executeQuery();
             while (rs.next()) {
                 int id = rs.getInt("id");
                 String pwd = rs.getString("pwd");
                 String phone = rs.getString("phone");
                 user = new User(id, name, pwd, phone);
             }
         } catch (Exception e) {
             e.printStackTrace();
         }
         return user;
     }

 }

注：这里使用preparedstatement进行预编译，可以有效的防止sql注入，select * from tableName  where username='' and password = '' or 1=1,

这里的1=1是无论什么条件都会满足的，所以会登录进网站。经常使用ibatis框架的朋友对 where 1=1 and ... 比较熟悉，这里是为了防止后面的sql动态拼接

不满足条件造成 select * from tableName where 这种情况，这里区分一下。

4：在spring容器配置文件配置OracleUserDao的bean对象

 <!-- 配置jdbc数据源 -->
     <bean id="jdbcDatasource" class="com.hlcui.dao.JDBCDataSource">
         <property name="driverClass" value="oracle.jdbc.OracleDriver"></property>
         <property name="url" value="jdbc:oracle:thin:@localhost:1521:orcl"></property>
         <property name="username" value="system"></property>
         <property name="password" value="orcl"></property>
     </bean>

     <!-- 配置userDao对象 -->
     <bean id="userDao" class="com.hlcui.dao.impl.OracleUserDAO">
         <constructor-arg index="0" ref="jdbcDatasource"/>
     </bean>

constructor-arg元素代表构造器注入，index是参数的下表，0说明是第一个元素，如果有多个参数，可以使用如下格式：

 <constructor-arg index="0">
         <value>first parameter</value>
     </constructor-arg>
     <constructor-arg index="1">
         <value>second parameter</value>
     </constructor-arg>   

5：测试读取数据库中的user对象

 @Test
     /**测试从oracle数据库中读取数据*/
     public void testGetUser() {
         ApplicationContext ac = getApplicationContext();
         UserDAO dao = ac.getBean("userDao", OracleUserDAO.class);
         User user = dao.findByName("Tom");
         System.out.println(user);
     }

成功读取User对象！