JNDI资源 How-To

package com.mycompany;
public class MyBean {
  private String foo = "Default Foo";
  public String getFoo() {
    return (this.foo);
  }
  public void setFoo(String foo) {
    this.foo = foo;
  }
  private int bar = 0;
  public int getBar() {
    return (this.bar);
  }
  public void setBar(int bar) {
    this.bar = bar;
  }
}

<resource-env-ref>
  <description>
    Object factory for MyBean instances.
  </description>
  <resource-env-ref-name>
    bean/MyBeanFactory
  </resource-env-ref-name>
  <resource-env-ref-type>
    com.mycompany.MyBean
  </resource-env-ref-type>
</resource-env-ref>

Context initCtx = new InitialContext()；
Context envCtx = (Context) initCtx.lookup("java:comp/env")；
MyBean bean = (MyBean) envCtx.lookup("bean/MyBeanFactory")；

writer.println("foo = " + bean.getFoo() + ", bar = " + "bean.getBar())
               bean.getBar())；

<Context ...>
  ...
  <Resource name="bean/MyBeanFactory" auth="Container"
            type="com.mycompany.MyBean"
            factory="org.apache.naming.factory.BeanFactory"
            bar="23"/>
  ...
</Context>

<?xml version="1.0" encoding="UTF-8"?>
<tomcat-users>
  <role rolename="tomcat"/>
  <role rolename="role1"/>
  <user username="tomcat" password="tomcat" roles="tomcat"/>
  <user username="both" password="tomcat" roles="tomcat,role1"/>
  <user username="role1" password="tomcat" roles="role1"/>
</tomcat-users>

<Resource name="UserDatabase"
          auth="Container"
          type="org.apache.catalina.UserDatabase"
          description="User database that can be updated and saved"
          factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
          pathname="conf/tomcat-users.xml"
          readonly="false" />

create table users (
  user_name         varchar(32) not null primary key,
  user_pass         varchar(64) not null,
  user_fullname     varchar(128)
  -- Add more attributes as needed
);

create table roles (
  role_name         varchar(32) not null primary key,
  role_description  varchar(128)
);

create table groups (
  group_name        varchar(32) not null primary key,
  group_description varchar(128)
);

create table user_roles (
  user_name         varchar(32) references users(user_name),
  role_name         varchar(32) references roles(role_name),
  primary key (user_name, role_name)
);

create table user_groups (
  user_name         varchar(32) references users(user_name),
  group_name        varchar(32) references groups(group_name),
  primary key (user_name, group_name)
);

create table group_roles (
  group_name        varchar(32) references groups(group_name),
  role_name         varchar(32) references roles(role_name),
  primary key (group_name, role_name)
);

create table users (
  user_name         varchar(32) not null primary key,
  user_pass         varchar(64) not null,
  -- Add more attributes as needed
);

create table user_roles (
  user_name         varchar(32),
  role_name         varchar(32),
  primary key (user_name, role_name)
);

<Resource name="UserDatabase" auth="Container"
              type="org.apache.catalina.UserDatabase"
              description="User database that can be updated and saved"
              factory="org.apache.catalina.users.DataSourceUserDatabaseFactory"
              dataSourceName="jdbc/authority" readonly="false"
              userTable="users" userNameCol="user_name" userCredCol="user_pass"
              userRoleTable="user_roles" roleNameCol="role_name"
              roleTable="roles" groupTable="groups" userGroupTable="user_groups"
              groupRoleTable="group_roles" groupNameCol="group_name" />

<resource-ref>
  <description>
    Resource reference to a factory for jakarta.mail.Session
    instances that may be used for sending electronic mail
    messages, preconfigured to connect to the appropriate
    SMTP server.
  </description>
  <res-ref-name>
    mail/Session
  </res-ref-name>
  <res-type>
    jakarta.mail.Session
  </res-type>
  <res-auth>
    Container
  </res-auth>
</resource-ref>

Context initCtx = new InitialContext();
Context envCtx = (Context) initCtx.lookup("java:comp/env");
Session session = (Session) envCtx.lookup("mail/Session");

Message message = new MimeMessage(session);
message.setFrom(new InternetAddress(request.getParameter("from")));
InternetAddress to[] = new InternetAddress[1];
to[0] = new InternetAddress(request.getParameter("to"));
message.setRecipients(Message.RecipientType.TO, to);
message.setSubject(request.getParameter("subject"));
message.setContent(request.getParameter("content"), "text/plain");
Transport.send(message);

<Context ...>
  ...
  <Resource name="mail/Session" auth="Container"
            type="jakarta.mail.Session"
            mail.smtp.host="localhost"/>
  ...
</Context>

<resource-ref>
  <description>
    Resource reference to a factory for java.sql.Connection
    instances that may be used for talking to a particular
    database that is configured in the <Context>
    configuration for the web application.
  </description>
  <res-ref-name>
    jdbc/EmployeeDB
  </res-ref-name>
  <res-type>
    javax.sql.DataSource
  </res-type>
  <res-auth>
    Container
  </res-auth>
</resource-ref>

Context initCtx = new InitialContext();
Context envCtx = (Context) initCtx.lookup("java:comp/env");
DataSource ds = (DataSource)
  envCtx.lookup("jdbc/EmployeeDB");

Connection conn = ds.getConnection();
... use this connection to access the database ...
conn.close();

<Context ...>
  ...
  <Resource name="jdbc/EmployeeDB"
            auth="Container"
            type="javax.sql.DataSource"
            username="dbusername"
            password="dbpassword"
            driverClassName="org.hsql.jdbcDriver"
            url="jdbc:HypersonicSQL:database"
            maxTotal="8"
            maxIdle="4"/>
  ...
</Context>

<resource-env-ref>
  <description>
    Object factory for MyBean instances.
  </description>
  <resource-env-ref-name>
    bean/MyBeanFactory
  </resource-env-ref-name>
  <resource-env-ref-type>
    com.mycompany.MyBean
  </resource-env-ref-type>
</resource-env-ref>

Context initCtx = new InitialContext();
Context envCtx = (Context) initCtx.lookup("java:comp/env");
MyBean bean = (MyBean) envCtx.lookup("bean/MyBeanFactory");

writer.println("foo = " + bean.getFoo() + ", bar = " +
               bean.getBar());

<Context ...>
  ...
  <Resource name="bean/MyBeanFactory" auth="Container"
            type="com.mycompany.MyBean"
            factory="com.mycompany.MyBeanFactory"
            singleton="false"
            bar="23"/>
  ...
</Context>