freemarker处理空值

freemarker处理空值

1、设计思路

（1）封装学生类和课程类

（2）新建学生课程页面ftl文件

（3）创建测试方法

2、封装课程类

Course.java：

/**
 * @Title:Course.java
 * @Package:com.you.freemarker.model
 * @Description:课程封装类
 * @author:Youhaidong(游海东)
 * @date:2014-5-28 下午9:41:41
 * @version V1.0
 */
package com.you.freemarker.model;

/**
 * 类功能说明
 * 类修改者 修改日期
 * 修改说明
 * <p>Title:Course.java</p>
 * <p>Description:游海东个人开发</p>
 * <p>Copyright:Copyright(c)2013</p>
 * @author:游海东
 * @date:2014-5-28 下午9:41:41
 * @version V1.0
 */
public class Course
{
	/**
	 * 课程名
	 */
	private String courseName;

	/**
	 * @return the courseName
	 */
	public String getCourseName() {
		return courseName;
	}

	/**
	 * @param courseName the courseName to set
	 */
	public void setCourseName(String courseName) {
		this.courseName = courseName;
	}

	/**
	 * <p>Title:</p>
	 * <p>Description:有参构造函数</p>
	 * @param courseName
	 */
	public Course(String courseName) {
		super();
		this.courseName = courseName;
	}

	/**
	 * <p>Title:</p>
	 * <p>Description:无参构造函数</p>
	 */
	public Course() {
		super();
	}

}

3、封装学生类

Student.java：

/**
 * @Title:Student.java
 * @Package:com.you.freemarker.model
 * @Description:学生类
 * @author:Youhaidong(游海东)
 * @date:2014-5-26 下午11:41:05
 * @version V1.0
 */
package com.you.freemarker.model;

import java.io.Serializable;
import java.util.Date;

/**
 * 类功能说明
 * 类修改者 修改日期
 * 修改说明
 * <p>Title:Student.java</p>
 * <p>Description:游海东个人开发</p>
 * <p>Copyright:Copyright(c)2013</p>
 * @author:游海东
 * @date:2014-5-26 下午11:41:05
 * @version V1.0
 */
public class Student implements Serializable
{
	/**
	 * @Fields  serialVersionUID:序列化
	 */
	private static final long serialVersionUID = 1L;

	/**
	 * 学生姓名
	 */
	private String studentName;

	/**
	 * 学生性别
	 */
	private String studentSex;

	/**
	 * 学生年龄
	 */
	private int studentAge;

	/**
	 * 学生生日
	 */
	private Date studentBirthday;

	/**
	 * 学生地址
	 */
	private String studentAddr;

	/**
	 * QQ
	 */
	private long studentQQ;

	/**
	 * 课程
	 */
	private Course course;

	/**
	 * @return the studentName
	 */
	public String getStudentName() {
		return studentName;
	}

	/**
	 * @param studentName the studentName to set
	 */
	public void setStudentName(String studentName) {
		this.studentName = studentName;
	}

	/**
	 * @return the studentSex
	 */
	public String getStudentSex() {
		return studentSex;
	}

	/**
	 * @param studentSex the studentSex to set
	 */
	public void setStudentSex(String studentSex) {
		this.studentSex = studentSex;
	}

	/**
	 * @return the studentAge
	 */
	public int getStudentAge() {
		return studentAge;
	}

	/**
	 * @param studentAge the studentAge to set
	 */
	public void setStudentAge(int studentAge) {
		this.studentAge = studentAge;
	}

	/**
	 * @return the studentBirthday
	 */
	public Date getStudentBirthday() {
		return studentBirthday;
	}

	/**
	 * @param studentBirthday the studentBirthday to set
	 */
	public void setStudentBirthday(Date studentBirthday) {
		this.studentBirthday = studentBirthday;
	}

	/**
	 * @return the studentAddr
	 */
	public String getStudentAddr() {
		return studentAddr;
	}

	/**
	 * @param studentAddr the studentAddr to set
	 */
	public void setStudentAddr(String studentAddr) {
		this.studentAddr = studentAddr;
	}

	/**
	 * @return the studentQQ
	 */
	public long getStudentQQ() {
		return studentQQ;
	}

	/**
	 * @param studentQQ the studentQQ to set
	 */
	public void setStudentQQ(long studentQQ) {
		this.studentQQ = studentQQ;
	}

	/**
	 * <p>Title:</p>
	 * <p>Description:无参构造函数</p>
	 */
	public Student() {
		super();
	}

	/**
	 * <p>Title:</p>
	 * <p>Description:有参构造函数</p>
	 * @param studentName
	 * @param studentSex
	 * @param studentAge
	 * @param studentBirthday
	 * @param studentAddr
	 * @param studentQQ
	 */
	public Student(String studentName, String studentSex, int studentAge,
			Date studentBirthday, String studentAddr, long studentQQ) {
		super();
		this.studentName = studentName;
		this.studentSex = studentSex;
		this.studentAge = studentAge;
		this.studentBirthday = studentBirthday;
		this.studentAddr = studentAddr;
		this.studentQQ = studentQQ;
	}

	/**
	 * @return the course
	 */
	public Course getCourse() {
		return course;
	}

	/**
	 * @param course the course to set
	 */
	public void setCourse(Course course) {
		this.course = course;
	}

}

/**
 * @Title:Student.java
 * @Package:com.you.freemarker.model
 * @Description:学生类
 * @author:Youhaidong(游海东)
 * @date:2014-5-26 下午11:41:05
 * @version V1.0
 */
package com.you.freemarker.model;

import java.io.Serializable;
import java.util.Date;

/**
 * 类功能说明
 * 类修改者 修改日期
 * 修改说明
 * <p>Title:Student.java</p>
 * <p>Description:游海东个人开发</p>
 * <p>Copyright:Copyright(c)2013</p>
 * @author:游海东
 * @date:2014-5-26 下午11:41:05
 * @version V1.0
 */
public class Student implements Serializable
{
	/**
	 * @Fields  serialVersionUID:序列化
	 */
	private static final long serialVersionUID = 1L;

	/**
	 * 学生姓名
	 */
	private String studentName;

	/**
	 * 学生性别
	 */
	private String studentSex;

	/**
	 * 学生年龄
	 */
	private int studentAge;

	/**
	 * 学生生日
	 */
	private Date studentBirthday;

	/**
	 * 学生地址
	 */
	private String studentAddr;

	/**
	 * QQ
	 */
	private long studentQQ;

	/**
	 * 课程
	 */
	private Course course;

	/**
	 * @return the studentName
	 */
	public String getStudentName() {
		return studentName;
	}

	/**
	 * @param studentName the studentName to set
	 */
	public void setStudentName(String studentName) {
		this.studentName = studentName;
	}

	/**
	 * @return the studentSex
	 */
	public String getStudentSex() {
		return studentSex;
	}

	/**
	 * @param studentSex the studentSex to set
	 */
	public void setStudentSex(String studentSex) {
		this.studentSex = studentSex;
	}

	/**
	 * @return the studentAge
	 */
	public int getStudentAge() {
		return studentAge;
	}

	/**
	 * @param studentAge the studentAge to set
	 */
	public void setStudentAge(int studentAge) {
		this.studentAge = studentAge;
	}

	/**
	 * @return the studentBirthday
	 */
	public Date getStudentBirthday() {
		return studentBirthday;
	}

	/**
	 * @param studentBirthday the studentBirthday to set
	 */
	public void setStudentBirthday(Date studentBirthday) {
		this.studentBirthday = studentBirthday;
	}

	/**
	 * @return the studentAddr
	 */
	public String getStudentAddr() {
		return studentAddr;
	}

	/**
	 * @param studentAddr the studentAddr to set
	 */
	public void setStudentAddr(String studentAddr) {
		this.studentAddr = studentAddr;
	}

	/**
	 * @return the studentQQ
	 */
	public long getStudentQQ() {
		return studentQQ;
	}

	/**
	 * @param studentQQ the studentQQ to set
	 */
	public void setStudentQQ(long studentQQ) {
		this.studentQQ = studentQQ;
	}

	/**
	 * <p>Title:</p>
	 * <p>Description:无参构造函数</p>
	 */
	public Student() {
		super();
	}

	/**
	 * <p>Title:</p>
	 * <p>Description:有参构造函数</p>
	 * @param studentName
	 * @param studentSex
	 * @param studentAge
	 * @param studentBirthday
	 * @param studentAddr
	 * @param studentQQ
	 */
	public Student(String studentName, String studentSex, int studentAge,
			Date studentBirthday, String studentAddr, long studentQQ) {
		super();
		this.studentName = studentName;
		this.studentSex = studentSex;
		this.studentAge = studentAge;
		this.studentBirthday = studentBirthday;
		this.studentAddr = studentAddr;
		this.studentQQ = studentQQ;
	}

	/**
	 * @return the course
	 */
	public Course getCourse() {
		return course;
	}

	/**
	 * @param course the course to set
	 */
	public void setCourse(Course course) {
		this.course = course;
	}

}

4、新建学生课程页面ftl文件

course.ftl：

<html>
  <head>
    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
    <title>学生信息</title>

  </head>

  <body>
    	姓名：${student.studentName}
     	性别：${student.studentSex}
     	年龄：${student.studentAge}
     	生日：${(student.studentBirthday)?string("yyyy-MM-dd")}
    	地址：${student.studentAddr}
  		QQ：${student.studentQQ}
                  课程：${student.course!}
  </body>
</html>

5、创建测试方法

/**
	 * 测试freemarker处理空值
	 * @Title:testCourse
	 * @Description:
	 * @param:
	 * @return: void
	 * @throws
	 */
	@Test
	public void testCourse()
	{
		//freemarker不会处理空值
		root.put("student", new Student("张三丰","男",16,new Date(1988-12-12),"湖北省武汉市武昌洪山区",78451214));
		studentPrint("course.ftl");
	}

6、运行结果

<html>
  <head>
    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
    <title>学生信息</title>

  </head>

  <body>
    	姓名：张三丰
     	性别：男
     	年龄：16
     	生日：1970-01-01
    	地址：湖北省武汉市武昌洪山区
  		QQ：78,451,214
                  课程：
  </body>
</html>