Java学习路线-55：自定义JSP标签

第 10 章 ： 自定义标签 编写步骤：

1. 标签处理类
2. 编写 tld 文件
3. taglib 导入 tld 文件

依赖

    javax.servlet
    javax.servlet-api
    4.0.1
    provided



    javax.servlet.jsp
    javax.servlet.jsp-api
    2.3.3
    provided

定义无内容标签

package com.pengshiyu.taglibs;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.SimpleTagSupport;
import java.io.IOException;

public class HelloTag extends SimpleTagSupport {
    @Override
    public void doTag() throws JspException, IOException {
        this.getJspContext().getOut().println("hello");
    }
}

声明

    1.0
    2.0
    Example TLD with Body

    
        Hello
        com.pengshiyu.taglibs.HelloTag
        empty
    

引入声明文件并使用标签

定义有内容标签

package com.pengshiyu.taglibs;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.SimpleTagSupport;
import java.io.IOException;

public class HelloTag extends SimpleTagSupport {
    @Override
    public void doTag() throws JspException, IOException {
        JspWriter out = this.getJspContext().getOut();
        out.write("******");
        this.getJspBody().invoke(out);
        out.write("******");
    }
}

你好

输出

****** 你好 ******

不再执行标签下面的内容

package com.pengshiyu.taglibs;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.SkipPageException;
import javax.servlet.jsp.tagext.SimpleTagSupport;
import java.io.IOException;

public class HelloTag extends SimpleTagSupport {
    @Override
    public void doTag() throws JspException, IOException {
        this.getJspContext().getOut().write("以下内容不显示");
        throw new SkipPageException();
    }
}

带有属性的标签

标签类

package com.pengshiyu.taglibs;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.SimpleTagSupport;
import java.io.IOException;

public class HelloTag extends SimpleTagSupport {


    private String name = "";

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public void doTag() throws JspException, IOException {
        this.getJspContext().getOut().write(this.name);

    }
}

tld 配置

    Hello
    com.pengshiyu.taglibs.HelloTag
    scriptless
    

        name

        true

        true
    

使用