jsp判断语句_Java的web展现层JSP的JSTL标签详细总结

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JSP的标签

一、输出数据标签

(1)bean类

package com;

public class User {

private String name;

private String sid;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getSid() {

return sid;

}

public void setSid(String sid) {

this.sid = sid;

}

}

(2)servlet控制

package com;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class DemoServlet extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

User user=new User();

//注意要加set方法

user.setName("zhangsan");

request.setAttribute("user", user);

request.getRequestDispatcher("/test.jsp").forward(request, response);

}

}

(3)test.jsp页面

二、循环标签

循环标签比较复杂

【1】循环list数据，并且list里面数据为基本数据类型

(1)servlet

package com;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class DemoServlet extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

List list=new ArrayList();

list.add("aaa");

list.add("bbb");

list.add("ccc");

request.setAttribute("list", list);

request.getRequestDispatcher("/test.jsp").forward(request, response);

}

}

(2)test.jsp页面

${id.index }

【2】循环list数据，并且list里面数据为引用数据类型

(1)User实体类

package com;

public class User {

private String name;

private String sid;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getSid() {

return sid;

}

public void setSid(String sid) {

this.sid = sid;

}

}

(2)servlet

package com;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class DemoServlet extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

List list=new ArrayList();

User user1=new User();

user1.setName("zhaoyan1");

User user2=new User();

user2.setName("zhaoyan2");

User user3=new User();

user3.setName("zhaoyan3");

list.add(user1);

list.add(user2);

list.add(user3);

request.setAttribute("list", list);

request.getRequestDispatcher("/test.jsp").forward(request, response);

}

}

(3)test.jsp页面

${id.index }

三、页面之间数据传递

(1)index.jsp页面

测试标签

提交

(2)deal.jsp页面

测试标签

传递的参数：${param.user}

四、if判断语句

(1)User.java实体bean

package com;

public class User {

private String name;

private String sid;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getSid() {

return sid;

}

public void setSid(String sid) {

this.sid = sid;

}

}

(2)servlet

package com;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class DemoServlet extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

List list=new ArrayList();

User user1=new User();

user1.setName("zhaoyan1");

User user2=new User();

user2.setName("zhaoyan2");

User user3=new User();

user3.setName("zhaoyan3");

list.add(user1);

list.add(user2);

list.add(user3);

request.setAttribute("list", list);

request.getRequestDispatcher("/test.jsp").forward(request, response);

}

}

(3)test.jsp文件

${id.index } 赵燕222！！

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