java之struts2之ajax

1.Ajax 技术在现有开发中使用非常多，大多是做管理类型系统。在servlet中可以使用ajax。在struts2中共还可以使用servlet的方式来实现ajax。

2.案例：用户名检查

public String checkName() throws IOException{
        HttpServletResponse resp = ServletActionContext.getResponse();
        if("siggy".equals(name)){
            resp.getWriter().print("true");
        }else{
            resp.getWriter().print("false");
        }
        //return Action.NONE;
        return null;
    }

3.使用struts2提供的插件来完成 ajax步骤

　　a) 导入相关 jar 包

asm-3.3.jar

asm-commons-3.3.jar

asm-tree-3.3.jar

commons-beanutils-1.8.0.jar

commons-collections-3.1.jar

commons-fileupload-1.2.2.jar

commons-io-2.0.1.jar

commons-lang-2.4.jar

commons-lang3-3.1.jar

commons-logging-1.1.1.jar

ezmorph-1.0.6.jar

freemarker-2.3.19.jar

jackson-core-asl-1.9.2.jar

jackson-mapper-asl-1.9.2.jar

javassist-3.11.0.GA.jar

json-lib-2.3-jdk15.jar

jstl-1.2.jar

log4j-1.2.17.jar

ognl-3.0.5.jar

struts2-core-2.3.4.jar

struts2-json-plugin-2.3.4.jar

xwork-core-2.3.4.jar

　　b) 编写Action

public class UserAction {
    private String name;
    private String result;
    public String checkName() throws IOException{
        HttpServletResponse resp = ServletActionContext.getResponse();
        if("siggy".equals(name)){
            resp.getWriter().print("true");
        }else{
            resp.getWriter().print("false");
        }
        //return Action.NONE;
        return null;
    }
    public String list(){
        System.out.println("list----------");
        List<User> list = new ArrayList<User>();
        list.add(new User("张三","男",33));
        list.add(new User("李四","男",23));
        list.add(new User("王五","男",13));
        try {
            result=JSONArray.fromObject(list).toString();
        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println(result);
        return Action.SUCCESS;
    }
    
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
    public String getResult() {
        return result;
    }
    public void setResult(String result) {
        this.result = result;
    }

}

　　c) 编写配置文件

<package name="default" extends="json-default" namespace="/">
        <action name="checkName" class="cn.sxt.action.UserAction" method="checkName">
        </action>
        <action name="list" class="cn.sxt.action.UserAction" method="list">
            <result type="json">
                <param name="root">result</param>
            </result>
        </action>
    </package>

4.另一种获取 json 的方式：

public class ListAction {
    private List<User> list;

    public String list(){
        list = new ArrayList<User>();
        list.add(new User("张三","男",33));
        list.add(new User("李四","男",23));
        list.add(new User("王五","男",13));
        return Action.SUCCESS;
    }
    public List<User> getList() {
        return list;
    }

    public void setList(List<User> list) {
        this.list = list;
    }
    
}

Struts.xml

<action name="listJson" class="cn.sxt.action.ListAction" method="list">
            <result type="json">
                <param name="root">list</param>
            </result>
        </action>

Jsp

<script type="text/javascript">
    $(function(){
        $("#btn").click(function(){
            $.post("listJson.action",function(data){
                var html="";
                for(var i=0;i<data.length;i++){
                    html+="<tr><td>"+data[i].name+
                    "</td><td>"+data[i].sex+
                    "</td><td>"+data[i].age+"</td></tr>";
                }
                $("#content").html(html);
            });
            
        });
    });
</script>
</head>
<body>
<button id="btn">获取数据</button>
    <table width="80%" align="center">
        <tr>
            <td>姓名</td>
            <td>性别</td>
            <td>年龄</td>
        </tr>
        <tbody id="content">
        </tbody>
    </table>
</body>