vulcan

低頭做事,抬頭看路

:: 管理

41 Posts :: 7 Stories :: 28 Comments :: 0 Trackbacks

在JSON.org上看到j(luò)ava實(shí)現(xiàn)的源碼，想著自己寫一個(gè)Result支持JSON的返回，但是一看webwork的新版本2.2.7版本已經(jīng)支持JSON了
，但是有bug，第一,jsonObjectProperty的setter方法寫成了setJSONObjectProperty所以，在配置中若使用了jsonObjectProperty做為參數(shù)名，那么是不能set參數(shù)進(jìn)去的。另外，它不支持自定義返回js的編碼，造成亂碼，或者干脆都無法正常調(diào)用js，還有就是我覺得可以再封裝得好一點(diǎn)，對(duì)于JSONObject的生成，可以利用反射來做，而不是在每個(gè)Action中都手工的寫生成JSONObject的代碼，所以我做了一下改進(jìn)：

package com.csair.hunan.common.web;
2

import java.io.OutputStream;
4

import java.lang.reflect.Field;
5

import javax.servlet.http.HttpServletResponse;
7

import org.apache.commons.logging.Log;
9

import org.apache.commons.logging.LogFactory;
10

import org.json.JSONObject;
11

import com.opensymphony.webwork.ServletActionContext;
13

import com.opensymphony.webwork.WebWorkException;
14

import com.opensymphony.xwork.ActionContext;
15

import com.opensymphony.xwork.ActionInvocation;
16

import com.opensymphony.xwork.Result;
17

public class JSONResult implements Result {
19

private static final Log LOG = LogFactory.getLog(JSONResult.class);
21

private String jsonObjectProperty = "jsonObject";
23

private String contentType = "application/json";
24

private String encoding = "utf-8";
25

public void setEncoding(String encoding) {
27

this.encoding = encoding;
28

}
29

/**
30

* Returns the property which will be used to lookup {@link JSONObject} in WebWork's ValueStack. Default to
31

* 'jsonObject'.
32

*
33

* @return String
34

*/
35

public String getJsonObjectProperty() {
37

return jsonObjectProperty;
38

}
39

/**
40

* Set the property which will be used to lookup {@link JSONObject} in WebWork's ValueStack. Default to
41

* 'jsonObject'.
42

*
43

* @param jsonObject
44

*/
45

public void setJsonObjectProperty(String jsonObjectProperty) {
47

this.jsonObjectProperty = jsonObjectProperty;
48

}
49

/**
51

* Returns the content-type header to be used. Default to 'application/json'.
52

*
53

* @return String
54

*/
55

public String getContentType() {
56

return contentType;
57

}
58

/**
60

* Set the content-type header to be used. Default to 'application/json'.
61

*
62

* @param contentType
63

*/
64

public void setContentType(String contentType) {
65

this.contentType = contentType;
66

}
67

/**
70

* Writes the string representation of {@link JSONObject} defined through {@link #getJSONObjectProperty()}
71

* to {@link javax.servlet.http.HttpServletResponse}'s outputstream.
72

*
73

* @param invocation
74

* @throws Exception
75

*/
76

public void execute(ActionInvocation invocation) throws Exception {
77

if (LOG.isDebugEnabled()) {
79

LOG.debug("executing JSONResult");
80

}
81

JSONObject jsonObject = getJSONObject(invocation);
83

if (jsonObject != null) {
84

String json = jsonObject.toString();
85

HttpServletResponse response = getServletResponse(invocation);
86

response.setContentType(getContentType());
87

//encoding
88

byte[] bs = json.getBytes(this.encoding);
89

response.setContentLength(bs.length);
90

OutputStream os = response.getOutputStream();
92

os.write(bs);
93

os.flush();
94

if (LOG.isDebugEnabled()) {
96

LOG.debug("written ["+json+"] to HttpServletResponse outputstream");
97

}
98

}
99

}
100

101

/**
102

* Attempt to look up a {@link com.opensymphony.webwork.dispatcher.json.JSONObject} instance through the property
103

* ({@link #getJSONObjectProperty()}) by looking up the property in WebWork's ValueStack. It shall be found if there's
104

* accessor method for the property in WebWork's action itself.
105

* <p/>
106

* Returns null if one cannot be found.
107

* <p/>
108

* We could override this method to return the desired JSONObject when writing testcases.
109

*
110

* @param invocation
111

* @return {@link JSONObject} or null if one cannot be found
112

*/
113

protected JSONObject getJSONObject(ActionInvocation invocation) throws Exception {
114

ActionContext actionContext = invocation.getInvocationContext();
115

Object obj = actionContext.getValueStack().findValue(jsonObjectProperty);
116

117

118

if (obj == null) {
119

LOG.error("property ["+ jsonObjectProperty +"] returns null, expecting JSONObject", new WebWorkException());
120

return null;
121

}
122

//if the assigned object is not an instance of JSONObject, try to build one use reflection
123

if (! JSONObject.class.isInstance(obj)) {
124

LOG.warn("property ["+ jsonObjectProperty +"] is ["+obj+"] especting an instance of JSONObject", new WebWorkException());
125

LOG.debug("build json object by reflection.");
126

JSONObject jsonObj = new JSONObject();
127

for (Field field : obj.getClass().getDeclaredFields()) {
128

String getter = "get" + Character.toUpperCase(field.getName().charAt(0)) + field.getName().substring(1);
129

jsonObj.append(field.getName(), obj.getClass().getDeclaredMethod(getter).invoke(obj));
130

}
131

return jsonObj;
132

}
133

134

return (JSONObject) obj;
135

}
136

137

138

/**
139

* Returns a {@link javax.servlet.http.HttpServletResponse} by looking it up through WebWork's ActionContext Map.
140

* </p>
141

* We could override this method to return the desired Mock HttpServletResponse when writing testcases.
142

*
143

* @param invocation
144

* @return {@link javax.servlet.http.HttpServletResponse}
145

*/
146

protected HttpServletResponse getServletResponse(ActionInvocation invocation) {
147

return (HttpServletResponse) invocation.getInvocationContext().getContextMap().get(ServletActionContext.HTTP_RESPONSE);
148

}
149

}
150

posted on 2008-05-23 16:47 vulcan 閱讀(2244) 評(píng)論(0) 編輯收藏

新用戶注冊(cè) 刷新評(píng)論列表


只有注冊(cè)用戶登錄后才能發(fā)表評(píng)論。




網(wǎng)站導(dǎo)航: 博客園 IT新聞 Chat2DB C++博客博問管理

vulcan

隨筆分類

隨筆檔案

文章分類

文章檔案

博客

搜索

最新評(píng)論

閱讀排行榜